mirror of
https://github.com/c64scene-ar/llvm-6502.git
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da4471d726
Patch by Richard (legalize at xmission dot com). Differential Revision: http://reviews.llvm.org/D8154 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231617 91177308-0d34-0410-b5e6-96231b3b80d8
4643 lines
171 KiB
C++
4643 lines
171 KiB
C++
//===- CodeGenPrepare.cpp - Prepare a function for code generation --------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass munges the code in the input function to better prepare it for
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// SelectionDAG-based code generation. This works around limitations in it's
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// basic-block-at-a-time approach. It should eventually be removed.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/Passes.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/Analysis/TargetLibraryInfo.h"
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#include "llvm/Analysis/TargetTransformInfo.h"
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#include "llvm/IR/CallSite.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/DataLayout.h"
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#include "llvm/IR/DerivedTypes.h"
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#include "llvm/IR/Dominators.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/GetElementPtrTypeIterator.h"
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#include "llvm/IR/IRBuilder.h"
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#include "llvm/IR/InlineAsm.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/IntrinsicInst.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/IR/Statepoint.h"
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#include "llvm/IR/ValueHandle.h"
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#include "llvm/IR/ValueMap.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetLowering.h"
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#include "llvm/Target/TargetSubtargetInfo.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/BuildLibCalls.h"
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#include "llvm/Transforms/Utils/BypassSlowDivision.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
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using namespace llvm;
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using namespace llvm::PatternMatch;
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#define DEBUG_TYPE "codegenprepare"
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STATISTIC(NumBlocksElim, "Number of blocks eliminated");
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STATISTIC(NumPHIsElim, "Number of trivial PHIs eliminated");
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STATISTIC(NumGEPsElim, "Number of GEPs converted to casts");
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STATISTIC(NumCmpUses, "Number of uses of Cmp expressions replaced with uses of "
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"sunken Cmps");
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STATISTIC(NumCastUses, "Number of uses of Cast expressions replaced with uses "
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"of sunken Casts");
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STATISTIC(NumMemoryInsts, "Number of memory instructions whose address "
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"computations were sunk");
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STATISTIC(NumExtsMoved, "Number of [s|z]ext instructions combined with loads");
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STATISTIC(NumExtUses, "Number of uses of [s|z]ext instructions optimized");
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STATISTIC(NumRetsDup, "Number of return instructions duplicated");
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STATISTIC(NumDbgValueMoved, "Number of debug value instructions moved");
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STATISTIC(NumSelectsExpanded, "Number of selects turned into branches");
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STATISTIC(NumAndCmpsMoved, "Number of and/cmp's pushed into branches");
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STATISTIC(NumStoreExtractExposed, "Number of store(extractelement) exposed");
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static cl::opt<bool> DisableBranchOpts(
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"disable-cgp-branch-opts", cl::Hidden, cl::init(false),
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cl::desc("Disable branch optimizations in CodeGenPrepare"));
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static cl::opt<bool>
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DisableGCOpts("disable-cgp-gc-opts", cl::Hidden, cl::init(false),
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cl::desc("Disable GC optimizations in CodeGenPrepare"));
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static cl::opt<bool> DisableSelectToBranch(
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"disable-cgp-select2branch", cl::Hidden, cl::init(false),
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cl::desc("Disable select to branch conversion."));
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static cl::opt<bool> AddrSinkUsingGEPs(
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"addr-sink-using-gep", cl::Hidden, cl::init(false),
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cl::desc("Address sinking in CGP using GEPs."));
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static cl::opt<bool> EnableAndCmpSinking(
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"enable-andcmp-sinking", cl::Hidden, cl::init(true),
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cl::desc("Enable sinkinig and/cmp into branches."));
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static cl::opt<bool> DisableStoreExtract(
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"disable-cgp-store-extract", cl::Hidden, cl::init(false),
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cl::desc("Disable store(extract) optimizations in CodeGenPrepare"));
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static cl::opt<bool> StressStoreExtract(
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"stress-cgp-store-extract", cl::Hidden, cl::init(false),
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cl::desc("Stress test store(extract) optimizations in CodeGenPrepare"));
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static cl::opt<bool> DisableExtLdPromotion(
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"disable-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
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cl::desc("Disable ext(promotable(ld)) -> promoted(ext(ld)) optimization in "
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"CodeGenPrepare"));
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static cl::opt<bool> StressExtLdPromotion(
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"stress-cgp-ext-ld-promotion", cl::Hidden, cl::init(false),
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cl::desc("Stress test ext(promotable(ld)) -> promoted(ext(ld)) "
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"optimization in CodeGenPrepare"));
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namespace {
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typedef SmallPtrSet<Instruction *, 16> SetOfInstrs;
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struct TypeIsSExt {
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Type *Ty;
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bool IsSExt;
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TypeIsSExt(Type *Ty, bool IsSExt) : Ty(Ty), IsSExt(IsSExt) {}
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};
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typedef DenseMap<Instruction *, TypeIsSExt> InstrToOrigTy;
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class TypePromotionTransaction;
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class CodeGenPrepare : public FunctionPass {
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/// TLI - Keep a pointer of a TargetLowering to consult for determining
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/// transformation profitability.
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const TargetMachine *TM;
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const TargetLowering *TLI;
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const TargetTransformInfo *TTI;
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const TargetLibraryInfo *TLInfo;
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DominatorTree *DT;
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/// CurInstIterator - As we scan instructions optimizing them, this is the
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/// next instruction to optimize. Xforms that can invalidate this should
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/// update it.
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BasicBlock::iterator CurInstIterator;
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/// Keeps track of non-local addresses that have been sunk into a block.
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/// This allows us to avoid inserting duplicate code for blocks with
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/// multiple load/stores of the same address.
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ValueMap<Value*, Value*> SunkAddrs;
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/// Keeps track of all truncates inserted for the current function.
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SetOfInstrs InsertedTruncsSet;
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/// Keeps track of the type of the related instruction before their
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/// promotion for the current function.
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InstrToOrigTy PromotedInsts;
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/// ModifiedDT - If CFG is modified in anyway, dominator tree may need to
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/// be updated.
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bool ModifiedDT;
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/// OptSize - True if optimizing for size.
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bool OptSize;
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public:
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static char ID; // Pass identification, replacement for typeid
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explicit CodeGenPrepare(const TargetMachine *TM = nullptr)
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: FunctionPass(ID), TM(TM), TLI(nullptr), TTI(nullptr) {
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initializeCodeGenPreparePass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F) override;
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const char *getPassName() const override { return "CodeGen Prepare"; }
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addPreserved<DominatorTreeWrapperPass>();
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AU.addRequired<TargetLibraryInfoWrapperPass>();
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AU.addRequired<TargetTransformInfoWrapperPass>();
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}
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private:
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bool EliminateFallThrough(Function &F);
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bool EliminateMostlyEmptyBlocks(Function &F);
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bool CanMergeBlocks(const BasicBlock *BB, const BasicBlock *DestBB) const;
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void EliminateMostlyEmptyBlock(BasicBlock *BB);
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bool OptimizeBlock(BasicBlock &BB, bool& ModifiedDT);
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bool OptimizeInst(Instruction *I, bool& ModifiedDT);
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bool OptimizeMemoryInst(Instruction *I, Value *Addr, Type *AccessTy);
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bool OptimizeInlineAsmInst(CallInst *CS);
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bool OptimizeCallInst(CallInst *CI, bool& ModifiedDT);
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bool MoveExtToFormExtLoad(Instruction *&I);
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bool OptimizeExtUses(Instruction *I);
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bool OptimizeSelectInst(SelectInst *SI);
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bool OptimizeShuffleVectorInst(ShuffleVectorInst *SI);
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bool OptimizeExtractElementInst(Instruction *Inst);
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bool DupRetToEnableTailCallOpts(BasicBlock *BB);
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bool PlaceDbgValues(Function &F);
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bool sinkAndCmp(Function &F);
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bool ExtLdPromotion(TypePromotionTransaction &TPT, LoadInst *&LI,
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Instruction *&Inst,
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const SmallVectorImpl<Instruction *> &Exts,
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unsigned CreatedInst);
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bool splitBranchCondition(Function &F);
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bool simplifyOffsetableRelocate(Instruction &I);
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};
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}
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char CodeGenPrepare::ID = 0;
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INITIALIZE_TM_PASS(CodeGenPrepare, "codegenprepare",
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"Optimize for code generation", false, false)
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FunctionPass *llvm::createCodeGenPreparePass(const TargetMachine *TM) {
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return new CodeGenPrepare(TM);
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}
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bool CodeGenPrepare::runOnFunction(Function &F) {
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if (skipOptnoneFunction(F))
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return false;
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bool EverMadeChange = false;
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// Clear per function information.
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InsertedTruncsSet.clear();
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PromotedInsts.clear();
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ModifiedDT = false;
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if (TM)
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TLI = TM->getSubtargetImpl(F)->getTargetLowering();
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TLInfo = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
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TTI = &getAnalysis<TargetTransformInfoWrapperPass>().getTTI(F);
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DominatorTreeWrapperPass *DTWP =
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getAnalysisIfAvailable<DominatorTreeWrapperPass>();
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DT = DTWP ? &DTWP->getDomTree() : nullptr;
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OptSize = F.hasFnAttribute(Attribute::OptimizeForSize);
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/// This optimization identifies DIV instructions that can be
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/// profitably bypassed and carried out with a shorter, faster divide.
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if (!OptSize && TLI && TLI->isSlowDivBypassed()) {
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const DenseMap<unsigned int, unsigned int> &BypassWidths =
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TLI->getBypassSlowDivWidths();
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for (Function::iterator I = F.begin(); I != F.end(); I++)
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EverMadeChange |= bypassSlowDivision(F, I, BypassWidths);
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}
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// Eliminate blocks that contain only PHI nodes and an
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// unconditional branch.
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EverMadeChange |= EliminateMostlyEmptyBlocks(F);
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// llvm.dbg.value is far away from the value then iSel may not be able
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// handle it properly. iSel will drop llvm.dbg.value if it can not
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// find a node corresponding to the value.
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EverMadeChange |= PlaceDbgValues(F);
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// If there is a mask, compare against zero, and branch that can be combined
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// into a single target instruction, push the mask and compare into branch
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// users. Do this before OptimizeBlock -> OptimizeInst ->
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// OptimizeCmpExpression, which perturbs the pattern being searched for.
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if (!DisableBranchOpts) {
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EverMadeChange |= sinkAndCmp(F);
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EverMadeChange |= splitBranchCondition(F);
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}
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bool MadeChange = true;
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while (MadeChange) {
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MadeChange = false;
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for (Function::iterator I = F.begin(); I != F.end(); ) {
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BasicBlock *BB = I++;
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bool ModifiedDTOnIteration = false;
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MadeChange |= OptimizeBlock(*BB, ModifiedDTOnIteration);
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// Restart BB iteration if the dominator tree of the Function was changed
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ModifiedDT |= ModifiedDTOnIteration;
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if (ModifiedDTOnIteration)
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break;
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}
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EverMadeChange |= MadeChange;
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}
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SunkAddrs.clear();
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if (!DisableBranchOpts) {
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MadeChange = false;
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SmallPtrSet<BasicBlock*, 8> WorkList;
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for (BasicBlock &BB : F) {
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SmallVector<BasicBlock *, 2> Successors(succ_begin(&BB), succ_end(&BB));
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MadeChange |= ConstantFoldTerminator(&BB, true);
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if (!MadeChange) continue;
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for (SmallVectorImpl<BasicBlock*>::iterator
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II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
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if (pred_begin(*II) == pred_end(*II))
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WorkList.insert(*II);
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}
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// Delete the dead blocks and any of their dead successors.
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MadeChange |= !WorkList.empty();
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while (!WorkList.empty()) {
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BasicBlock *BB = *WorkList.begin();
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WorkList.erase(BB);
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SmallVector<BasicBlock*, 2> Successors(succ_begin(BB), succ_end(BB));
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DeleteDeadBlock(BB);
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for (SmallVectorImpl<BasicBlock*>::iterator
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II = Successors.begin(), IE = Successors.end(); II != IE; ++II)
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if (pred_begin(*II) == pred_end(*II))
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WorkList.insert(*II);
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}
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// Merge pairs of basic blocks with unconditional branches, connected by
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// a single edge.
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if (EverMadeChange || MadeChange)
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MadeChange |= EliminateFallThrough(F);
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if (MadeChange)
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ModifiedDT = true;
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EverMadeChange |= MadeChange;
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}
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if (!DisableGCOpts) {
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SmallVector<Instruction *, 2> Statepoints;
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for (BasicBlock &BB : F)
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for (Instruction &I : BB)
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if (isStatepoint(I))
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Statepoints.push_back(&I);
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for (auto &I : Statepoints)
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EverMadeChange |= simplifyOffsetableRelocate(*I);
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}
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if (ModifiedDT && DT)
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DT->recalculate(F);
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return EverMadeChange;
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}
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/// EliminateFallThrough - Merge basic blocks which are connected
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/// by a single edge, where one of the basic blocks has a single successor
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/// pointing to the other basic block, which has a single predecessor.
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bool CodeGenPrepare::EliminateFallThrough(Function &F) {
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bool Changed = false;
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// Scan all of the blocks in the function, except for the entry block.
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for (Function::iterator I = std::next(F.begin()), E = F.end(); I != E;) {
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BasicBlock *BB = I++;
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// If the destination block has a single pred, then this is a trivial
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// edge, just collapse it.
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BasicBlock *SinglePred = BB->getSinglePredecessor();
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// Don't merge if BB's address is taken.
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if (!SinglePred || SinglePred == BB || BB->hasAddressTaken()) continue;
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BranchInst *Term = dyn_cast<BranchInst>(SinglePred->getTerminator());
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if (Term && !Term->isConditional()) {
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Changed = true;
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DEBUG(dbgs() << "To merge:\n"<< *SinglePred << "\n\n\n");
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// Remember if SinglePred was the entry block of the function.
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// If so, we will need to move BB back to the entry position.
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bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
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MergeBasicBlockIntoOnlyPred(BB, DT);
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if (isEntry && BB != &BB->getParent()->getEntryBlock())
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BB->moveBefore(&BB->getParent()->getEntryBlock());
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// We have erased a block. Update the iterator.
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I = BB;
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}
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}
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return Changed;
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}
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/// EliminateMostlyEmptyBlocks - eliminate blocks that contain only PHI nodes,
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/// debug info directives, and an unconditional branch. Passes before isel
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/// (e.g. LSR/loopsimplify) often split edges in ways that are non-optimal for
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/// isel. Start by eliminating these blocks so we can split them the way we
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/// want them.
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bool CodeGenPrepare::EliminateMostlyEmptyBlocks(Function &F) {
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bool MadeChange = false;
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// Note that this intentionally skips the entry block.
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for (Function::iterator I = std::next(F.begin()), E = F.end(); I != E;) {
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BasicBlock *BB = I++;
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// If this block doesn't end with an uncond branch, ignore it.
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BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator());
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if (!BI || !BI->isUnconditional())
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continue;
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// If the instruction before the branch (skipping debug info) isn't a phi
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// node, then other stuff is happening here.
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BasicBlock::iterator BBI = BI;
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if (BBI != BB->begin()) {
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--BBI;
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while (isa<DbgInfoIntrinsic>(BBI)) {
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if (BBI == BB->begin())
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break;
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--BBI;
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}
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if (!isa<DbgInfoIntrinsic>(BBI) && !isa<PHINode>(BBI))
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continue;
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}
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// Do not break infinite loops.
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BasicBlock *DestBB = BI->getSuccessor(0);
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if (DestBB == BB)
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continue;
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if (!CanMergeBlocks(BB, DestBB))
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continue;
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EliminateMostlyEmptyBlock(BB);
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MadeChange = true;
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}
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return MadeChange;
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}
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/// CanMergeBlocks - Return true if we can merge BB into DestBB if there is a
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/// single uncond branch between them, and BB contains no other non-phi
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/// instructions.
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bool CodeGenPrepare::CanMergeBlocks(const BasicBlock *BB,
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const BasicBlock *DestBB) const {
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// We only want to eliminate blocks whose phi nodes are used by phi nodes in
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// the successor. If there are more complex condition (e.g. preheaders),
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// don't mess around with them.
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BasicBlock::const_iterator BBI = BB->begin();
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while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
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for (const User *U : PN->users()) {
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const Instruction *UI = cast<Instruction>(U);
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if (UI->getParent() != DestBB || !isa<PHINode>(UI))
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return false;
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// If User is inside DestBB block and it is a PHINode then check
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// incoming value. If incoming value is not from BB then this is
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// a complex condition (e.g. preheaders) we want to avoid here.
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if (UI->getParent() == DestBB) {
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if (const PHINode *UPN = dyn_cast<PHINode>(UI))
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for (unsigned I = 0, E = UPN->getNumIncomingValues(); I != E; ++I) {
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Instruction *Insn = dyn_cast<Instruction>(UPN->getIncomingValue(I));
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if (Insn && Insn->getParent() == BB &&
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Insn->getParent() != UPN->getIncomingBlock(I))
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return false;
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}
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}
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}
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}
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// If BB and DestBB contain any common predecessors, then the phi nodes in BB
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// and DestBB may have conflicting incoming values for the block. If so, we
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// can't merge the block.
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const PHINode *DestBBPN = dyn_cast<PHINode>(DestBB->begin());
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if (!DestBBPN) return true; // no conflict.
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// Collect the preds of BB.
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SmallPtrSet<const BasicBlock*, 16> BBPreds;
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if (const PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
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// It is faster to get preds from a PHI than with pred_iterator.
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for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
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BBPreds.insert(BBPN->getIncomingBlock(i));
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} else {
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BBPreds.insert(pred_begin(BB), pred_end(BB));
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}
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// Walk the preds of DestBB.
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for (unsigned i = 0, e = DestBBPN->getNumIncomingValues(); i != e; ++i) {
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BasicBlock *Pred = DestBBPN->getIncomingBlock(i);
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if (BBPreds.count(Pred)) { // Common predecessor?
|
|
BBI = DestBB->begin();
|
|
while (const PHINode *PN = dyn_cast<PHINode>(BBI++)) {
|
|
const Value *V1 = PN->getIncomingValueForBlock(Pred);
|
|
const Value *V2 = PN->getIncomingValueForBlock(BB);
|
|
|
|
// If V2 is a phi node in BB, look up what the mapped value will be.
|
|
if (const PHINode *V2PN = dyn_cast<PHINode>(V2))
|
|
if (V2PN->getParent() == BB)
|
|
V2 = V2PN->getIncomingValueForBlock(Pred);
|
|
|
|
// If there is a conflict, bail out.
|
|
if (V1 != V2) return false;
|
|
}
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
/// EliminateMostlyEmptyBlock - Eliminate a basic block that have only phi's and
|
|
/// an unconditional branch in it.
|
|
void CodeGenPrepare::EliminateMostlyEmptyBlock(BasicBlock *BB) {
|
|
BranchInst *BI = cast<BranchInst>(BB->getTerminator());
|
|
BasicBlock *DestBB = BI->getSuccessor(0);
|
|
|
|
DEBUG(dbgs() << "MERGING MOSTLY EMPTY BLOCKS - BEFORE:\n" << *BB << *DestBB);
|
|
|
|
// If the destination block has a single pred, then this is a trivial edge,
|
|
// just collapse it.
|
|
if (BasicBlock *SinglePred = DestBB->getSinglePredecessor()) {
|
|
if (SinglePred != DestBB) {
|
|
// Remember if SinglePred was the entry block of the function. If so, we
|
|
// will need to move BB back to the entry position.
|
|
bool isEntry = SinglePred == &SinglePred->getParent()->getEntryBlock();
|
|
MergeBasicBlockIntoOnlyPred(DestBB, DT);
|
|
|
|
if (isEntry && BB != &BB->getParent()->getEntryBlock())
|
|
BB->moveBefore(&BB->getParent()->getEntryBlock());
|
|
|
|
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
|
|
return;
|
|
}
|
|
}
|
|
|
|
// Otherwise, we have multiple predecessors of BB. Update the PHIs in DestBB
|
|
// to handle the new incoming edges it is about to have.
|
|
PHINode *PN;
|
|
for (BasicBlock::iterator BBI = DestBB->begin();
|
|
(PN = dyn_cast<PHINode>(BBI)); ++BBI) {
|
|
// Remove the incoming value for BB, and remember it.
|
|
Value *InVal = PN->removeIncomingValue(BB, false);
|
|
|
|
// Two options: either the InVal is a phi node defined in BB or it is some
|
|
// value that dominates BB.
|
|
PHINode *InValPhi = dyn_cast<PHINode>(InVal);
|
|
if (InValPhi && InValPhi->getParent() == BB) {
|
|
// Add all of the input values of the input PHI as inputs of this phi.
|
|
for (unsigned i = 0, e = InValPhi->getNumIncomingValues(); i != e; ++i)
|
|
PN->addIncoming(InValPhi->getIncomingValue(i),
|
|
InValPhi->getIncomingBlock(i));
|
|
} else {
|
|
// Otherwise, add one instance of the dominating value for each edge that
|
|
// we will be adding.
|
|
if (PHINode *BBPN = dyn_cast<PHINode>(BB->begin())) {
|
|
for (unsigned i = 0, e = BBPN->getNumIncomingValues(); i != e; ++i)
|
|
PN->addIncoming(InVal, BBPN->getIncomingBlock(i));
|
|
} else {
|
|
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
|
|
PN->addIncoming(InVal, *PI);
|
|
}
|
|
}
|
|
}
|
|
|
|
// The PHIs are now updated, change everything that refers to BB to use
|
|
// DestBB and remove BB.
|
|
BB->replaceAllUsesWith(DestBB);
|
|
if (DT && !ModifiedDT) {
|
|
BasicBlock *BBIDom = DT->getNode(BB)->getIDom()->getBlock();
|
|
BasicBlock *DestBBIDom = DT->getNode(DestBB)->getIDom()->getBlock();
|
|
BasicBlock *NewIDom = DT->findNearestCommonDominator(BBIDom, DestBBIDom);
|
|
DT->changeImmediateDominator(DestBB, NewIDom);
|
|
DT->eraseNode(BB);
|
|
}
|
|
BB->eraseFromParent();
|
|
++NumBlocksElim;
|
|
|
|
DEBUG(dbgs() << "AFTER:\n" << *DestBB << "\n\n\n");
|
|
}
|
|
|
|
// Computes a map of base pointer relocation instructions to corresponding
|
|
// derived pointer relocation instructions given a vector of all relocate calls
|
|
static void computeBaseDerivedRelocateMap(
|
|
const SmallVectorImpl<User *> &AllRelocateCalls,
|
|
DenseMap<IntrinsicInst *, SmallVector<IntrinsicInst *, 2>> &
|
|
RelocateInstMap) {
|
|
// Collect information in two maps: one primarily for locating the base object
|
|
// while filling the second map; the second map is the final structure holding
|
|
// a mapping between Base and corresponding Derived relocate calls
|
|
DenseMap<std::pair<unsigned, unsigned>, IntrinsicInst *> RelocateIdxMap;
|
|
for (auto &U : AllRelocateCalls) {
|
|
GCRelocateOperands ThisRelocate(U);
|
|
IntrinsicInst *I = cast<IntrinsicInst>(U);
|
|
auto K = std::make_pair(ThisRelocate.basePtrIndex(),
|
|
ThisRelocate.derivedPtrIndex());
|
|
RelocateIdxMap.insert(std::make_pair(K, I));
|
|
}
|
|
for (auto &Item : RelocateIdxMap) {
|
|
std::pair<unsigned, unsigned> Key = Item.first;
|
|
if (Key.first == Key.second)
|
|
// Base relocation: nothing to insert
|
|
continue;
|
|
|
|
IntrinsicInst *I = Item.second;
|
|
auto BaseKey = std::make_pair(Key.first, Key.first);
|
|
|
|
// We're iterating over RelocateIdxMap so we cannot modify it.
|
|
auto MaybeBase = RelocateIdxMap.find(BaseKey);
|
|
if (MaybeBase == RelocateIdxMap.end())
|
|
// TODO: We might want to insert a new base object relocate and gep off
|
|
// that, if there are enough derived object relocates.
|
|
continue;
|
|
|
|
RelocateInstMap[MaybeBase->second].push_back(I);
|
|
}
|
|
}
|
|
|
|
// Accepts a GEP and extracts the operands into a vector provided they're all
|
|
// small integer constants
|
|
static bool getGEPSmallConstantIntOffsetV(GetElementPtrInst *GEP,
|
|
SmallVectorImpl<Value *> &OffsetV) {
|
|
for (unsigned i = 1; i < GEP->getNumOperands(); i++) {
|
|
// Only accept small constant integer operands
|
|
auto Op = dyn_cast<ConstantInt>(GEP->getOperand(i));
|
|
if (!Op || Op->getZExtValue() > 20)
|
|
return false;
|
|
}
|
|
|
|
for (unsigned i = 1; i < GEP->getNumOperands(); i++)
|
|
OffsetV.push_back(GEP->getOperand(i));
|
|
return true;
|
|
}
|
|
|
|
// Takes a RelocatedBase (base pointer relocation instruction) and Targets to
|
|
// replace, computes a replacement, and affects it.
|
|
static bool
|
|
simplifyRelocatesOffABase(IntrinsicInst *RelocatedBase,
|
|
const SmallVectorImpl<IntrinsicInst *> &Targets) {
|
|
bool MadeChange = false;
|
|
for (auto &ToReplace : Targets) {
|
|
GCRelocateOperands MasterRelocate(RelocatedBase);
|
|
GCRelocateOperands ThisRelocate(ToReplace);
|
|
|
|
assert(ThisRelocate.basePtrIndex() == MasterRelocate.basePtrIndex() &&
|
|
"Not relocating a derived object of the original base object");
|
|
if (ThisRelocate.basePtrIndex() == ThisRelocate.derivedPtrIndex()) {
|
|
// A duplicate relocate call. TODO: coalesce duplicates.
|
|
continue;
|
|
}
|
|
|
|
Value *Base = ThisRelocate.basePtr();
|
|
auto Derived = dyn_cast<GetElementPtrInst>(ThisRelocate.derivedPtr());
|
|
if (!Derived || Derived->getPointerOperand() != Base)
|
|
continue;
|
|
|
|
SmallVector<Value *, 2> OffsetV;
|
|
if (!getGEPSmallConstantIntOffsetV(Derived, OffsetV))
|
|
continue;
|
|
|
|
// Create a Builder and replace the target callsite with a gep
|
|
IRBuilder<> Builder(ToReplace);
|
|
Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
|
|
Value *Replacement =
|
|
Builder.CreateGEP(RelocatedBase, makeArrayRef(OffsetV));
|
|
Instruction *ReplacementInst = cast<Instruction>(Replacement);
|
|
ReplacementInst->removeFromParent();
|
|
ReplacementInst->insertAfter(RelocatedBase);
|
|
Replacement->takeName(ToReplace);
|
|
ToReplace->replaceAllUsesWith(Replacement);
|
|
ToReplace->eraseFromParent();
|
|
|
|
MadeChange = true;
|
|
}
|
|
return MadeChange;
|
|
}
|
|
|
|
// Turns this:
|
|
//
|
|
// %base = ...
|
|
// %ptr = gep %base + 15
|
|
// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
|
|
// %base' = relocate(%tok, i32 4, i32 4)
|
|
// %ptr' = relocate(%tok, i32 4, i32 5)
|
|
// %val = load %ptr'
|
|
//
|
|
// into this:
|
|
//
|
|
// %base = ...
|
|
// %ptr = gep %base + 15
|
|
// %tok = statepoint (%fun, i32 0, i32 0, i32 0, %base, %ptr)
|
|
// %base' = gc.relocate(%tok, i32 4, i32 4)
|
|
// %ptr' = gep %base' + 15
|
|
// %val = load %ptr'
|
|
bool CodeGenPrepare::simplifyOffsetableRelocate(Instruction &I) {
|
|
bool MadeChange = false;
|
|
SmallVector<User *, 2> AllRelocateCalls;
|
|
|
|
for (auto *U : I.users())
|
|
if (isGCRelocate(dyn_cast<Instruction>(U)))
|
|
// Collect all the relocate calls associated with a statepoint
|
|
AllRelocateCalls.push_back(U);
|
|
|
|
// We need atleast one base pointer relocation + one derived pointer
|
|
// relocation to mangle
|
|
if (AllRelocateCalls.size() < 2)
|
|
return false;
|
|
|
|
// RelocateInstMap is a mapping from the base relocate instruction to the
|
|
// corresponding derived relocate instructions
|
|
DenseMap<IntrinsicInst *, SmallVector<IntrinsicInst *, 2>> RelocateInstMap;
|
|
computeBaseDerivedRelocateMap(AllRelocateCalls, RelocateInstMap);
|
|
if (RelocateInstMap.empty())
|
|
return false;
|
|
|
|
for (auto &Item : RelocateInstMap)
|
|
// Item.first is the RelocatedBase to offset against
|
|
// Item.second is the vector of Targets to replace
|
|
MadeChange = simplifyRelocatesOffABase(Item.first, Item.second);
|
|
return MadeChange;
|
|
}
|
|
|
|
/// SinkCast - Sink the specified cast instruction into its user blocks
|
|
static bool SinkCast(CastInst *CI) {
|
|
BasicBlock *DefBB = CI->getParent();
|
|
|
|
/// InsertedCasts - Only insert a cast in each block once.
|
|
DenseMap<BasicBlock*, CastInst*> InsertedCasts;
|
|
|
|
bool MadeChange = false;
|
|
for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
|
|
UI != E; ) {
|
|
Use &TheUse = UI.getUse();
|
|
Instruction *User = cast<Instruction>(*UI);
|
|
|
|
// Figure out which BB this cast is used in. For PHI's this is the
|
|
// appropriate predecessor block.
|
|
BasicBlock *UserBB = User->getParent();
|
|
if (PHINode *PN = dyn_cast<PHINode>(User)) {
|
|
UserBB = PN->getIncomingBlock(TheUse);
|
|
}
|
|
|
|
// Preincrement use iterator so we don't invalidate it.
|
|
++UI;
|
|
|
|
// If this user is in the same block as the cast, don't change the cast.
|
|
if (UserBB == DefBB) continue;
|
|
|
|
// If we have already inserted a cast into this block, use it.
|
|
CastInst *&InsertedCast = InsertedCasts[UserBB];
|
|
|
|
if (!InsertedCast) {
|
|
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
|
|
InsertedCast =
|
|
CastInst::Create(CI->getOpcode(), CI->getOperand(0), CI->getType(), "",
|
|
InsertPt);
|
|
MadeChange = true;
|
|
}
|
|
|
|
// Replace a use of the cast with a use of the new cast.
|
|
TheUse = InsertedCast;
|
|
++NumCastUses;
|
|
}
|
|
|
|
// If we removed all uses, nuke the cast.
|
|
if (CI->use_empty()) {
|
|
CI->eraseFromParent();
|
|
MadeChange = true;
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
/// OptimizeNoopCopyExpression - If the specified cast instruction is a noop
|
|
/// copy (e.g. it's casting from one pointer type to another, i32->i8 on PPC),
|
|
/// sink it into user blocks to reduce the number of virtual
|
|
/// registers that must be created and coalesced.
|
|
///
|
|
/// Return true if any changes are made.
|
|
///
|
|
static bool OptimizeNoopCopyExpression(CastInst *CI, const TargetLowering &TLI){
|
|
// If this is a noop copy,
|
|
EVT SrcVT = TLI.getValueType(CI->getOperand(0)->getType());
|
|
EVT DstVT = TLI.getValueType(CI->getType());
|
|
|
|
// This is an fp<->int conversion?
|
|
if (SrcVT.isInteger() != DstVT.isInteger())
|
|
return false;
|
|
|
|
// If this is an extension, it will be a zero or sign extension, which
|
|
// isn't a noop.
|
|
if (SrcVT.bitsLT(DstVT)) return false;
|
|
|
|
// If these values will be promoted, find out what they will be promoted
|
|
// to. This helps us consider truncates on PPC as noop copies when they
|
|
// are.
|
|
if (TLI.getTypeAction(CI->getContext(), SrcVT) ==
|
|
TargetLowering::TypePromoteInteger)
|
|
SrcVT = TLI.getTypeToTransformTo(CI->getContext(), SrcVT);
|
|
if (TLI.getTypeAction(CI->getContext(), DstVT) ==
|
|
TargetLowering::TypePromoteInteger)
|
|
DstVT = TLI.getTypeToTransformTo(CI->getContext(), DstVT);
|
|
|
|
// If, after promotion, these are the same types, this is a noop copy.
|
|
if (SrcVT != DstVT)
|
|
return false;
|
|
|
|
return SinkCast(CI);
|
|
}
|
|
|
|
/// OptimizeCmpExpression - sink the given CmpInst into user blocks to reduce
|
|
/// the number of virtual registers that must be created and coalesced. This is
|
|
/// a clear win except on targets with multiple condition code registers
|
|
/// (PowerPC), where it might lose; some adjustment may be wanted there.
|
|
///
|
|
/// Return true if any changes are made.
|
|
static bool OptimizeCmpExpression(CmpInst *CI) {
|
|
BasicBlock *DefBB = CI->getParent();
|
|
|
|
/// InsertedCmp - Only insert a cmp in each block once.
|
|
DenseMap<BasicBlock*, CmpInst*> InsertedCmps;
|
|
|
|
bool MadeChange = false;
|
|
for (Value::user_iterator UI = CI->user_begin(), E = CI->user_end();
|
|
UI != E; ) {
|
|
Use &TheUse = UI.getUse();
|
|
Instruction *User = cast<Instruction>(*UI);
|
|
|
|
// Preincrement use iterator so we don't invalidate it.
|
|
++UI;
|
|
|
|
// Don't bother for PHI nodes.
|
|
if (isa<PHINode>(User))
|
|
continue;
|
|
|
|
// Figure out which BB this cmp is used in.
|
|
BasicBlock *UserBB = User->getParent();
|
|
|
|
// If this user is in the same block as the cmp, don't change the cmp.
|
|
if (UserBB == DefBB) continue;
|
|
|
|
// If we have already inserted a cmp into this block, use it.
|
|
CmpInst *&InsertedCmp = InsertedCmps[UserBB];
|
|
|
|
if (!InsertedCmp) {
|
|
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
|
|
InsertedCmp =
|
|
CmpInst::Create(CI->getOpcode(),
|
|
CI->getPredicate(), CI->getOperand(0),
|
|
CI->getOperand(1), "", InsertPt);
|
|
MadeChange = true;
|
|
}
|
|
|
|
// Replace a use of the cmp with a use of the new cmp.
|
|
TheUse = InsertedCmp;
|
|
++NumCmpUses;
|
|
}
|
|
|
|
// If we removed all uses, nuke the cmp.
|
|
if (CI->use_empty())
|
|
CI->eraseFromParent();
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
/// isExtractBitsCandidateUse - Check if the candidates could
|
|
/// be combined with shift instruction, which includes:
|
|
/// 1. Truncate instruction
|
|
/// 2. And instruction and the imm is a mask of the low bits:
|
|
/// imm & (imm+1) == 0
|
|
static bool isExtractBitsCandidateUse(Instruction *User) {
|
|
if (!isa<TruncInst>(User)) {
|
|
if (User->getOpcode() != Instruction::And ||
|
|
!isa<ConstantInt>(User->getOperand(1)))
|
|
return false;
|
|
|
|
const APInt &Cimm = cast<ConstantInt>(User->getOperand(1))->getValue();
|
|
|
|
if ((Cimm & (Cimm + 1)).getBoolValue())
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/// SinkShiftAndTruncate - sink both shift and truncate instruction
|
|
/// to the use of truncate's BB.
|
|
static bool
|
|
SinkShiftAndTruncate(BinaryOperator *ShiftI, Instruction *User, ConstantInt *CI,
|
|
DenseMap<BasicBlock *, BinaryOperator *> &InsertedShifts,
|
|
const TargetLowering &TLI) {
|
|
BasicBlock *UserBB = User->getParent();
|
|
DenseMap<BasicBlock *, CastInst *> InsertedTruncs;
|
|
TruncInst *TruncI = dyn_cast<TruncInst>(User);
|
|
bool MadeChange = false;
|
|
|
|
for (Value::user_iterator TruncUI = TruncI->user_begin(),
|
|
TruncE = TruncI->user_end();
|
|
TruncUI != TruncE;) {
|
|
|
|
Use &TruncTheUse = TruncUI.getUse();
|
|
Instruction *TruncUser = cast<Instruction>(*TruncUI);
|
|
// Preincrement use iterator so we don't invalidate it.
|
|
|
|
++TruncUI;
|
|
|
|
int ISDOpcode = TLI.InstructionOpcodeToISD(TruncUser->getOpcode());
|
|
if (!ISDOpcode)
|
|
continue;
|
|
|
|
// If the use is actually a legal node, there will not be an
|
|
// implicit truncate.
|
|
// FIXME: always querying the result type is just an
|
|
// approximation; some nodes' legality is determined by the
|
|
// operand or other means. There's no good way to find out though.
|
|
if (TLI.isOperationLegalOrCustom(
|
|
ISDOpcode, TLI.getValueType(TruncUser->getType(), true)))
|
|
continue;
|
|
|
|
// Don't bother for PHI nodes.
|
|
if (isa<PHINode>(TruncUser))
|
|
continue;
|
|
|
|
BasicBlock *TruncUserBB = TruncUser->getParent();
|
|
|
|
if (UserBB == TruncUserBB)
|
|
continue;
|
|
|
|
BinaryOperator *&InsertedShift = InsertedShifts[TruncUserBB];
|
|
CastInst *&InsertedTrunc = InsertedTruncs[TruncUserBB];
|
|
|
|
if (!InsertedShift && !InsertedTrunc) {
|
|
BasicBlock::iterator InsertPt = TruncUserBB->getFirstInsertionPt();
|
|
// Sink the shift
|
|
if (ShiftI->getOpcode() == Instruction::AShr)
|
|
InsertedShift =
|
|
BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI, "", InsertPt);
|
|
else
|
|
InsertedShift =
|
|
BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI, "", InsertPt);
|
|
|
|
// Sink the trunc
|
|
BasicBlock::iterator TruncInsertPt = TruncUserBB->getFirstInsertionPt();
|
|
TruncInsertPt++;
|
|
|
|
InsertedTrunc = CastInst::Create(TruncI->getOpcode(), InsertedShift,
|
|
TruncI->getType(), "", TruncInsertPt);
|
|
|
|
MadeChange = true;
|
|
|
|
TruncTheUse = InsertedTrunc;
|
|
}
|
|
}
|
|
return MadeChange;
|
|
}
|
|
|
|
/// OptimizeExtractBits - sink the shift *right* instruction into user blocks if
|
|
/// the uses could potentially be combined with this shift instruction and
|
|
/// generate BitExtract instruction. It will only be applied if the architecture
|
|
/// supports BitExtract instruction. Here is an example:
|
|
/// BB1:
|
|
/// %x.extract.shift = lshr i64 %arg1, 32
|
|
/// BB2:
|
|
/// %x.extract.trunc = trunc i64 %x.extract.shift to i16
|
|
/// ==>
|
|
///
|
|
/// BB2:
|
|
/// %x.extract.shift.1 = lshr i64 %arg1, 32
|
|
/// %x.extract.trunc = trunc i64 %x.extract.shift.1 to i16
|
|
///
|
|
/// CodeGen will recoginze the pattern in BB2 and generate BitExtract
|
|
/// instruction.
|
|
/// Return true if any changes are made.
|
|
static bool OptimizeExtractBits(BinaryOperator *ShiftI, ConstantInt *CI,
|
|
const TargetLowering &TLI) {
|
|
BasicBlock *DefBB = ShiftI->getParent();
|
|
|
|
/// Only insert instructions in each block once.
|
|
DenseMap<BasicBlock *, BinaryOperator *> InsertedShifts;
|
|
|
|
bool shiftIsLegal = TLI.isTypeLegal(TLI.getValueType(ShiftI->getType()));
|
|
|
|
bool MadeChange = false;
|
|
for (Value::user_iterator UI = ShiftI->user_begin(), E = ShiftI->user_end();
|
|
UI != E;) {
|
|
Use &TheUse = UI.getUse();
|
|
Instruction *User = cast<Instruction>(*UI);
|
|
// Preincrement use iterator so we don't invalidate it.
|
|
++UI;
|
|
|
|
// Don't bother for PHI nodes.
|
|
if (isa<PHINode>(User))
|
|
continue;
|
|
|
|
if (!isExtractBitsCandidateUse(User))
|
|
continue;
|
|
|
|
BasicBlock *UserBB = User->getParent();
|
|
|
|
if (UserBB == DefBB) {
|
|
// If the shift and truncate instruction are in the same BB. The use of
|
|
// the truncate(TruncUse) may still introduce another truncate if not
|
|
// legal. In this case, we would like to sink both shift and truncate
|
|
// instruction to the BB of TruncUse.
|
|
// for example:
|
|
// BB1:
|
|
// i64 shift.result = lshr i64 opnd, imm
|
|
// trunc.result = trunc shift.result to i16
|
|
//
|
|
// BB2:
|
|
// ----> We will have an implicit truncate here if the architecture does
|
|
// not have i16 compare.
|
|
// cmp i16 trunc.result, opnd2
|
|
//
|
|
if (isa<TruncInst>(User) && shiftIsLegal
|
|
// If the type of the truncate is legal, no trucate will be
|
|
// introduced in other basic blocks.
|
|
&& (!TLI.isTypeLegal(TLI.getValueType(User->getType()))))
|
|
MadeChange =
|
|
SinkShiftAndTruncate(ShiftI, User, CI, InsertedShifts, TLI);
|
|
|
|
continue;
|
|
}
|
|
// If we have already inserted a shift into this block, use it.
|
|
BinaryOperator *&InsertedShift = InsertedShifts[UserBB];
|
|
|
|
if (!InsertedShift) {
|
|
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
|
|
|
|
if (ShiftI->getOpcode() == Instruction::AShr)
|
|
InsertedShift =
|
|
BinaryOperator::CreateAShr(ShiftI->getOperand(0), CI, "", InsertPt);
|
|
else
|
|
InsertedShift =
|
|
BinaryOperator::CreateLShr(ShiftI->getOperand(0), CI, "", InsertPt);
|
|
|
|
MadeChange = true;
|
|
}
|
|
|
|
// Replace a use of the shift with a use of the new shift.
|
|
TheUse = InsertedShift;
|
|
}
|
|
|
|
// If we removed all uses, nuke the shift.
|
|
if (ShiftI->use_empty())
|
|
ShiftI->eraseFromParent();
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
// ScalarizeMaskedLoad() translates masked load intrinsic, like
|
|
// <16 x i32 > @llvm.masked.load( <16 x i32>* %addr, i32 align,
|
|
// <16 x i1> %mask, <16 x i32> %passthru)
|
|
// to a chain of basic blocks, whith loading element one-by-one if
|
|
// the appropriate mask bit is set
|
|
//
|
|
// %1 = bitcast i8* %addr to i32*
|
|
// %2 = extractelement <16 x i1> %mask, i32 0
|
|
// %3 = icmp eq i1 %2, true
|
|
// br i1 %3, label %cond.load, label %else
|
|
//
|
|
//cond.load: ; preds = %0
|
|
// %4 = getelementptr i32* %1, i32 0
|
|
// %5 = load i32* %4
|
|
// %6 = insertelement <16 x i32> undef, i32 %5, i32 0
|
|
// br label %else
|
|
//
|
|
//else: ; preds = %0, %cond.load
|
|
// %res.phi.else = phi <16 x i32> [ %6, %cond.load ], [ undef, %0 ]
|
|
// %7 = extractelement <16 x i1> %mask, i32 1
|
|
// %8 = icmp eq i1 %7, true
|
|
// br i1 %8, label %cond.load1, label %else2
|
|
//
|
|
//cond.load1: ; preds = %else
|
|
// %9 = getelementptr i32* %1, i32 1
|
|
// %10 = load i32* %9
|
|
// %11 = insertelement <16 x i32> %res.phi.else, i32 %10, i32 1
|
|
// br label %else2
|
|
//
|
|
//else2: ; preds = %else, %cond.load1
|
|
// %res.phi.else3 = phi <16 x i32> [ %11, %cond.load1 ], [ %res.phi.else, %else ]
|
|
// %12 = extractelement <16 x i1> %mask, i32 2
|
|
// %13 = icmp eq i1 %12, true
|
|
// br i1 %13, label %cond.load4, label %else5
|
|
//
|
|
static void ScalarizeMaskedLoad(CallInst *CI) {
|
|
Value *Ptr = CI->getArgOperand(0);
|
|
Value *Src0 = CI->getArgOperand(3);
|
|
Value *Mask = CI->getArgOperand(2);
|
|
VectorType *VecType = dyn_cast<VectorType>(CI->getType());
|
|
Type *EltTy = VecType->getElementType();
|
|
|
|
assert(VecType && "Unexpected return type of masked load intrinsic");
|
|
|
|
IRBuilder<> Builder(CI->getContext());
|
|
Instruction *InsertPt = CI;
|
|
BasicBlock *IfBlock = CI->getParent();
|
|
BasicBlock *CondBlock = nullptr;
|
|
BasicBlock *PrevIfBlock = CI->getParent();
|
|
Builder.SetInsertPoint(InsertPt);
|
|
|
|
Builder.SetCurrentDebugLocation(CI->getDebugLoc());
|
|
|
|
// Bitcast %addr fron i8* to EltTy*
|
|
Type *NewPtrType =
|
|
EltTy->getPointerTo(cast<PointerType>(Ptr->getType())->getAddressSpace());
|
|
Value *FirstEltPtr = Builder.CreateBitCast(Ptr, NewPtrType);
|
|
Value *UndefVal = UndefValue::get(VecType);
|
|
|
|
// The result vector
|
|
Value *VResult = UndefVal;
|
|
|
|
PHINode *Phi = nullptr;
|
|
Value *PrevPhi = UndefVal;
|
|
|
|
unsigned VectorWidth = VecType->getNumElements();
|
|
for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
|
|
|
|
// Fill the "else" block, created in the previous iteration
|
|
//
|
|
// %res.phi.else3 = phi <16 x i32> [ %11, %cond.load1 ], [ %res.phi.else, %else ]
|
|
// %mask_1 = extractelement <16 x i1> %mask, i32 Idx
|
|
// %to_load = icmp eq i1 %mask_1, true
|
|
// br i1 %to_load, label %cond.load, label %else
|
|
//
|
|
if (Idx > 0) {
|
|
Phi = Builder.CreatePHI(VecType, 2, "res.phi.else");
|
|
Phi->addIncoming(VResult, CondBlock);
|
|
Phi->addIncoming(PrevPhi, PrevIfBlock);
|
|
PrevPhi = Phi;
|
|
VResult = Phi;
|
|
}
|
|
|
|
Value *Predicate = Builder.CreateExtractElement(Mask, Builder.getInt32(Idx));
|
|
Value *Cmp = Builder.CreateICmp(ICmpInst::ICMP_EQ, Predicate,
|
|
ConstantInt::get(Predicate->getType(), 1));
|
|
|
|
// Create "cond" block
|
|
//
|
|
// %EltAddr = getelementptr i32* %1, i32 0
|
|
// %Elt = load i32* %EltAddr
|
|
// VResult = insertelement <16 x i32> VResult, i32 %Elt, i32 Idx
|
|
//
|
|
CondBlock = IfBlock->splitBasicBlock(InsertPt, "cond.load");
|
|
Builder.SetInsertPoint(InsertPt);
|
|
|
|
Value* Gep = Builder.CreateInBoundsGEP(FirstEltPtr, Builder.getInt32(Idx));
|
|
LoadInst* Load = Builder.CreateLoad(Gep, false);
|
|
VResult = Builder.CreateInsertElement(VResult, Load, Builder.getInt32(Idx));
|
|
|
|
// Create "else" block, fill it in the next iteration
|
|
BasicBlock *NewIfBlock = CondBlock->splitBasicBlock(InsertPt, "else");
|
|
Builder.SetInsertPoint(InsertPt);
|
|
Instruction *OldBr = IfBlock->getTerminator();
|
|
BranchInst::Create(CondBlock, NewIfBlock, Cmp, OldBr);
|
|
OldBr->eraseFromParent();
|
|
PrevIfBlock = IfBlock;
|
|
IfBlock = NewIfBlock;
|
|
}
|
|
|
|
Phi = Builder.CreatePHI(VecType, 2, "res.phi.select");
|
|
Phi->addIncoming(VResult, CondBlock);
|
|
Phi->addIncoming(PrevPhi, PrevIfBlock);
|
|
Value *NewI = Builder.CreateSelect(Mask, Phi, Src0);
|
|
CI->replaceAllUsesWith(NewI);
|
|
CI->eraseFromParent();
|
|
}
|
|
|
|
// ScalarizeMaskedStore() translates masked store intrinsic, like
|
|
// void @llvm.masked.store(<16 x i32> %src, <16 x i32>* %addr, i32 align,
|
|
// <16 x i1> %mask)
|
|
// to a chain of basic blocks, that stores element one-by-one if
|
|
// the appropriate mask bit is set
|
|
//
|
|
// %1 = bitcast i8* %addr to i32*
|
|
// %2 = extractelement <16 x i1> %mask, i32 0
|
|
// %3 = icmp eq i1 %2, true
|
|
// br i1 %3, label %cond.store, label %else
|
|
//
|
|
// cond.store: ; preds = %0
|
|
// %4 = extractelement <16 x i32> %val, i32 0
|
|
// %5 = getelementptr i32* %1, i32 0
|
|
// store i32 %4, i32* %5
|
|
// br label %else
|
|
//
|
|
// else: ; preds = %0, %cond.store
|
|
// %6 = extractelement <16 x i1> %mask, i32 1
|
|
// %7 = icmp eq i1 %6, true
|
|
// br i1 %7, label %cond.store1, label %else2
|
|
//
|
|
// cond.store1: ; preds = %else
|
|
// %8 = extractelement <16 x i32> %val, i32 1
|
|
// %9 = getelementptr i32* %1, i32 1
|
|
// store i32 %8, i32* %9
|
|
// br label %else2
|
|
// . . .
|
|
static void ScalarizeMaskedStore(CallInst *CI) {
|
|
Value *Ptr = CI->getArgOperand(1);
|
|
Value *Src = CI->getArgOperand(0);
|
|
Value *Mask = CI->getArgOperand(3);
|
|
|
|
VectorType *VecType = dyn_cast<VectorType>(Src->getType());
|
|
Type *EltTy = VecType->getElementType();
|
|
|
|
assert(VecType && "Unexpected data type in masked store intrinsic");
|
|
|
|
IRBuilder<> Builder(CI->getContext());
|
|
Instruction *InsertPt = CI;
|
|
BasicBlock *IfBlock = CI->getParent();
|
|
Builder.SetInsertPoint(InsertPt);
|
|
Builder.SetCurrentDebugLocation(CI->getDebugLoc());
|
|
|
|
// Bitcast %addr fron i8* to EltTy*
|
|
Type *NewPtrType =
|
|
EltTy->getPointerTo(cast<PointerType>(Ptr->getType())->getAddressSpace());
|
|
Value *FirstEltPtr = Builder.CreateBitCast(Ptr, NewPtrType);
|
|
|
|
unsigned VectorWidth = VecType->getNumElements();
|
|
for (unsigned Idx = 0; Idx < VectorWidth; ++Idx) {
|
|
|
|
// Fill the "else" block, created in the previous iteration
|
|
//
|
|
// %mask_1 = extractelement <16 x i1> %mask, i32 Idx
|
|
// %to_store = icmp eq i1 %mask_1, true
|
|
// br i1 %to_load, label %cond.store, label %else
|
|
//
|
|
Value *Predicate = Builder.CreateExtractElement(Mask, Builder.getInt32(Idx));
|
|
Value *Cmp = Builder.CreateICmp(ICmpInst::ICMP_EQ, Predicate,
|
|
ConstantInt::get(Predicate->getType(), 1));
|
|
|
|
// Create "cond" block
|
|
//
|
|
// %OneElt = extractelement <16 x i32> %Src, i32 Idx
|
|
// %EltAddr = getelementptr i32* %1, i32 0
|
|
// %store i32 %OneElt, i32* %EltAddr
|
|
//
|
|
BasicBlock *CondBlock = IfBlock->splitBasicBlock(InsertPt, "cond.store");
|
|
Builder.SetInsertPoint(InsertPt);
|
|
|
|
Value *OneElt = Builder.CreateExtractElement(Src, Builder.getInt32(Idx));
|
|
Value* Gep = Builder.CreateInBoundsGEP(FirstEltPtr, Builder.getInt32(Idx));
|
|
Builder.CreateStore(OneElt, Gep);
|
|
|
|
// Create "else" block, fill it in the next iteration
|
|
BasicBlock *NewIfBlock = CondBlock->splitBasicBlock(InsertPt, "else");
|
|
Builder.SetInsertPoint(InsertPt);
|
|
Instruction *OldBr = IfBlock->getTerminator();
|
|
BranchInst::Create(CondBlock, NewIfBlock, Cmp, OldBr);
|
|
OldBr->eraseFromParent();
|
|
IfBlock = NewIfBlock;
|
|
}
|
|
CI->eraseFromParent();
|
|
}
|
|
|
|
bool CodeGenPrepare::OptimizeCallInst(CallInst *CI, bool& ModifiedDT) {
|
|
BasicBlock *BB = CI->getParent();
|
|
|
|
// Lower inline assembly if we can.
|
|
// If we found an inline asm expession, and if the target knows how to
|
|
// lower it to normal LLVM code, do so now.
|
|
if (TLI && isa<InlineAsm>(CI->getCalledValue())) {
|
|
if (TLI->ExpandInlineAsm(CI)) {
|
|
// Avoid invalidating the iterator.
|
|
CurInstIterator = BB->begin();
|
|
// Avoid processing instructions out of order, which could cause
|
|
// reuse before a value is defined.
|
|
SunkAddrs.clear();
|
|
return true;
|
|
}
|
|
// Sink address computing for memory operands into the block.
|
|
if (OptimizeInlineAsmInst(CI))
|
|
return true;
|
|
}
|
|
|
|
IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI);
|
|
if (II) {
|
|
switch (II->getIntrinsicID()) {
|
|
default: break;
|
|
case Intrinsic::objectsize: {
|
|
// Lower all uses of llvm.objectsize.*
|
|
bool Min = (cast<ConstantInt>(II->getArgOperand(1))->getZExtValue() == 1);
|
|
Type *ReturnTy = CI->getType();
|
|
Constant *RetVal = ConstantInt::get(ReturnTy, Min ? 0 : -1ULL);
|
|
|
|
// Substituting this can cause recursive simplifications, which can
|
|
// invalidate our iterator. Use a WeakVH to hold onto it in case this
|
|
// happens.
|
|
WeakVH IterHandle(CurInstIterator);
|
|
|
|
replaceAndRecursivelySimplify(CI, RetVal,
|
|
TLI ? TLI->getDataLayout() : nullptr,
|
|
TLInfo, ModifiedDT ? nullptr : DT);
|
|
|
|
// If the iterator instruction was recursively deleted, start over at the
|
|
// start of the block.
|
|
if (IterHandle != CurInstIterator) {
|
|
CurInstIterator = BB->begin();
|
|
SunkAddrs.clear();
|
|
}
|
|
return true;
|
|
}
|
|
case Intrinsic::masked_load: {
|
|
// Scalarize unsupported vector masked load
|
|
if (!TTI->isLegalMaskedLoad(CI->getType(), 1)) {
|
|
ScalarizeMaskedLoad(CI);
|
|
ModifiedDT = true;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
case Intrinsic::masked_store: {
|
|
if (!TTI->isLegalMaskedStore(CI->getArgOperand(0)->getType(), 1)) {
|
|
ScalarizeMaskedStore(CI);
|
|
ModifiedDT = true;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
}
|
|
|
|
if (TLI) {
|
|
SmallVector<Value*, 2> PtrOps;
|
|
Type *AccessTy;
|
|
if (TLI->GetAddrModeArguments(II, PtrOps, AccessTy))
|
|
while (!PtrOps.empty())
|
|
if (OptimizeMemoryInst(II, PtrOps.pop_back_val(), AccessTy))
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// From here on out we're working with named functions.
|
|
if (!CI->getCalledFunction()) return false;
|
|
|
|
// We'll need DataLayout from here on out.
|
|
const DataLayout *TD = TLI ? TLI->getDataLayout() : nullptr;
|
|
if (!TD) return false;
|
|
|
|
// Lower all default uses of _chk calls. This is very similar
|
|
// to what InstCombineCalls does, but here we are only lowering calls
|
|
// to fortified library functions (e.g. __memcpy_chk) that have the default
|
|
// "don't know" as the objectsize. Anything else should be left alone.
|
|
FortifiedLibCallSimplifier Simplifier(TD, TLInfo, true);
|
|
if (Value *V = Simplifier.optimizeCall(CI)) {
|
|
CI->replaceAllUsesWith(V);
|
|
CI->eraseFromParent();
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// DupRetToEnableTailCallOpts - Look for opportunities to duplicate return
|
|
/// instructions to the predecessor to enable tail call optimizations. The
|
|
/// case it is currently looking for is:
|
|
/// @code
|
|
/// bb0:
|
|
/// %tmp0 = tail call i32 @f0()
|
|
/// br label %return
|
|
/// bb1:
|
|
/// %tmp1 = tail call i32 @f1()
|
|
/// br label %return
|
|
/// bb2:
|
|
/// %tmp2 = tail call i32 @f2()
|
|
/// br label %return
|
|
/// return:
|
|
/// %retval = phi i32 [ %tmp0, %bb0 ], [ %tmp1, %bb1 ], [ %tmp2, %bb2 ]
|
|
/// ret i32 %retval
|
|
/// @endcode
|
|
///
|
|
/// =>
|
|
///
|
|
/// @code
|
|
/// bb0:
|
|
/// %tmp0 = tail call i32 @f0()
|
|
/// ret i32 %tmp0
|
|
/// bb1:
|
|
/// %tmp1 = tail call i32 @f1()
|
|
/// ret i32 %tmp1
|
|
/// bb2:
|
|
/// %tmp2 = tail call i32 @f2()
|
|
/// ret i32 %tmp2
|
|
/// @endcode
|
|
bool CodeGenPrepare::DupRetToEnableTailCallOpts(BasicBlock *BB) {
|
|
if (!TLI)
|
|
return false;
|
|
|
|
ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator());
|
|
if (!RI)
|
|
return false;
|
|
|
|
PHINode *PN = nullptr;
|
|
BitCastInst *BCI = nullptr;
|
|
Value *V = RI->getReturnValue();
|
|
if (V) {
|
|
BCI = dyn_cast<BitCastInst>(V);
|
|
if (BCI)
|
|
V = BCI->getOperand(0);
|
|
|
|
PN = dyn_cast<PHINode>(V);
|
|
if (!PN)
|
|
return false;
|
|
}
|
|
|
|
if (PN && PN->getParent() != BB)
|
|
return false;
|
|
|
|
// It's not safe to eliminate the sign / zero extension of the return value.
|
|
// See llvm::isInTailCallPosition().
|
|
const Function *F = BB->getParent();
|
|
AttributeSet CallerAttrs = F->getAttributes();
|
|
if (CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::ZExt) ||
|
|
CallerAttrs.hasAttribute(AttributeSet::ReturnIndex, Attribute::SExt))
|
|
return false;
|
|
|
|
// Make sure there are no instructions between the PHI and return, or that the
|
|
// return is the first instruction in the block.
|
|
if (PN) {
|
|
BasicBlock::iterator BI = BB->begin();
|
|
do { ++BI; } while (isa<DbgInfoIntrinsic>(BI));
|
|
if (&*BI == BCI)
|
|
// Also skip over the bitcast.
|
|
++BI;
|
|
if (&*BI != RI)
|
|
return false;
|
|
} else {
|
|
BasicBlock::iterator BI = BB->begin();
|
|
while (isa<DbgInfoIntrinsic>(BI)) ++BI;
|
|
if (&*BI != RI)
|
|
return false;
|
|
}
|
|
|
|
/// Only dup the ReturnInst if the CallInst is likely to be emitted as a tail
|
|
/// call.
|
|
SmallVector<CallInst*, 4> TailCalls;
|
|
if (PN) {
|
|
for (unsigned I = 0, E = PN->getNumIncomingValues(); I != E; ++I) {
|
|
CallInst *CI = dyn_cast<CallInst>(PN->getIncomingValue(I));
|
|
// Make sure the phi value is indeed produced by the tail call.
|
|
if (CI && CI->hasOneUse() && CI->getParent() == PN->getIncomingBlock(I) &&
|
|
TLI->mayBeEmittedAsTailCall(CI))
|
|
TailCalls.push_back(CI);
|
|
}
|
|
} else {
|
|
SmallPtrSet<BasicBlock*, 4> VisitedBBs;
|
|
for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE; ++PI) {
|
|
if (!VisitedBBs.insert(*PI).second)
|
|
continue;
|
|
|
|
BasicBlock::InstListType &InstList = (*PI)->getInstList();
|
|
BasicBlock::InstListType::reverse_iterator RI = InstList.rbegin();
|
|
BasicBlock::InstListType::reverse_iterator RE = InstList.rend();
|
|
do { ++RI; } while (RI != RE && isa<DbgInfoIntrinsic>(&*RI));
|
|
if (RI == RE)
|
|
continue;
|
|
|
|
CallInst *CI = dyn_cast<CallInst>(&*RI);
|
|
if (CI && CI->use_empty() && TLI->mayBeEmittedAsTailCall(CI))
|
|
TailCalls.push_back(CI);
|
|
}
|
|
}
|
|
|
|
bool Changed = false;
|
|
for (unsigned i = 0, e = TailCalls.size(); i != e; ++i) {
|
|
CallInst *CI = TailCalls[i];
|
|
CallSite CS(CI);
|
|
|
|
// Conservatively require the attributes of the call to match those of the
|
|
// return. Ignore noalias because it doesn't affect the call sequence.
|
|
AttributeSet CalleeAttrs = CS.getAttributes();
|
|
if (AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
|
|
removeAttribute(Attribute::NoAlias) !=
|
|
AttrBuilder(CalleeAttrs, AttributeSet::ReturnIndex).
|
|
removeAttribute(Attribute::NoAlias))
|
|
continue;
|
|
|
|
// Make sure the call instruction is followed by an unconditional branch to
|
|
// the return block.
|
|
BasicBlock *CallBB = CI->getParent();
|
|
BranchInst *BI = dyn_cast<BranchInst>(CallBB->getTerminator());
|
|
if (!BI || !BI->isUnconditional() || BI->getSuccessor(0) != BB)
|
|
continue;
|
|
|
|
// Duplicate the return into CallBB.
|
|
(void)FoldReturnIntoUncondBranch(RI, BB, CallBB);
|
|
ModifiedDT = Changed = true;
|
|
++NumRetsDup;
|
|
}
|
|
|
|
// If we eliminated all predecessors of the block, delete the block now.
|
|
if (Changed && !BB->hasAddressTaken() && pred_begin(BB) == pred_end(BB))
|
|
BB->eraseFromParent();
|
|
|
|
return Changed;
|
|
}
|
|
|
|
//===----------------------------------------------------------------------===//
|
|
// Memory Optimization
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
namespace {
|
|
|
|
/// ExtAddrMode - This is an extended version of TargetLowering::AddrMode
|
|
/// which holds actual Value*'s for register values.
|
|
struct ExtAddrMode : public TargetLowering::AddrMode {
|
|
Value *BaseReg;
|
|
Value *ScaledReg;
|
|
ExtAddrMode() : BaseReg(nullptr), ScaledReg(nullptr) {}
|
|
void print(raw_ostream &OS) const;
|
|
void dump() const;
|
|
|
|
bool operator==(const ExtAddrMode& O) const {
|
|
return (BaseReg == O.BaseReg) && (ScaledReg == O.ScaledReg) &&
|
|
(BaseGV == O.BaseGV) && (BaseOffs == O.BaseOffs) &&
|
|
(HasBaseReg == O.HasBaseReg) && (Scale == O.Scale);
|
|
}
|
|
};
|
|
|
|
#ifndef NDEBUG
|
|
static inline raw_ostream &operator<<(raw_ostream &OS, const ExtAddrMode &AM) {
|
|
AM.print(OS);
|
|
return OS;
|
|
}
|
|
#endif
|
|
|
|
void ExtAddrMode::print(raw_ostream &OS) const {
|
|
bool NeedPlus = false;
|
|
OS << "[";
|
|
if (BaseGV) {
|
|
OS << (NeedPlus ? " + " : "")
|
|
<< "GV:";
|
|
BaseGV->printAsOperand(OS, /*PrintType=*/false);
|
|
NeedPlus = true;
|
|
}
|
|
|
|
if (BaseOffs) {
|
|
OS << (NeedPlus ? " + " : "")
|
|
<< BaseOffs;
|
|
NeedPlus = true;
|
|
}
|
|
|
|
if (BaseReg) {
|
|
OS << (NeedPlus ? " + " : "")
|
|
<< "Base:";
|
|
BaseReg->printAsOperand(OS, /*PrintType=*/false);
|
|
NeedPlus = true;
|
|
}
|
|
if (Scale) {
|
|
OS << (NeedPlus ? " + " : "")
|
|
<< Scale << "*";
|
|
ScaledReg->printAsOperand(OS, /*PrintType=*/false);
|
|
}
|
|
|
|
OS << ']';
|
|
}
|
|
|
|
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
|
|
void ExtAddrMode::dump() const {
|
|
print(dbgs());
|
|
dbgs() << '\n';
|
|
}
|
|
#endif
|
|
|
|
/// \brief This class provides transaction based operation on the IR.
|
|
/// Every change made through this class is recorded in the internal state and
|
|
/// can be undone (rollback) until commit is called.
|
|
class TypePromotionTransaction {
|
|
|
|
/// \brief This represents the common interface of the individual transaction.
|
|
/// Each class implements the logic for doing one specific modification on
|
|
/// the IR via the TypePromotionTransaction.
|
|
class TypePromotionAction {
|
|
protected:
|
|
/// The Instruction modified.
|
|
Instruction *Inst;
|
|
|
|
public:
|
|
/// \brief Constructor of the action.
|
|
/// The constructor performs the related action on the IR.
|
|
TypePromotionAction(Instruction *Inst) : Inst(Inst) {}
|
|
|
|
virtual ~TypePromotionAction() {}
|
|
|
|
/// \brief Undo the modification done by this action.
|
|
/// When this method is called, the IR must be in the same state as it was
|
|
/// before this action was applied.
|
|
/// \pre Undoing the action works if and only if the IR is in the exact same
|
|
/// state as it was directly after this action was applied.
|
|
virtual void undo() = 0;
|
|
|
|
/// \brief Advocate every change made by this action.
|
|
/// When the results on the IR of the action are to be kept, it is important
|
|
/// to call this function, otherwise hidden information may be kept forever.
|
|
virtual void commit() {
|
|
// Nothing to be done, this action is not doing anything.
|
|
}
|
|
};
|
|
|
|
/// \brief Utility to remember the position of an instruction.
|
|
class InsertionHandler {
|
|
/// Position of an instruction.
|
|
/// Either an instruction:
|
|
/// - Is the first in a basic block: BB is used.
|
|
/// - Has a previous instructon: PrevInst is used.
|
|
union {
|
|
Instruction *PrevInst;
|
|
BasicBlock *BB;
|
|
} Point;
|
|
/// Remember whether or not the instruction had a previous instruction.
|
|
bool HasPrevInstruction;
|
|
|
|
public:
|
|
/// \brief Record the position of \p Inst.
|
|
InsertionHandler(Instruction *Inst) {
|
|
BasicBlock::iterator It = Inst;
|
|
HasPrevInstruction = (It != (Inst->getParent()->begin()));
|
|
if (HasPrevInstruction)
|
|
Point.PrevInst = --It;
|
|
else
|
|
Point.BB = Inst->getParent();
|
|
}
|
|
|
|
/// \brief Insert \p Inst at the recorded position.
|
|
void insert(Instruction *Inst) {
|
|
if (HasPrevInstruction) {
|
|
if (Inst->getParent())
|
|
Inst->removeFromParent();
|
|
Inst->insertAfter(Point.PrevInst);
|
|
} else {
|
|
Instruction *Position = Point.BB->getFirstInsertionPt();
|
|
if (Inst->getParent())
|
|
Inst->moveBefore(Position);
|
|
else
|
|
Inst->insertBefore(Position);
|
|
}
|
|
}
|
|
};
|
|
|
|
/// \brief Move an instruction before another.
|
|
class InstructionMoveBefore : public TypePromotionAction {
|
|
/// Original position of the instruction.
|
|
InsertionHandler Position;
|
|
|
|
public:
|
|
/// \brief Move \p Inst before \p Before.
|
|
InstructionMoveBefore(Instruction *Inst, Instruction *Before)
|
|
: TypePromotionAction(Inst), Position(Inst) {
|
|
DEBUG(dbgs() << "Do: move: " << *Inst << "\nbefore: " << *Before << "\n");
|
|
Inst->moveBefore(Before);
|
|
}
|
|
|
|
/// \brief Move the instruction back to its original position.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: moveBefore: " << *Inst << "\n");
|
|
Position.insert(Inst);
|
|
}
|
|
};
|
|
|
|
/// \brief Set the operand of an instruction with a new value.
|
|
class OperandSetter : public TypePromotionAction {
|
|
/// Original operand of the instruction.
|
|
Value *Origin;
|
|
/// Index of the modified instruction.
|
|
unsigned Idx;
|
|
|
|
public:
|
|
/// \brief Set \p Idx operand of \p Inst with \p NewVal.
|
|
OperandSetter(Instruction *Inst, unsigned Idx, Value *NewVal)
|
|
: TypePromotionAction(Inst), Idx(Idx) {
|
|
DEBUG(dbgs() << "Do: setOperand: " << Idx << "\n"
|
|
<< "for:" << *Inst << "\n"
|
|
<< "with:" << *NewVal << "\n");
|
|
Origin = Inst->getOperand(Idx);
|
|
Inst->setOperand(Idx, NewVal);
|
|
}
|
|
|
|
/// \brief Restore the original value of the instruction.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: setOperand:" << Idx << "\n"
|
|
<< "for: " << *Inst << "\n"
|
|
<< "with: " << *Origin << "\n");
|
|
Inst->setOperand(Idx, Origin);
|
|
}
|
|
};
|
|
|
|
/// \brief Hide the operands of an instruction.
|
|
/// Do as if this instruction was not using any of its operands.
|
|
class OperandsHider : public TypePromotionAction {
|
|
/// The list of original operands.
|
|
SmallVector<Value *, 4> OriginalValues;
|
|
|
|
public:
|
|
/// \brief Remove \p Inst from the uses of the operands of \p Inst.
|
|
OperandsHider(Instruction *Inst) : TypePromotionAction(Inst) {
|
|
DEBUG(dbgs() << "Do: OperandsHider: " << *Inst << "\n");
|
|
unsigned NumOpnds = Inst->getNumOperands();
|
|
OriginalValues.reserve(NumOpnds);
|
|
for (unsigned It = 0; It < NumOpnds; ++It) {
|
|
// Save the current operand.
|
|
Value *Val = Inst->getOperand(It);
|
|
OriginalValues.push_back(Val);
|
|
// Set a dummy one.
|
|
// We could use OperandSetter here, but that would implied an overhead
|
|
// that we are not willing to pay.
|
|
Inst->setOperand(It, UndefValue::get(Val->getType()));
|
|
}
|
|
}
|
|
|
|
/// \brief Restore the original list of uses.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: OperandsHider: " << *Inst << "\n");
|
|
for (unsigned It = 0, EndIt = OriginalValues.size(); It != EndIt; ++It)
|
|
Inst->setOperand(It, OriginalValues[It]);
|
|
}
|
|
};
|
|
|
|
/// \brief Build a truncate instruction.
|
|
class TruncBuilder : public TypePromotionAction {
|
|
Value *Val;
|
|
public:
|
|
/// \brief Build a truncate instruction of \p Opnd producing a \p Ty
|
|
/// result.
|
|
/// trunc Opnd to Ty.
|
|
TruncBuilder(Instruction *Opnd, Type *Ty) : TypePromotionAction(Opnd) {
|
|
IRBuilder<> Builder(Opnd);
|
|
Val = Builder.CreateTrunc(Opnd, Ty, "promoted");
|
|
DEBUG(dbgs() << "Do: TruncBuilder: " << *Val << "\n");
|
|
}
|
|
|
|
/// \brief Get the built value.
|
|
Value *getBuiltValue() { return Val; }
|
|
|
|
/// \brief Remove the built instruction.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: TruncBuilder: " << *Val << "\n");
|
|
if (Instruction *IVal = dyn_cast<Instruction>(Val))
|
|
IVal->eraseFromParent();
|
|
}
|
|
};
|
|
|
|
/// \brief Build a sign extension instruction.
|
|
class SExtBuilder : public TypePromotionAction {
|
|
Value *Val;
|
|
public:
|
|
/// \brief Build a sign extension instruction of \p Opnd producing a \p Ty
|
|
/// result.
|
|
/// sext Opnd to Ty.
|
|
SExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
|
|
: TypePromotionAction(InsertPt) {
|
|
IRBuilder<> Builder(InsertPt);
|
|
Val = Builder.CreateSExt(Opnd, Ty, "promoted");
|
|
DEBUG(dbgs() << "Do: SExtBuilder: " << *Val << "\n");
|
|
}
|
|
|
|
/// \brief Get the built value.
|
|
Value *getBuiltValue() { return Val; }
|
|
|
|
/// \brief Remove the built instruction.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: SExtBuilder: " << *Val << "\n");
|
|
if (Instruction *IVal = dyn_cast<Instruction>(Val))
|
|
IVal->eraseFromParent();
|
|
}
|
|
};
|
|
|
|
/// \brief Build a zero extension instruction.
|
|
class ZExtBuilder : public TypePromotionAction {
|
|
Value *Val;
|
|
public:
|
|
/// \brief Build a zero extension instruction of \p Opnd producing a \p Ty
|
|
/// result.
|
|
/// zext Opnd to Ty.
|
|
ZExtBuilder(Instruction *InsertPt, Value *Opnd, Type *Ty)
|
|
: TypePromotionAction(InsertPt) {
|
|
IRBuilder<> Builder(InsertPt);
|
|
Val = Builder.CreateZExt(Opnd, Ty, "promoted");
|
|
DEBUG(dbgs() << "Do: ZExtBuilder: " << *Val << "\n");
|
|
}
|
|
|
|
/// \brief Get the built value.
|
|
Value *getBuiltValue() { return Val; }
|
|
|
|
/// \brief Remove the built instruction.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: ZExtBuilder: " << *Val << "\n");
|
|
if (Instruction *IVal = dyn_cast<Instruction>(Val))
|
|
IVal->eraseFromParent();
|
|
}
|
|
};
|
|
|
|
/// \brief Mutate an instruction to another type.
|
|
class TypeMutator : public TypePromotionAction {
|
|
/// Record the original type.
|
|
Type *OrigTy;
|
|
|
|
public:
|
|
/// \brief Mutate the type of \p Inst into \p NewTy.
|
|
TypeMutator(Instruction *Inst, Type *NewTy)
|
|
: TypePromotionAction(Inst), OrigTy(Inst->getType()) {
|
|
DEBUG(dbgs() << "Do: MutateType: " << *Inst << " with " << *NewTy
|
|
<< "\n");
|
|
Inst->mutateType(NewTy);
|
|
}
|
|
|
|
/// \brief Mutate the instruction back to its original type.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: MutateType: " << *Inst << " with " << *OrigTy
|
|
<< "\n");
|
|
Inst->mutateType(OrigTy);
|
|
}
|
|
};
|
|
|
|
/// \brief Replace the uses of an instruction by another instruction.
|
|
class UsesReplacer : public TypePromotionAction {
|
|
/// Helper structure to keep track of the replaced uses.
|
|
struct InstructionAndIdx {
|
|
/// The instruction using the instruction.
|
|
Instruction *Inst;
|
|
/// The index where this instruction is used for Inst.
|
|
unsigned Idx;
|
|
InstructionAndIdx(Instruction *Inst, unsigned Idx)
|
|
: Inst(Inst), Idx(Idx) {}
|
|
};
|
|
|
|
/// Keep track of the original uses (pair Instruction, Index).
|
|
SmallVector<InstructionAndIdx, 4> OriginalUses;
|
|
typedef SmallVectorImpl<InstructionAndIdx>::iterator use_iterator;
|
|
|
|
public:
|
|
/// \brief Replace all the use of \p Inst by \p New.
|
|
UsesReplacer(Instruction *Inst, Value *New) : TypePromotionAction(Inst) {
|
|
DEBUG(dbgs() << "Do: UsersReplacer: " << *Inst << " with " << *New
|
|
<< "\n");
|
|
// Record the original uses.
|
|
for (Use &U : Inst->uses()) {
|
|
Instruction *UserI = cast<Instruction>(U.getUser());
|
|
OriginalUses.push_back(InstructionAndIdx(UserI, U.getOperandNo()));
|
|
}
|
|
// Now, we can replace the uses.
|
|
Inst->replaceAllUsesWith(New);
|
|
}
|
|
|
|
/// \brief Reassign the original uses of Inst to Inst.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: UsersReplacer: " << *Inst << "\n");
|
|
for (use_iterator UseIt = OriginalUses.begin(),
|
|
EndIt = OriginalUses.end();
|
|
UseIt != EndIt; ++UseIt) {
|
|
UseIt->Inst->setOperand(UseIt->Idx, Inst);
|
|
}
|
|
}
|
|
};
|
|
|
|
/// \brief Remove an instruction from the IR.
|
|
class InstructionRemover : public TypePromotionAction {
|
|
/// Original position of the instruction.
|
|
InsertionHandler Inserter;
|
|
/// Helper structure to hide all the link to the instruction. In other
|
|
/// words, this helps to do as if the instruction was removed.
|
|
OperandsHider Hider;
|
|
/// Keep track of the uses replaced, if any.
|
|
UsesReplacer *Replacer;
|
|
|
|
public:
|
|
/// \brief Remove all reference of \p Inst and optinally replace all its
|
|
/// uses with New.
|
|
/// \pre If !Inst->use_empty(), then New != nullptr
|
|
InstructionRemover(Instruction *Inst, Value *New = nullptr)
|
|
: TypePromotionAction(Inst), Inserter(Inst), Hider(Inst),
|
|
Replacer(nullptr) {
|
|
if (New)
|
|
Replacer = new UsesReplacer(Inst, New);
|
|
DEBUG(dbgs() << "Do: InstructionRemover: " << *Inst << "\n");
|
|
Inst->removeFromParent();
|
|
}
|
|
|
|
~InstructionRemover() { delete Replacer; }
|
|
|
|
/// \brief Really remove the instruction.
|
|
void commit() override { delete Inst; }
|
|
|
|
/// \brief Resurrect the instruction and reassign it to the proper uses if
|
|
/// new value was provided when build this action.
|
|
void undo() override {
|
|
DEBUG(dbgs() << "Undo: InstructionRemover: " << *Inst << "\n");
|
|
Inserter.insert(Inst);
|
|
if (Replacer)
|
|
Replacer->undo();
|
|
Hider.undo();
|
|
}
|
|
};
|
|
|
|
public:
|
|
/// Restoration point.
|
|
/// The restoration point is a pointer to an action instead of an iterator
|
|
/// because the iterator may be invalidated but not the pointer.
|
|
typedef const TypePromotionAction *ConstRestorationPt;
|
|
/// Advocate every changes made in that transaction.
|
|
void commit();
|
|
/// Undo all the changes made after the given point.
|
|
void rollback(ConstRestorationPt Point);
|
|
/// Get the current restoration point.
|
|
ConstRestorationPt getRestorationPoint() const;
|
|
|
|
/// \name API for IR modification with state keeping to support rollback.
|
|
/// @{
|
|
/// Same as Instruction::setOperand.
|
|
void setOperand(Instruction *Inst, unsigned Idx, Value *NewVal);
|
|
/// Same as Instruction::eraseFromParent.
|
|
void eraseInstruction(Instruction *Inst, Value *NewVal = nullptr);
|
|
/// Same as Value::replaceAllUsesWith.
|
|
void replaceAllUsesWith(Instruction *Inst, Value *New);
|
|
/// Same as Value::mutateType.
|
|
void mutateType(Instruction *Inst, Type *NewTy);
|
|
/// Same as IRBuilder::createTrunc.
|
|
Value *createTrunc(Instruction *Opnd, Type *Ty);
|
|
/// Same as IRBuilder::createSExt.
|
|
Value *createSExt(Instruction *Inst, Value *Opnd, Type *Ty);
|
|
/// Same as IRBuilder::createZExt.
|
|
Value *createZExt(Instruction *Inst, Value *Opnd, Type *Ty);
|
|
/// Same as Instruction::moveBefore.
|
|
void moveBefore(Instruction *Inst, Instruction *Before);
|
|
/// @}
|
|
|
|
private:
|
|
/// The ordered list of actions made so far.
|
|
SmallVector<std::unique_ptr<TypePromotionAction>, 16> Actions;
|
|
typedef SmallVectorImpl<std::unique_ptr<TypePromotionAction>>::iterator CommitPt;
|
|
};
|
|
|
|
void TypePromotionTransaction::setOperand(Instruction *Inst, unsigned Idx,
|
|
Value *NewVal) {
|
|
Actions.push_back(
|
|
make_unique<TypePromotionTransaction::OperandSetter>(Inst, Idx, NewVal));
|
|
}
|
|
|
|
void TypePromotionTransaction::eraseInstruction(Instruction *Inst,
|
|
Value *NewVal) {
|
|
Actions.push_back(
|
|
make_unique<TypePromotionTransaction::InstructionRemover>(Inst, NewVal));
|
|
}
|
|
|
|
void TypePromotionTransaction::replaceAllUsesWith(Instruction *Inst,
|
|
Value *New) {
|
|
Actions.push_back(make_unique<TypePromotionTransaction::UsesReplacer>(Inst, New));
|
|
}
|
|
|
|
void TypePromotionTransaction::mutateType(Instruction *Inst, Type *NewTy) {
|
|
Actions.push_back(make_unique<TypePromotionTransaction::TypeMutator>(Inst, NewTy));
|
|
}
|
|
|
|
Value *TypePromotionTransaction::createTrunc(Instruction *Opnd,
|
|
Type *Ty) {
|
|
std::unique_ptr<TruncBuilder> Ptr(new TruncBuilder(Opnd, Ty));
|
|
Value *Val = Ptr->getBuiltValue();
|
|
Actions.push_back(std::move(Ptr));
|
|
return Val;
|
|
}
|
|
|
|
Value *TypePromotionTransaction::createSExt(Instruction *Inst,
|
|
Value *Opnd, Type *Ty) {
|
|
std::unique_ptr<SExtBuilder> Ptr(new SExtBuilder(Inst, Opnd, Ty));
|
|
Value *Val = Ptr->getBuiltValue();
|
|
Actions.push_back(std::move(Ptr));
|
|
return Val;
|
|
}
|
|
|
|
Value *TypePromotionTransaction::createZExt(Instruction *Inst,
|
|
Value *Opnd, Type *Ty) {
|
|
std::unique_ptr<ZExtBuilder> Ptr(new ZExtBuilder(Inst, Opnd, Ty));
|
|
Value *Val = Ptr->getBuiltValue();
|
|
Actions.push_back(std::move(Ptr));
|
|
return Val;
|
|
}
|
|
|
|
void TypePromotionTransaction::moveBefore(Instruction *Inst,
|
|
Instruction *Before) {
|
|
Actions.push_back(
|
|
make_unique<TypePromotionTransaction::InstructionMoveBefore>(Inst, Before));
|
|
}
|
|
|
|
TypePromotionTransaction::ConstRestorationPt
|
|
TypePromotionTransaction::getRestorationPoint() const {
|
|
return !Actions.empty() ? Actions.back().get() : nullptr;
|
|
}
|
|
|
|
void TypePromotionTransaction::commit() {
|
|
for (CommitPt It = Actions.begin(), EndIt = Actions.end(); It != EndIt;
|
|
++It)
|
|
(*It)->commit();
|
|
Actions.clear();
|
|
}
|
|
|
|
void TypePromotionTransaction::rollback(
|
|
TypePromotionTransaction::ConstRestorationPt Point) {
|
|
while (!Actions.empty() && Point != Actions.back().get()) {
|
|
std::unique_ptr<TypePromotionAction> Curr = Actions.pop_back_val();
|
|
Curr->undo();
|
|
}
|
|
}
|
|
|
|
/// \brief A helper class for matching addressing modes.
|
|
///
|
|
/// This encapsulates the logic for matching the target-legal addressing modes.
|
|
class AddressingModeMatcher {
|
|
SmallVectorImpl<Instruction*> &AddrModeInsts;
|
|
const TargetMachine &TM;
|
|
const TargetLowering &TLI;
|
|
|
|
/// AccessTy/MemoryInst - This is the type for the access (e.g. double) and
|
|
/// the memory instruction that we're computing this address for.
|
|
Type *AccessTy;
|
|
Instruction *MemoryInst;
|
|
|
|
/// AddrMode - This is the addressing mode that we're building up. This is
|
|
/// part of the return value of this addressing mode matching stuff.
|
|
ExtAddrMode &AddrMode;
|
|
|
|
/// The truncate instruction inserted by other CodeGenPrepare optimizations.
|
|
const SetOfInstrs &InsertedTruncs;
|
|
/// A map from the instructions to their type before promotion.
|
|
InstrToOrigTy &PromotedInsts;
|
|
/// The ongoing transaction where every action should be registered.
|
|
TypePromotionTransaction &TPT;
|
|
|
|
/// IgnoreProfitability - This is set to true when we should not do
|
|
/// profitability checks. When true, IsProfitableToFoldIntoAddressingMode
|
|
/// always returns true.
|
|
bool IgnoreProfitability;
|
|
|
|
AddressingModeMatcher(SmallVectorImpl<Instruction *> &AMI,
|
|
const TargetMachine &TM, Type *AT, Instruction *MI,
|
|
ExtAddrMode &AM, const SetOfInstrs &InsertedTruncs,
|
|
InstrToOrigTy &PromotedInsts,
|
|
TypePromotionTransaction &TPT)
|
|
: AddrModeInsts(AMI), TM(TM),
|
|
TLI(*TM.getSubtargetImpl(*MI->getParent()->getParent())
|
|
->getTargetLowering()),
|
|
AccessTy(AT), MemoryInst(MI), AddrMode(AM),
|
|
InsertedTruncs(InsertedTruncs), PromotedInsts(PromotedInsts), TPT(TPT) {
|
|
IgnoreProfitability = false;
|
|
}
|
|
public:
|
|
|
|
/// Match - Find the maximal addressing mode that a load/store of V can fold,
|
|
/// give an access type of AccessTy. This returns a list of involved
|
|
/// instructions in AddrModeInsts.
|
|
/// \p InsertedTruncs The truncate instruction inserted by other
|
|
/// CodeGenPrepare
|
|
/// optimizations.
|
|
/// \p PromotedInsts maps the instructions to their type before promotion.
|
|
/// \p The ongoing transaction where every action should be registered.
|
|
static ExtAddrMode Match(Value *V, Type *AccessTy,
|
|
Instruction *MemoryInst,
|
|
SmallVectorImpl<Instruction*> &AddrModeInsts,
|
|
const TargetMachine &TM,
|
|
const SetOfInstrs &InsertedTruncs,
|
|
InstrToOrigTy &PromotedInsts,
|
|
TypePromotionTransaction &TPT) {
|
|
ExtAddrMode Result;
|
|
|
|
bool Success = AddressingModeMatcher(AddrModeInsts, TM, AccessTy,
|
|
MemoryInst, Result, InsertedTruncs,
|
|
PromotedInsts, TPT).MatchAddr(V, 0);
|
|
(void)Success; assert(Success && "Couldn't select *anything*?");
|
|
return Result;
|
|
}
|
|
private:
|
|
bool MatchScaledValue(Value *ScaleReg, int64_t Scale, unsigned Depth);
|
|
bool MatchAddr(Value *V, unsigned Depth);
|
|
bool MatchOperationAddr(User *Operation, unsigned Opcode, unsigned Depth,
|
|
bool *MovedAway = nullptr);
|
|
bool IsProfitableToFoldIntoAddressingMode(Instruction *I,
|
|
ExtAddrMode &AMBefore,
|
|
ExtAddrMode &AMAfter);
|
|
bool ValueAlreadyLiveAtInst(Value *Val, Value *KnownLive1, Value *KnownLive2);
|
|
bool IsPromotionProfitable(unsigned MatchedSize, unsigned SizeWithPromotion,
|
|
Value *PromotedOperand) const;
|
|
};
|
|
|
|
/// MatchScaledValue - Try adding ScaleReg*Scale to the current addressing mode.
|
|
/// Return true and update AddrMode if this addr mode is legal for the target,
|
|
/// false if not.
|
|
bool AddressingModeMatcher::MatchScaledValue(Value *ScaleReg, int64_t Scale,
|
|
unsigned Depth) {
|
|
// If Scale is 1, then this is the same as adding ScaleReg to the addressing
|
|
// mode. Just process that directly.
|
|
if (Scale == 1)
|
|
return MatchAddr(ScaleReg, Depth);
|
|
|
|
// If the scale is 0, it takes nothing to add this.
|
|
if (Scale == 0)
|
|
return true;
|
|
|
|
// If we already have a scale of this value, we can add to it, otherwise, we
|
|
// need an available scale field.
|
|
if (AddrMode.Scale != 0 && AddrMode.ScaledReg != ScaleReg)
|
|
return false;
|
|
|
|
ExtAddrMode TestAddrMode = AddrMode;
|
|
|
|
// Add scale to turn X*4+X*3 -> X*7. This could also do things like
|
|
// [A+B + A*7] -> [B+A*8].
|
|
TestAddrMode.Scale += Scale;
|
|
TestAddrMode.ScaledReg = ScaleReg;
|
|
|
|
// If the new address isn't legal, bail out.
|
|
if (!TLI.isLegalAddressingMode(TestAddrMode, AccessTy))
|
|
return false;
|
|
|
|
// It was legal, so commit it.
|
|
AddrMode = TestAddrMode;
|
|
|
|
// Okay, we decided that we can add ScaleReg+Scale to AddrMode. Check now
|
|
// to see if ScaleReg is actually X+C. If so, we can turn this into adding
|
|
// X*Scale + C*Scale to addr mode.
|
|
ConstantInt *CI = nullptr; Value *AddLHS = nullptr;
|
|
if (isa<Instruction>(ScaleReg) && // not a constant expr.
|
|
match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
|
|
TestAddrMode.ScaledReg = AddLHS;
|
|
TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
|
|
|
|
// If this addressing mode is legal, commit it and remember that we folded
|
|
// this instruction.
|
|
if (TLI.isLegalAddressingMode(TestAddrMode, AccessTy)) {
|
|
AddrModeInsts.push_back(cast<Instruction>(ScaleReg));
|
|
AddrMode = TestAddrMode;
|
|
return true;
|
|
}
|
|
}
|
|
|
|
// Otherwise, not (x+c)*scale, just return what we have.
|
|
return true;
|
|
}
|
|
|
|
/// MightBeFoldableInst - This is a little filter, which returns true if an
|
|
/// addressing computation involving I might be folded into a load/store
|
|
/// accessing it. This doesn't need to be perfect, but needs to accept at least
|
|
/// the set of instructions that MatchOperationAddr can.
|
|
static bool MightBeFoldableInst(Instruction *I) {
|
|
switch (I->getOpcode()) {
|
|
case Instruction::BitCast:
|
|
case Instruction::AddrSpaceCast:
|
|
// Don't touch identity bitcasts.
|
|
if (I->getType() == I->getOperand(0)->getType())
|
|
return false;
|
|
return I->getType()->isPointerTy() || I->getType()->isIntegerTy();
|
|
case Instruction::PtrToInt:
|
|
// PtrToInt is always a noop, as we know that the int type is pointer sized.
|
|
return true;
|
|
case Instruction::IntToPtr:
|
|
// We know the input is intptr_t, so this is foldable.
|
|
return true;
|
|
case Instruction::Add:
|
|
return true;
|
|
case Instruction::Mul:
|
|
case Instruction::Shl:
|
|
// Can only handle X*C and X << C.
|
|
return isa<ConstantInt>(I->getOperand(1));
|
|
case Instruction::GetElementPtr:
|
|
return true;
|
|
default:
|
|
return false;
|
|
}
|
|
}
|
|
|
|
/// \brief Check whether or not \p Val is a legal instruction for \p TLI.
|
|
/// \note \p Val is assumed to be the product of some type promotion.
|
|
/// Therefore if \p Val has an undefined state in \p TLI, this is assumed
|
|
/// to be legal, as the non-promoted value would have had the same state.
|
|
static bool isPromotedInstructionLegal(const TargetLowering &TLI, Value *Val) {
|
|
Instruction *PromotedInst = dyn_cast<Instruction>(Val);
|
|
if (!PromotedInst)
|
|
return false;
|
|
int ISDOpcode = TLI.InstructionOpcodeToISD(PromotedInst->getOpcode());
|
|
// If the ISDOpcode is undefined, it was undefined before the promotion.
|
|
if (!ISDOpcode)
|
|
return true;
|
|
// Otherwise, check if the promoted instruction is legal or not.
|
|
return TLI.isOperationLegalOrCustom(
|
|
ISDOpcode, TLI.getValueType(PromotedInst->getType()));
|
|
}
|
|
|
|
/// \brief Hepler class to perform type promotion.
|
|
class TypePromotionHelper {
|
|
/// \brief Utility function to check whether or not a sign or zero extension
|
|
/// of \p Inst with \p ConsideredExtType can be moved through \p Inst by
|
|
/// either using the operands of \p Inst or promoting \p Inst.
|
|
/// The type of the extension is defined by \p IsSExt.
|
|
/// In other words, check if:
|
|
/// ext (Ty Inst opnd1 opnd2 ... opndN) to ConsideredExtType.
|
|
/// #1 Promotion applies:
|
|
/// ConsideredExtType Inst (ext opnd1 to ConsideredExtType, ...).
|
|
/// #2 Operand reuses:
|
|
/// ext opnd1 to ConsideredExtType.
|
|
/// \p PromotedInsts maps the instructions to their type before promotion.
|
|
static bool canGetThrough(const Instruction *Inst, Type *ConsideredExtType,
|
|
const InstrToOrigTy &PromotedInsts, bool IsSExt);
|
|
|
|
/// \brief Utility function to determine if \p OpIdx should be promoted when
|
|
/// promoting \p Inst.
|
|
static bool shouldExtOperand(const Instruction *Inst, int OpIdx) {
|
|
if (isa<SelectInst>(Inst) && OpIdx == 0)
|
|
return false;
|
|
return true;
|
|
}
|
|
|
|
/// \brief Utility function to promote the operand of \p Ext when this
|
|
/// operand is a promotable trunc or sext or zext.
|
|
/// \p PromotedInsts maps the instructions to their type before promotion.
|
|
/// \p CreatedInsts[out] contains how many non-free instructions have been
|
|
/// created to promote the operand of Ext.
|
|
/// Newly added extensions are inserted in \p Exts.
|
|
/// Newly added truncates are inserted in \p Truncs.
|
|
/// Should never be called directly.
|
|
/// \return The promoted value which is used instead of Ext.
|
|
static Value *promoteOperandForTruncAndAnyExt(
|
|
Instruction *Ext, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs);
|
|
|
|
/// \brief Utility function to promote the operand of \p Ext when this
|
|
/// operand is promotable and is not a supported trunc or sext.
|
|
/// \p PromotedInsts maps the instructions to their type before promotion.
|
|
/// \p CreatedInsts[out] contains how many non-free instructions have been
|
|
/// created to promote the operand of Ext.
|
|
/// Newly added extensions are inserted in \p Exts.
|
|
/// Newly added truncates are inserted in \p Truncs.
|
|
/// Should never be called directly.
|
|
/// \return The promoted value which is used instead of Ext.
|
|
static Value *
|
|
promoteOperandForOther(Instruction *Ext, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs, bool IsSExt);
|
|
|
|
/// \see promoteOperandForOther.
|
|
static Value *
|
|
signExtendOperandForOther(Instruction *Ext, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts,
|
|
unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs) {
|
|
return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInsts, Exts,
|
|
Truncs, true);
|
|
}
|
|
|
|
/// \see promoteOperandForOther.
|
|
static Value *
|
|
zeroExtendOperandForOther(Instruction *Ext, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts,
|
|
unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs) {
|
|
return promoteOperandForOther(Ext, TPT, PromotedInsts, CreatedInsts, Exts,
|
|
Truncs, false);
|
|
}
|
|
|
|
public:
|
|
/// Type for the utility function that promotes the operand of Ext.
|
|
typedef Value *(*Action)(Instruction *Ext, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs);
|
|
/// \brief Given a sign/zero extend instruction \p Ext, return the approriate
|
|
/// action to promote the operand of \p Ext instead of using Ext.
|
|
/// \return NULL if no promotable action is possible with the current
|
|
/// sign extension.
|
|
/// \p InsertedTruncs keeps track of all the truncate instructions inserted by
|
|
/// the others CodeGenPrepare optimizations. This information is important
|
|
/// because we do not want to promote these instructions as CodeGenPrepare
|
|
/// will reinsert them later. Thus creating an infinite loop: create/remove.
|
|
/// \p PromotedInsts maps the instructions to their type before promotion.
|
|
static Action getAction(Instruction *Ext, const SetOfInstrs &InsertedTruncs,
|
|
const TargetLowering &TLI,
|
|
const InstrToOrigTy &PromotedInsts);
|
|
};
|
|
|
|
bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
|
|
Type *ConsideredExtType,
|
|
const InstrToOrigTy &PromotedInsts,
|
|
bool IsSExt) {
|
|
// The promotion helper does not know how to deal with vector types yet.
|
|
// To be able to fix that, we would need to fix the places where we
|
|
// statically extend, e.g., constants and such.
|
|
if (Inst->getType()->isVectorTy())
|
|
return false;
|
|
|
|
// We can always get through zext.
|
|
if (isa<ZExtInst>(Inst))
|
|
return true;
|
|
|
|
// sext(sext) is ok too.
|
|
if (IsSExt && isa<SExtInst>(Inst))
|
|
return true;
|
|
|
|
// We can get through binary operator, if it is legal. In other words, the
|
|
// binary operator must have a nuw or nsw flag.
|
|
const BinaryOperator *BinOp = dyn_cast<BinaryOperator>(Inst);
|
|
if (BinOp && isa<OverflowingBinaryOperator>(BinOp) &&
|
|
((!IsSExt && BinOp->hasNoUnsignedWrap()) ||
|
|
(IsSExt && BinOp->hasNoSignedWrap())))
|
|
return true;
|
|
|
|
// Check if we can do the following simplification.
|
|
// ext(trunc(opnd)) --> ext(opnd)
|
|
if (!isa<TruncInst>(Inst))
|
|
return false;
|
|
|
|
Value *OpndVal = Inst->getOperand(0);
|
|
// Check if we can use this operand in the extension.
|
|
// If the type is larger than the result type of the extension,
|
|
// we cannot.
|
|
if (!OpndVal->getType()->isIntegerTy() ||
|
|
OpndVal->getType()->getIntegerBitWidth() >
|
|
ConsideredExtType->getIntegerBitWidth())
|
|
return false;
|
|
|
|
// If the operand of the truncate is not an instruction, we will not have
|
|
// any information on the dropped bits.
|
|
// (Actually we could for constant but it is not worth the extra logic).
|
|
Instruction *Opnd = dyn_cast<Instruction>(OpndVal);
|
|
if (!Opnd)
|
|
return false;
|
|
|
|
// Check if the source of the type is narrow enough.
|
|
// I.e., check that trunc just drops extended bits of the same kind of
|
|
// the extension.
|
|
// #1 get the type of the operand and check the kind of the extended bits.
|
|
const Type *OpndType;
|
|
InstrToOrigTy::const_iterator It = PromotedInsts.find(Opnd);
|
|
if (It != PromotedInsts.end() && It->second.IsSExt == IsSExt)
|
|
OpndType = It->second.Ty;
|
|
else if ((IsSExt && isa<SExtInst>(Opnd)) || (!IsSExt && isa<ZExtInst>(Opnd)))
|
|
OpndType = Opnd->getOperand(0)->getType();
|
|
else
|
|
return false;
|
|
|
|
// #2 check that the truncate just drop extended bits.
|
|
if (Inst->getType()->getIntegerBitWidth() >= OpndType->getIntegerBitWidth())
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
TypePromotionHelper::Action TypePromotionHelper::getAction(
|
|
Instruction *Ext, const SetOfInstrs &InsertedTruncs,
|
|
const TargetLowering &TLI, const InstrToOrigTy &PromotedInsts) {
|
|
assert((isa<SExtInst>(Ext) || isa<ZExtInst>(Ext)) &&
|
|
"Unexpected instruction type");
|
|
Instruction *ExtOpnd = dyn_cast<Instruction>(Ext->getOperand(0));
|
|
Type *ExtTy = Ext->getType();
|
|
bool IsSExt = isa<SExtInst>(Ext);
|
|
// If the operand of the extension is not an instruction, we cannot
|
|
// get through.
|
|
// If it, check we can get through.
|
|
if (!ExtOpnd || !canGetThrough(ExtOpnd, ExtTy, PromotedInsts, IsSExt))
|
|
return nullptr;
|
|
|
|
// Do not promote if the operand has been added by codegenprepare.
|
|
// Otherwise, it means we are undoing an optimization that is likely to be
|
|
// redone, thus causing potential infinite loop.
|
|
if (isa<TruncInst>(ExtOpnd) && InsertedTruncs.count(ExtOpnd))
|
|
return nullptr;
|
|
|
|
// SExt or Trunc instructions.
|
|
// Return the related handler.
|
|
if (isa<SExtInst>(ExtOpnd) || isa<TruncInst>(ExtOpnd) ||
|
|
isa<ZExtInst>(ExtOpnd))
|
|
return promoteOperandForTruncAndAnyExt;
|
|
|
|
// Regular instruction.
|
|
// Abort early if we will have to insert non-free instructions.
|
|
if (!ExtOpnd->hasOneUse() && !TLI.isTruncateFree(ExtTy, ExtOpnd->getType()))
|
|
return nullptr;
|
|
return IsSExt ? signExtendOperandForOther : zeroExtendOperandForOther;
|
|
}
|
|
|
|
Value *TypePromotionHelper::promoteOperandForTruncAndAnyExt(
|
|
llvm::Instruction *SExt, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs) {
|
|
// By construction, the operand of SExt is an instruction. Otherwise we cannot
|
|
// get through it and this method should not be called.
|
|
Instruction *SExtOpnd = cast<Instruction>(SExt->getOperand(0));
|
|
Value *ExtVal = SExt;
|
|
if (isa<ZExtInst>(SExtOpnd)) {
|
|
// Replace s|zext(zext(opnd))
|
|
// => zext(opnd).
|
|
Value *ZExt =
|
|
TPT.createZExt(SExt, SExtOpnd->getOperand(0), SExt->getType());
|
|
TPT.replaceAllUsesWith(SExt, ZExt);
|
|
TPT.eraseInstruction(SExt);
|
|
ExtVal = ZExt;
|
|
} else {
|
|
// Replace z|sext(trunc(opnd)) or sext(sext(opnd))
|
|
// => z|sext(opnd).
|
|
TPT.setOperand(SExt, 0, SExtOpnd->getOperand(0));
|
|
}
|
|
CreatedInsts = 0;
|
|
|
|
// Remove dead code.
|
|
if (SExtOpnd->use_empty())
|
|
TPT.eraseInstruction(SExtOpnd);
|
|
|
|
// Check if the extension is still needed.
|
|
Instruction *ExtInst = dyn_cast<Instruction>(ExtVal);
|
|
if (!ExtInst || ExtInst->getType() != ExtInst->getOperand(0)->getType()) {
|
|
if (ExtInst && Exts)
|
|
Exts->push_back(ExtInst);
|
|
return ExtVal;
|
|
}
|
|
|
|
// At this point we have: ext ty opnd to ty.
|
|
// Reassign the uses of ExtInst to the opnd and remove ExtInst.
|
|
Value *NextVal = ExtInst->getOperand(0);
|
|
TPT.eraseInstruction(ExtInst, NextVal);
|
|
return NextVal;
|
|
}
|
|
|
|
Value *TypePromotionHelper::promoteOperandForOther(
|
|
Instruction *Ext, TypePromotionTransaction &TPT,
|
|
InstrToOrigTy &PromotedInsts, unsigned &CreatedInsts,
|
|
SmallVectorImpl<Instruction *> *Exts,
|
|
SmallVectorImpl<Instruction *> *Truncs, bool IsSExt) {
|
|
// By construction, the operand of Ext is an instruction. Otherwise we cannot
|
|
// get through it and this method should not be called.
|
|
Instruction *ExtOpnd = cast<Instruction>(Ext->getOperand(0));
|
|
CreatedInsts = 0;
|
|
if (!ExtOpnd->hasOneUse()) {
|
|
// ExtOpnd will be promoted.
|
|
// All its uses, but Ext, will need to use a truncated value of the
|
|
// promoted version.
|
|
// Create the truncate now.
|
|
Value *Trunc = TPT.createTrunc(Ext, ExtOpnd->getType());
|
|
if (Instruction *ITrunc = dyn_cast<Instruction>(Trunc)) {
|
|
ITrunc->removeFromParent();
|
|
// Insert it just after the definition.
|
|
ITrunc->insertAfter(ExtOpnd);
|
|
if (Truncs)
|
|
Truncs->push_back(ITrunc);
|
|
}
|
|
|
|
TPT.replaceAllUsesWith(ExtOpnd, Trunc);
|
|
// Restore the operand of Ext (which has been replace by the previous call
|
|
// to replaceAllUsesWith) to avoid creating a cycle trunc <-> sext.
|
|
TPT.setOperand(Ext, 0, ExtOpnd);
|
|
}
|
|
|
|
// Get through the Instruction:
|
|
// 1. Update its type.
|
|
// 2. Replace the uses of Ext by Inst.
|
|
// 3. Extend each operand that needs to be extended.
|
|
|
|
// Remember the original type of the instruction before promotion.
|
|
// This is useful to know that the high bits are sign extended bits.
|
|
PromotedInsts.insert(std::pair<Instruction *, TypeIsSExt>(
|
|
ExtOpnd, TypeIsSExt(ExtOpnd->getType(), IsSExt)));
|
|
// Step #1.
|
|
TPT.mutateType(ExtOpnd, Ext->getType());
|
|
// Step #2.
|
|
TPT.replaceAllUsesWith(Ext, ExtOpnd);
|
|
// Step #3.
|
|
Instruction *ExtForOpnd = Ext;
|
|
|
|
DEBUG(dbgs() << "Propagate Ext to operands\n");
|
|
for (int OpIdx = 0, EndOpIdx = ExtOpnd->getNumOperands(); OpIdx != EndOpIdx;
|
|
++OpIdx) {
|
|
DEBUG(dbgs() << "Operand:\n" << *(ExtOpnd->getOperand(OpIdx)) << '\n');
|
|
if (ExtOpnd->getOperand(OpIdx)->getType() == Ext->getType() ||
|
|
!shouldExtOperand(ExtOpnd, OpIdx)) {
|
|
DEBUG(dbgs() << "No need to propagate\n");
|
|
continue;
|
|
}
|
|
// Check if we can statically extend the operand.
|
|
Value *Opnd = ExtOpnd->getOperand(OpIdx);
|
|
if (const ConstantInt *Cst = dyn_cast<ConstantInt>(Opnd)) {
|
|
DEBUG(dbgs() << "Statically extend\n");
|
|
unsigned BitWidth = Ext->getType()->getIntegerBitWidth();
|
|
APInt CstVal = IsSExt ? Cst->getValue().sext(BitWidth)
|
|
: Cst->getValue().zext(BitWidth);
|
|
TPT.setOperand(ExtOpnd, OpIdx, ConstantInt::get(Ext->getType(), CstVal));
|
|
continue;
|
|
}
|
|
// UndefValue are typed, so we have to statically sign extend them.
|
|
if (isa<UndefValue>(Opnd)) {
|
|
DEBUG(dbgs() << "Statically extend\n");
|
|
TPT.setOperand(ExtOpnd, OpIdx, UndefValue::get(Ext->getType()));
|
|
continue;
|
|
}
|
|
|
|
// Otherwise we have to explicity sign extend the operand.
|
|
// Check if Ext was reused to extend an operand.
|
|
if (!ExtForOpnd) {
|
|
// If yes, create a new one.
|
|
DEBUG(dbgs() << "More operands to ext\n");
|
|
Value *ValForExtOpnd = IsSExt ? TPT.createSExt(Ext, Opnd, Ext->getType())
|
|
: TPT.createZExt(Ext, Opnd, Ext->getType());
|
|
if (!isa<Instruction>(ValForExtOpnd)) {
|
|
TPT.setOperand(ExtOpnd, OpIdx, ValForExtOpnd);
|
|
continue;
|
|
}
|
|
ExtForOpnd = cast<Instruction>(ValForExtOpnd);
|
|
++CreatedInsts;
|
|
}
|
|
if (Exts)
|
|
Exts->push_back(ExtForOpnd);
|
|
TPT.setOperand(ExtForOpnd, 0, Opnd);
|
|
|
|
// Move the sign extension before the insertion point.
|
|
TPT.moveBefore(ExtForOpnd, ExtOpnd);
|
|
TPT.setOperand(ExtOpnd, OpIdx, ExtForOpnd);
|
|
// If more sext are required, new instructions will have to be created.
|
|
ExtForOpnd = nullptr;
|
|
}
|
|
if (ExtForOpnd == Ext) {
|
|
DEBUG(dbgs() << "Extension is useless now\n");
|
|
TPT.eraseInstruction(Ext);
|
|
}
|
|
return ExtOpnd;
|
|
}
|
|
|
|
/// IsPromotionProfitable - Check whether or not promoting an instruction
|
|
/// to a wider type was profitable.
|
|
/// \p MatchedSize gives the number of instructions that have been matched
|
|
/// in the addressing mode after the promotion was applied.
|
|
/// \p SizeWithPromotion gives the number of created instructions for
|
|
/// the promotion plus the number of instructions that have been
|
|
/// matched in the addressing mode before the promotion.
|
|
/// \p PromotedOperand is the value that has been promoted.
|
|
/// \return True if the promotion is profitable, false otherwise.
|
|
bool
|
|
AddressingModeMatcher::IsPromotionProfitable(unsigned MatchedSize,
|
|
unsigned SizeWithPromotion,
|
|
Value *PromotedOperand) const {
|
|
// We folded less instructions than what we created to promote the operand.
|
|
// This is not profitable.
|
|
if (MatchedSize < SizeWithPromotion)
|
|
return false;
|
|
if (MatchedSize > SizeWithPromotion)
|
|
return true;
|
|
// The promotion is neutral but it may help folding the sign extension in
|
|
// loads for instance.
|
|
// Check that we did not create an illegal instruction.
|
|
return isPromotedInstructionLegal(TLI, PromotedOperand);
|
|
}
|
|
|
|
/// MatchOperationAddr - Given an instruction or constant expr, see if we can
|
|
/// fold the operation into the addressing mode. If so, update the addressing
|
|
/// mode and return true, otherwise return false without modifying AddrMode.
|
|
/// If \p MovedAway is not NULL, it contains the information of whether or
|
|
/// not AddrInst has to be folded into the addressing mode on success.
|
|
/// If \p MovedAway == true, \p AddrInst will not be part of the addressing
|
|
/// because it has been moved away.
|
|
/// Thus AddrInst must not be added in the matched instructions.
|
|
/// This state can happen when AddrInst is a sext, since it may be moved away.
|
|
/// Therefore, AddrInst may not be valid when MovedAway is true and it must
|
|
/// not be referenced anymore.
|
|
bool AddressingModeMatcher::MatchOperationAddr(User *AddrInst, unsigned Opcode,
|
|
unsigned Depth,
|
|
bool *MovedAway) {
|
|
// Avoid exponential behavior on extremely deep expression trees.
|
|
if (Depth >= 5) return false;
|
|
|
|
// By default, all matched instructions stay in place.
|
|
if (MovedAway)
|
|
*MovedAway = false;
|
|
|
|
switch (Opcode) {
|
|
case Instruction::PtrToInt:
|
|
// PtrToInt is always a noop, as we know that the int type is pointer sized.
|
|
return MatchAddr(AddrInst->getOperand(0), Depth);
|
|
case Instruction::IntToPtr:
|
|
// This inttoptr is a no-op if the integer type is pointer sized.
|
|
if (TLI.getValueType(AddrInst->getOperand(0)->getType()) ==
|
|
TLI.getPointerTy(AddrInst->getType()->getPointerAddressSpace()))
|
|
return MatchAddr(AddrInst->getOperand(0), Depth);
|
|
return false;
|
|
case Instruction::BitCast:
|
|
case Instruction::AddrSpaceCast:
|
|
// BitCast is always a noop, and we can handle it as long as it is
|
|
// int->int or pointer->pointer (we don't want int<->fp or something).
|
|
if ((AddrInst->getOperand(0)->getType()->isPointerTy() ||
|
|
AddrInst->getOperand(0)->getType()->isIntegerTy()) &&
|
|
// Don't touch identity bitcasts. These were probably put here by LSR,
|
|
// and we don't want to mess around with them. Assume it knows what it
|
|
// is doing.
|
|
AddrInst->getOperand(0)->getType() != AddrInst->getType())
|
|
return MatchAddr(AddrInst->getOperand(0), Depth);
|
|
return false;
|
|
case Instruction::Add: {
|
|
// Check to see if we can merge in the RHS then the LHS. If so, we win.
|
|
ExtAddrMode BackupAddrMode = AddrMode;
|
|
unsigned OldSize = AddrModeInsts.size();
|
|
// Start a transaction at this point.
|
|
// The LHS may match but not the RHS.
|
|
// Therefore, we need a higher level restoration point to undo partially
|
|
// matched operation.
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
|
|
if (MatchAddr(AddrInst->getOperand(1), Depth+1) &&
|
|
MatchAddr(AddrInst->getOperand(0), Depth+1))
|
|
return true;
|
|
|
|
// Restore the old addr mode info.
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
TPT.rollback(LastKnownGood);
|
|
|
|
// Otherwise this was over-aggressive. Try merging in the LHS then the RHS.
|
|
if (MatchAddr(AddrInst->getOperand(0), Depth+1) &&
|
|
MatchAddr(AddrInst->getOperand(1), Depth+1))
|
|
return true;
|
|
|
|
// Otherwise we definitely can't merge the ADD in.
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
TPT.rollback(LastKnownGood);
|
|
break;
|
|
}
|
|
//case Instruction::Or:
|
|
// TODO: We can handle "Or Val, Imm" iff this OR is equivalent to an ADD.
|
|
//break;
|
|
case Instruction::Mul:
|
|
case Instruction::Shl: {
|
|
// Can only handle X*C and X << C.
|
|
ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
|
|
if (!RHS)
|
|
return false;
|
|
int64_t Scale = RHS->getSExtValue();
|
|
if (Opcode == Instruction::Shl)
|
|
Scale = 1LL << Scale;
|
|
|
|
return MatchScaledValue(AddrInst->getOperand(0), Scale, Depth);
|
|
}
|
|
case Instruction::GetElementPtr: {
|
|
// Scan the GEP. We check it if it contains constant offsets and at most
|
|
// one variable offset.
|
|
int VariableOperand = -1;
|
|
unsigned VariableScale = 0;
|
|
|
|
int64_t ConstantOffset = 0;
|
|
const DataLayout *TD = TLI.getDataLayout();
|
|
gep_type_iterator GTI = gep_type_begin(AddrInst);
|
|
for (unsigned i = 1, e = AddrInst->getNumOperands(); i != e; ++i, ++GTI) {
|
|
if (StructType *STy = dyn_cast<StructType>(*GTI)) {
|
|
const StructLayout *SL = TD->getStructLayout(STy);
|
|
unsigned Idx =
|
|
cast<ConstantInt>(AddrInst->getOperand(i))->getZExtValue();
|
|
ConstantOffset += SL->getElementOffset(Idx);
|
|
} else {
|
|
uint64_t TypeSize = TD->getTypeAllocSize(GTI.getIndexedType());
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(AddrInst->getOperand(i))) {
|
|
ConstantOffset += CI->getSExtValue()*TypeSize;
|
|
} else if (TypeSize) { // Scales of zero don't do anything.
|
|
// We only allow one variable index at the moment.
|
|
if (VariableOperand != -1)
|
|
return false;
|
|
|
|
// Remember the variable index.
|
|
VariableOperand = i;
|
|
VariableScale = TypeSize;
|
|
}
|
|
}
|
|
}
|
|
|
|
// A common case is for the GEP to only do a constant offset. In this case,
|
|
// just add it to the disp field and check validity.
|
|
if (VariableOperand == -1) {
|
|
AddrMode.BaseOffs += ConstantOffset;
|
|
if (ConstantOffset == 0 || TLI.isLegalAddressingMode(AddrMode, AccessTy)){
|
|
// Check to see if we can fold the base pointer in too.
|
|
if (MatchAddr(AddrInst->getOperand(0), Depth+1))
|
|
return true;
|
|
}
|
|
AddrMode.BaseOffs -= ConstantOffset;
|
|
return false;
|
|
}
|
|
|
|
// Save the valid addressing mode in case we can't match.
|
|
ExtAddrMode BackupAddrMode = AddrMode;
|
|
unsigned OldSize = AddrModeInsts.size();
|
|
|
|
// See if the scale and offset amount is valid for this target.
|
|
AddrMode.BaseOffs += ConstantOffset;
|
|
|
|
// Match the base operand of the GEP.
|
|
if (!MatchAddr(AddrInst->getOperand(0), Depth+1)) {
|
|
// If it couldn't be matched, just stuff the value in a register.
|
|
if (AddrMode.HasBaseReg) {
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
return false;
|
|
}
|
|
AddrMode.HasBaseReg = true;
|
|
AddrMode.BaseReg = AddrInst->getOperand(0);
|
|
}
|
|
|
|
// Match the remaining variable portion of the GEP.
|
|
if (!MatchScaledValue(AddrInst->getOperand(VariableOperand), VariableScale,
|
|
Depth)) {
|
|
// If it couldn't be matched, try stuffing the base into a register
|
|
// instead of matching it, and retrying the match of the scale.
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
if (AddrMode.HasBaseReg)
|
|
return false;
|
|
AddrMode.HasBaseReg = true;
|
|
AddrMode.BaseReg = AddrInst->getOperand(0);
|
|
AddrMode.BaseOffs += ConstantOffset;
|
|
if (!MatchScaledValue(AddrInst->getOperand(VariableOperand),
|
|
VariableScale, Depth)) {
|
|
// If even that didn't work, bail.
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
return false;
|
|
}
|
|
}
|
|
|
|
return true;
|
|
}
|
|
case Instruction::SExt:
|
|
case Instruction::ZExt: {
|
|
Instruction *Ext = dyn_cast<Instruction>(AddrInst);
|
|
if (!Ext)
|
|
return false;
|
|
|
|
// Try to move this ext out of the way of the addressing mode.
|
|
// Ask for a method for doing so.
|
|
TypePromotionHelper::Action TPH =
|
|
TypePromotionHelper::getAction(Ext, InsertedTruncs, TLI, PromotedInsts);
|
|
if (!TPH)
|
|
return false;
|
|
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
unsigned CreatedInsts = 0;
|
|
Value *PromotedOperand =
|
|
TPH(Ext, TPT, PromotedInsts, CreatedInsts, nullptr, nullptr);
|
|
// SExt has been moved away.
|
|
// Thus either it will be rematched later in the recursive calls or it is
|
|
// gone. Anyway, we must not fold it into the addressing mode at this point.
|
|
// E.g.,
|
|
// op = add opnd, 1
|
|
// idx = ext op
|
|
// addr = gep base, idx
|
|
// is now:
|
|
// promotedOpnd = ext opnd <- no match here
|
|
// op = promoted_add promotedOpnd, 1 <- match (later in recursive calls)
|
|
// addr = gep base, op <- match
|
|
if (MovedAway)
|
|
*MovedAway = true;
|
|
|
|
assert(PromotedOperand &&
|
|
"TypePromotionHelper should have filtered out those cases");
|
|
|
|
ExtAddrMode BackupAddrMode = AddrMode;
|
|
unsigned OldSize = AddrModeInsts.size();
|
|
|
|
if (!MatchAddr(PromotedOperand, Depth) ||
|
|
!IsPromotionProfitable(AddrModeInsts.size(), OldSize + CreatedInsts,
|
|
PromotedOperand)) {
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
DEBUG(dbgs() << "Sign extension does not pay off: rollback\n");
|
|
TPT.rollback(LastKnownGood);
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
/// MatchAddr - If we can, try to add the value of 'Addr' into the current
|
|
/// addressing mode. If Addr can't be added to AddrMode this returns false and
|
|
/// leaves AddrMode unmodified. This assumes that Addr is either a pointer type
|
|
/// or intptr_t for the target.
|
|
///
|
|
bool AddressingModeMatcher::MatchAddr(Value *Addr, unsigned Depth) {
|
|
// Start a transaction at this point that we will rollback if the matching
|
|
// fails.
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
if (ConstantInt *CI = dyn_cast<ConstantInt>(Addr)) {
|
|
// Fold in immediates if legal for the target.
|
|
AddrMode.BaseOffs += CI->getSExtValue();
|
|
if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
|
|
return true;
|
|
AddrMode.BaseOffs -= CI->getSExtValue();
|
|
} else if (GlobalValue *GV = dyn_cast<GlobalValue>(Addr)) {
|
|
// If this is a global variable, try to fold it into the addressing mode.
|
|
if (!AddrMode.BaseGV) {
|
|
AddrMode.BaseGV = GV;
|
|
if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
|
|
return true;
|
|
AddrMode.BaseGV = nullptr;
|
|
}
|
|
} else if (Instruction *I = dyn_cast<Instruction>(Addr)) {
|
|
ExtAddrMode BackupAddrMode = AddrMode;
|
|
unsigned OldSize = AddrModeInsts.size();
|
|
|
|
// Check to see if it is possible to fold this operation.
|
|
bool MovedAway = false;
|
|
if (MatchOperationAddr(I, I->getOpcode(), Depth, &MovedAway)) {
|
|
// This instruction may have been move away. If so, there is nothing
|
|
// to check here.
|
|
if (MovedAway)
|
|
return true;
|
|
// Okay, it's possible to fold this. Check to see if it is actually
|
|
// *profitable* to do so. We use a simple cost model to avoid increasing
|
|
// register pressure too much.
|
|
if (I->hasOneUse() ||
|
|
IsProfitableToFoldIntoAddressingMode(I, BackupAddrMode, AddrMode)) {
|
|
AddrModeInsts.push_back(I);
|
|
return true;
|
|
}
|
|
|
|
// It isn't profitable to do this, roll back.
|
|
//cerr << "NOT FOLDING: " << *I;
|
|
AddrMode = BackupAddrMode;
|
|
AddrModeInsts.resize(OldSize);
|
|
TPT.rollback(LastKnownGood);
|
|
}
|
|
} else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Addr)) {
|
|
if (MatchOperationAddr(CE, CE->getOpcode(), Depth))
|
|
return true;
|
|
TPT.rollback(LastKnownGood);
|
|
} else if (isa<ConstantPointerNull>(Addr)) {
|
|
// Null pointer gets folded without affecting the addressing mode.
|
|
return true;
|
|
}
|
|
|
|
// Worse case, the target should support [reg] addressing modes. :)
|
|
if (!AddrMode.HasBaseReg) {
|
|
AddrMode.HasBaseReg = true;
|
|
AddrMode.BaseReg = Addr;
|
|
// Still check for legality in case the target supports [imm] but not [i+r].
|
|
if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
|
|
return true;
|
|
AddrMode.HasBaseReg = false;
|
|
AddrMode.BaseReg = nullptr;
|
|
}
|
|
|
|
// If the base register is already taken, see if we can do [r+r].
|
|
if (AddrMode.Scale == 0) {
|
|
AddrMode.Scale = 1;
|
|
AddrMode.ScaledReg = Addr;
|
|
if (TLI.isLegalAddressingMode(AddrMode, AccessTy))
|
|
return true;
|
|
AddrMode.Scale = 0;
|
|
AddrMode.ScaledReg = nullptr;
|
|
}
|
|
// Couldn't match.
|
|
TPT.rollback(LastKnownGood);
|
|
return false;
|
|
}
|
|
|
|
/// IsOperandAMemoryOperand - Check to see if all uses of OpVal by the specified
|
|
/// inline asm call are due to memory operands. If so, return true, otherwise
|
|
/// return false.
|
|
static bool IsOperandAMemoryOperand(CallInst *CI, InlineAsm *IA, Value *OpVal,
|
|
const TargetMachine &TM) {
|
|
const Function *F = CI->getParent()->getParent();
|
|
const TargetLowering *TLI = TM.getSubtargetImpl(*F)->getTargetLowering();
|
|
const TargetRegisterInfo *TRI = TM.getSubtargetImpl(*F)->getRegisterInfo();
|
|
TargetLowering::AsmOperandInfoVector TargetConstraints =
|
|
TLI->ParseConstraints(TRI, ImmutableCallSite(CI));
|
|
for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
|
|
TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
|
|
|
|
// Compute the constraint code and ConstraintType to use.
|
|
TLI->ComputeConstraintToUse(OpInfo, SDValue());
|
|
|
|
// If this asm operand is our Value*, and if it isn't an indirect memory
|
|
// operand, we can't fold it!
|
|
if (OpInfo.CallOperandVal == OpVal &&
|
|
(OpInfo.ConstraintType != TargetLowering::C_Memory ||
|
|
!OpInfo.isIndirect))
|
|
return false;
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/// FindAllMemoryUses - Recursively walk all the uses of I until we find a
|
|
/// memory use. If we find an obviously non-foldable instruction, return true.
|
|
/// Add the ultimately found memory instructions to MemoryUses.
|
|
static bool FindAllMemoryUses(
|
|
Instruction *I,
|
|
SmallVectorImpl<std::pair<Instruction *, unsigned>> &MemoryUses,
|
|
SmallPtrSetImpl<Instruction *> &ConsideredInsts, const TargetMachine &TM) {
|
|
// If we already considered this instruction, we're done.
|
|
if (!ConsideredInsts.insert(I).second)
|
|
return false;
|
|
|
|
// If this is an obviously unfoldable instruction, bail out.
|
|
if (!MightBeFoldableInst(I))
|
|
return true;
|
|
|
|
// Loop over all the uses, recursively processing them.
|
|
for (Use &U : I->uses()) {
|
|
Instruction *UserI = cast<Instruction>(U.getUser());
|
|
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(UserI)) {
|
|
MemoryUses.push_back(std::make_pair(LI, U.getOperandNo()));
|
|
continue;
|
|
}
|
|
|
|
if (StoreInst *SI = dyn_cast<StoreInst>(UserI)) {
|
|
unsigned opNo = U.getOperandNo();
|
|
if (opNo == 0) return true; // Storing addr, not into addr.
|
|
MemoryUses.push_back(std::make_pair(SI, opNo));
|
|
continue;
|
|
}
|
|
|
|
if (CallInst *CI = dyn_cast<CallInst>(UserI)) {
|
|
InlineAsm *IA = dyn_cast<InlineAsm>(CI->getCalledValue());
|
|
if (!IA) return true;
|
|
|
|
// If this is a memory operand, we're cool, otherwise bail out.
|
|
if (!IsOperandAMemoryOperand(CI, IA, I, TM))
|
|
return true;
|
|
continue;
|
|
}
|
|
|
|
if (FindAllMemoryUses(UserI, MemoryUses, ConsideredInsts, TM))
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/// ValueAlreadyLiveAtInst - Retrn true if Val is already known to be live at
|
|
/// the use site that we're folding it into. If so, there is no cost to
|
|
/// include it in the addressing mode. KnownLive1 and KnownLive2 are two values
|
|
/// that we know are live at the instruction already.
|
|
bool AddressingModeMatcher::ValueAlreadyLiveAtInst(Value *Val,Value *KnownLive1,
|
|
Value *KnownLive2) {
|
|
// If Val is either of the known-live values, we know it is live!
|
|
if (Val == nullptr || Val == KnownLive1 || Val == KnownLive2)
|
|
return true;
|
|
|
|
// All values other than instructions and arguments (e.g. constants) are live.
|
|
if (!isa<Instruction>(Val) && !isa<Argument>(Val)) return true;
|
|
|
|
// If Val is a constant sized alloca in the entry block, it is live, this is
|
|
// true because it is just a reference to the stack/frame pointer, which is
|
|
// live for the whole function.
|
|
if (AllocaInst *AI = dyn_cast<AllocaInst>(Val))
|
|
if (AI->isStaticAlloca())
|
|
return true;
|
|
|
|
// Check to see if this value is already used in the memory instruction's
|
|
// block. If so, it's already live into the block at the very least, so we
|
|
// can reasonably fold it.
|
|
return Val->isUsedInBasicBlock(MemoryInst->getParent());
|
|
}
|
|
|
|
/// IsProfitableToFoldIntoAddressingMode - It is possible for the addressing
|
|
/// mode of the machine to fold the specified instruction into a load or store
|
|
/// that ultimately uses it. However, the specified instruction has multiple
|
|
/// uses. Given this, it may actually increase register pressure to fold it
|
|
/// into the load. For example, consider this code:
|
|
///
|
|
/// X = ...
|
|
/// Y = X+1
|
|
/// use(Y) -> nonload/store
|
|
/// Z = Y+1
|
|
/// load Z
|
|
///
|
|
/// In this case, Y has multiple uses, and can be folded into the load of Z
|
|
/// (yielding load [X+2]). However, doing this will cause both "X" and "X+1" to
|
|
/// be live at the use(Y) line. If we don't fold Y into load Z, we use one
|
|
/// fewer register. Since Y can't be folded into "use(Y)" we don't increase the
|
|
/// number of computations either.
|
|
///
|
|
/// Note that this (like most of CodeGenPrepare) is just a rough heuristic. If
|
|
/// X was live across 'load Z' for other reasons, we actually *would* want to
|
|
/// fold the addressing mode in the Z case. This would make Y die earlier.
|
|
bool AddressingModeMatcher::
|
|
IsProfitableToFoldIntoAddressingMode(Instruction *I, ExtAddrMode &AMBefore,
|
|
ExtAddrMode &AMAfter) {
|
|
if (IgnoreProfitability) return true;
|
|
|
|
// AMBefore is the addressing mode before this instruction was folded into it,
|
|
// and AMAfter is the addressing mode after the instruction was folded. Get
|
|
// the set of registers referenced by AMAfter and subtract out those
|
|
// referenced by AMBefore: this is the set of values which folding in this
|
|
// address extends the lifetime of.
|
|
//
|
|
// Note that there are only two potential values being referenced here,
|
|
// BaseReg and ScaleReg (global addresses are always available, as are any
|
|
// folded immediates).
|
|
Value *BaseReg = AMAfter.BaseReg, *ScaledReg = AMAfter.ScaledReg;
|
|
|
|
// If the BaseReg or ScaledReg was referenced by the previous addrmode, their
|
|
// lifetime wasn't extended by adding this instruction.
|
|
if (ValueAlreadyLiveAtInst(BaseReg, AMBefore.BaseReg, AMBefore.ScaledReg))
|
|
BaseReg = nullptr;
|
|
if (ValueAlreadyLiveAtInst(ScaledReg, AMBefore.BaseReg, AMBefore.ScaledReg))
|
|
ScaledReg = nullptr;
|
|
|
|
// If folding this instruction (and it's subexprs) didn't extend any live
|
|
// ranges, we're ok with it.
|
|
if (!BaseReg && !ScaledReg)
|
|
return true;
|
|
|
|
// If all uses of this instruction are ultimately load/store/inlineasm's,
|
|
// check to see if their addressing modes will include this instruction. If
|
|
// so, we can fold it into all uses, so it doesn't matter if it has multiple
|
|
// uses.
|
|
SmallVector<std::pair<Instruction*,unsigned>, 16> MemoryUses;
|
|
SmallPtrSet<Instruction*, 16> ConsideredInsts;
|
|
if (FindAllMemoryUses(I, MemoryUses, ConsideredInsts, TM))
|
|
return false; // Has a non-memory, non-foldable use!
|
|
|
|
// Now that we know that all uses of this instruction are part of a chain of
|
|
// computation involving only operations that could theoretically be folded
|
|
// into a memory use, loop over each of these uses and see if they could
|
|
// *actually* fold the instruction.
|
|
SmallVector<Instruction*, 32> MatchedAddrModeInsts;
|
|
for (unsigned i = 0, e = MemoryUses.size(); i != e; ++i) {
|
|
Instruction *User = MemoryUses[i].first;
|
|
unsigned OpNo = MemoryUses[i].second;
|
|
|
|
// Get the access type of this use. If the use isn't a pointer, we don't
|
|
// know what it accesses.
|
|
Value *Address = User->getOperand(OpNo);
|
|
if (!Address->getType()->isPointerTy())
|
|
return false;
|
|
Type *AddressAccessTy = Address->getType()->getPointerElementType();
|
|
|
|
// Do a match against the root of this address, ignoring profitability. This
|
|
// will tell us if the addressing mode for the memory operation will
|
|
// *actually* cover the shared instruction.
|
|
ExtAddrMode Result;
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
AddressingModeMatcher Matcher(MatchedAddrModeInsts, TM, AddressAccessTy,
|
|
MemoryInst, Result, InsertedTruncs,
|
|
PromotedInsts, TPT);
|
|
Matcher.IgnoreProfitability = true;
|
|
bool Success = Matcher.MatchAddr(Address, 0);
|
|
(void)Success; assert(Success && "Couldn't select *anything*?");
|
|
|
|
// The match was to check the profitability, the changes made are not
|
|
// part of the original matcher. Therefore, they should be dropped
|
|
// otherwise the original matcher will not present the right state.
|
|
TPT.rollback(LastKnownGood);
|
|
|
|
// If the match didn't cover I, then it won't be shared by it.
|
|
if (std::find(MatchedAddrModeInsts.begin(), MatchedAddrModeInsts.end(),
|
|
I) == MatchedAddrModeInsts.end())
|
|
return false;
|
|
|
|
MatchedAddrModeInsts.clear();
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
} // end anonymous namespace
|
|
|
|
/// IsNonLocalValue - Return true if the specified values are defined in a
|
|
/// different basic block than BB.
|
|
static bool IsNonLocalValue(Value *V, BasicBlock *BB) {
|
|
if (Instruction *I = dyn_cast<Instruction>(V))
|
|
return I->getParent() != BB;
|
|
return false;
|
|
}
|
|
|
|
/// OptimizeMemoryInst - Load and Store Instructions often have
|
|
/// addressing modes that can do significant amounts of computation. As such,
|
|
/// instruction selection will try to get the load or store to do as much
|
|
/// computation as possible for the program. The problem is that isel can only
|
|
/// see within a single block. As such, we sink as much legal addressing mode
|
|
/// stuff into the block as possible.
|
|
///
|
|
/// This method is used to optimize both load/store and inline asms with memory
|
|
/// operands.
|
|
bool CodeGenPrepare::OptimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
|
|
Type *AccessTy) {
|
|
Value *Repl = Addr;
|
|
|
|
// Try to collapse single-value PHI nodes. This is necessary to undo
|
|
// unprofitable PRE transformations.
|
|
SmallVector<Value*, 8> worklist;
|
|
SmallPtrSet<Value*, 16> Visited;
|
|
worklist.push_back(Addr);
|
|
|
|
// Use a worklist to iteratively look through PHI nodes, and ensure that
|
|
// the addressing mode obtained from the non-PHI roots of the graph
|
|
// are equivalent.
|
|
Value *Consensus = nullptr;
|
|
unsigned NumUsesConsensus = 0;
|
|
bool IsNumUsesConsensusValid = false;
|
|
SmallVector<Instruction*, 16> AddrModeInsts;
|
|
ExtAddrMode AddrMode;
|
|
TypePromotionTransaction TPT;
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
while (!worklist.empty()) {
|
|
Value *V = worklist.back();
|
|
worklist.pop_back();
|
|
|
|
// Break use-def graph loops.
|
|
if (!Visited.insert(V).second) {
|
|
Consensus = nullptr;
|
|
break;
|
|
}
|
|
|
|
// For a PHI node, push all of its incoming values.
|
|
if (PHINode *P = dyn_cast<PHINode>(V)) {
|
|
for (unsigned i = 0, e = P->getNumIncomingValues(); i != e; ++i)
|
|
worklist.push_back(P->getIncomingValue(i));
|
|
continue;
|
|
}
|
|
|
|
// For non-PHIs, determine the addressing mode being computed.
|
|
SmallVector<Instruction*, 16> NewAddrModeInsts;
|
|
ExtAddrMode NewAddrMode = AddressingModeMatcher::Match(
|
|
V, AccessTy, MemoryInst, NewAddrModeInsts, *TM, InsertedTruncsSet,
|
|
PromotedInsts, TPT);
|
|
|
|
// This check is broken into two cases with very similar code to avoid using
|
|
// getNumUses() as much as possible. Some values have a lot of uses, so
|
|
// calling getNumUses() unconditionally caused a significant compile-time
|
|
// regression.
|
|
if (!Consensus) {
|
|
Consensus = V;
|
|
AddrMode = NewAddrMode;
|
|
AddrModeInsts = NewAddrModeInsts;
|
|
continue;
|
|
} else if (NewAddrMode == AddrMode) {
|
|
if (!IsNumUsesConsensusValid) {
|
|
NumUsesConsensus = Consensus->getNumUses();
|
|
IsNumUsesConsensusValid = true;
|
|
}
|
|
|
|
// Ensure that the obtained addressing mode is equivalent to that obtained
|
|
// for all other roots of the PHI traversal. Also, when choosing one
|
|
// such root as representative, select the one with the most uses in order
|
|
// to keep the cost modeling heuristics in AddressingModeMatcher
|
|
// applicable.
|
|
unsigned NumUses = V->getNumUses();
|
|
if (NumUses > NumUsesConsensus) {
|
|
Consensus = V;
|
|
NumUsesConsensus = NumUses;
|
|
AddrModeInsts = NewAddrModeInsts;
|
|
}
|
|
continue;
|
|
}
|
|
|
|
Consensus = nullptr;
|
|
break;
|
|
}
|
|
|
|
// If the addressing mode couldn't be determined, or if multiple different
|
|
// ones were determined, bail out now.
|
|
if (!Consensus) {
|
|
TPT.rollback(LastKnownGood);
|
|
return false;
|
|
}
|
|
TPT.commit();
|
|
|
|
// Check to see if any of the instructions supersumed by this addr mode are
|
|
// non-local to I's BB.
|
|
bool AnyNonLocal = false;
|
|
for (unsigned i = 0, e = AddrModeInsts.size(); i != e; ++i) {
|
|
if (IsNonLocalValue(AddrModeInsts[i], MemoryInst->getParent())) {
|
|
AnyNonLocal = true;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// If all the instructions matched are already in this BB, don't do anything.
|
|
if (!AnyNonLocal) {
|
|
DEBUG(dbgs() << "CGP: Found local addrmode: " << AddrMode << "\n");
|
|
return false;
|
|
}
|
|
|
|
// Insert this computation right after this user. Since our caller is
|
|
// scanning from the top of the BB to the bottom, reuse of the expr are
|
|
// guaranteed to happen later.
|
|
IRBuilder<> Builder(MemoryInst);
|
|
|
|
// Now that we determined the addressing expression we want to use and know
|
|
// that we have to sink it into this block. Check to see if we have already
|
|
// done this for some other load/store instr in this block. If so, reuse the
|
|
// computation.
|
|
Value *&SunkAddr = SunkAddrs[Addr];
|
|
if (SunkAddr) {
|
|
DEBUG(dbgs() << "CGP: Reusing nonlocal addrmode: " << AddrMode << " for "
|
|
<< *MemoryInst << "\n");
|
|
if (SunkAddr->getType() != Addr->getType())
|
|
SunkAddr = Builder.CreateBitCast(SunkAddr, Addr->getType());
|
|
} else if (AddrSinkUsingGEPs ||
|
|
(!AddrSinkUsingGEPs.getNumOccurrences() && TM &&
|
|
TM->getSubtargetImpl(*MemoryInst->getParent()->getParent())
|
|
->useAA())) {
|
|
// By default, we use the GEP-based method when AA is used later. This
|
|
// prevents new inttoptr/ptrtoint pairs from degrading AA capabilities.
|
|
DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "
|
|
<< *MemoryInst << "\n");
|
|
Type *IntPtrTy = TLI->getDataLayout()->getIntPtrType(Addr->getType());
|
|
Value *ResultPtr = nullptr, *ResultIndex = nullptr;
|
|
|
|
// First, find the pointer.
|
|
if (AddrMode.BaseReg && AddrMode.BaseReg->getType()->isPointerTy()) {
|
|
ResultPtr = AddrMode.BaseReg;
|
|
AddrMode.BaseReg = nullptr;
|
|
}
|
|
|
|
if (AddrMode.Scale && AddrMode.ScaledReg->getType()->isPointerTy()) {
|
|
// We can't add more than one pointer together, nor can we scale a
|
|
// pointer (both of which seem meaningless).
|
|
if (ResultPtr || AddrMode.Scale != 1)
|
|
return false;
|
|
|
|
ResultPtr = AddrMode.ScaledReg;
|
|
AddrMode.Scale = 0;
|
|
}
|
|
|
|
if (AddrMode.BaseGV) {
|
|
if (ResultPtr)
|
|
return false;
|
|
|
|
ResultPtr = AddrMode.BaseGV;
|
|
}
|
|
|
|
// If the real base value actually came from an inttoptr, then the matcher
|
|
// will look through it and provide only the integer value. In that case,
|
|
// use it here.
|
|
if (!ResultPtr && AddrMode.BaseReg) {
|
|
ResultPtr =
|
|
Builder.CreateIntToPtr(AddrMode.BaseReg, Addr->getType(), "sunkaddr");
|
|
AddrMode.BaseReg = nullptr;
|
|
} else if (!ResultPtr && AddrMode.Scale == 1) {
|
|
ResultPtr =
|
|
Builder.CreateIntToPtr(AddrMode.ScaledReg, Addr->getType(), "sunkaddr");
|
|
AddrMode.Scale = 0;
|
|
}
|
|
|
|
if (!ResultPtr &&
|
|
!AddrMode.BaseReg && !AddrMode.Scale && !AddrMode.BaseOffs) {
|
|
SunkAddr = Constant::getNullValue(Addr->getType());
|
|
} else if (!ResultPtr) {
|
|
return false;
|
|
} else {
|
|
Type *I8PtrTy =
|
|
Builder.getInt8PtrTy(Addr->getType()->getPointerAddressSpace());
|
|
|
|
// Start with the base register. Do this first so that subsequent address
|
|
// matching finds it last, which will prevent it from trying to match it
|
|
// as the scaled value in case it happens to be a mul. That would be
|
|
// problematic if we've sunk a different mul for the scale, because then
|
|
// we'd end up sinking both muls.
|
|
if (AddrMode.BaseReg) {
|
|
Value *V = AddrMode.BaseReg;
|
|
if (V->getType() != IntPtrTy)
|
|
V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
|
|
|
|
ResultIndex = V;
|
|
}
|
|
|
|
// Add the scale value.
|
|
if (AddrMode.Scale) {
|
|
Value *V = AddrMode.ScaledReg;
|
|
if (V->getType() == IntPtrTy) {
|
|
// done.
|
|
} else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
|
|
cast<IntegerType>(V->getType())->getBitWidth()) {
|
|
V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
|
|
} else {
|
|
// It is only safe to sign extend the BaseReg if we know that the math
|
|
// required to create it did not overflow before we extend it. Since
|
|
// the original IR value was tossed in favor of a constant back when
|
|
// the AddrMode was created we need to bail out gracefully if widths
|
|
// do not match instead of extending it.
|
|
Instruction *I = dyn_cast_or_null<Instruction>(ResultIndex);
|
|
if (I && (ResultIndex != AddrMode.BaseReg))
|
|
I->eraseFromParent();
|
|
return false;
|
|
}
|
|
|
|
if (AddrMode.Scale != 1)
|
|
V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
|
|
"sunkaddr");
|
|
if (ResultIndex)
|
|
ResultIndex = Builder.CreateAdd(ResultIndex, V, "sunkaddr");
|
|
else
|
|
ResultIndex = V;
|
|
}
|
|
|
|
// Add in the Base Offset if present.
|
|
if (AddrMode.BaseOffs) {
|
|
Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
|
|
if (ResultIndex) {
|
|
// We need to add this separately from the scale above to help with
|
|
// SDAG consecutive load/store merging.
|
|
if (ResultPtr->getType() != I8PtrTy)
|
|
ResultPtr = Builder.CreateBitCast(ResultPtr, I8PtrTy);
|
|
ResultPtr = Builder.CreateGEP(ResultPtr, ResultIndex, "sunkaddr");
|
|
}
|
|
|
|
ResultIndex = V;
|
|
}
|
|
|
|
if (!ResultIndex) {
|
|
SunkAddr = ResultPtr;
|
|
} else {
|
|
if (ResultPtr->getType() != I8PtrTy)
|
|
ResultPtr = Builder.CreateBitCast(ResultPtr, I8PtrTy);
|
|
SunkAddr = Builder.CreateGEP(ResultPtr, ResultIndex, "sunkaddr");
|
|
}
|
|
|
|
if (SunkAddr->getType() != Addr->getType())
|
|
SunkAddr = Builder.CreateBitCast(SunkAddr, Addr->getType());
|
|
}
|
|
} else {
|
|
DEBUG(dbgs() << "CGP: SINKING nonlocal addrmode: " << AddrMode << " for "
|
|
<< *MemoryInst << "\n");
|
|
Type *IntPtrTy = TLI->getDataLayout()->getIntPtrType(Addr->getType());
|
|
Value *Result = nullptr;
|
|
|
|
// Start with the base register. Do this first so that subsequent address
|
|
// matching finds it last, which will prevent it from trying to match it
|
|
// as the scaled value in case it happens to be a mul. That would be
|
|
// problematic if we've sunk a different mul for the scale, because then
|
|
// we'd end up sinking both muls.
|
|
if (AddrMode.BaseReg) {
|
|
Value *V = AddrMode.BaseReg;
|
|
if (V->getType()->isPointerTy())
|
|
V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
|
|
if (V->getType() != IntPtrTy)
|
|
V = Builder.CreateIntCast(V, IntPtrTy, /*isSigned=*/true, "sunkaddr");
|
|
Result = V;
|
|
}
|
|
|
|
// Add the scale value.
|
|
if (AddrMode.Scale) {
|
|
Value *V = AddrMode.ScaledReg;
|
|
if (V->getType() == IntPtrTy) {
|
|
// done.
|
|
} else if (V->getType()->isPointerTy()) {
|
|
V = Builder.CreatePtrToInt(V, IntPtrTy, "sunkaddr");
|
|
} else if (cast<IntegerType>(IntPtrTy)->getBitWidth() <
|
|
cast<IntegerType>(V->getType())->getBitWidth()) {
|
|
V = Builder.CreateTrunc(V, IntPtrTy, "sunkaddr");
|
|
} else {
|
|
// It is only safe to sign extend the BaseReg if we know that the math
|
|
// required to create it did not overflow before we extend it. Since
|
|
// the original IR value was tossed in favor of a constant back when
|
|
// the AddrMode was created we need to bail out gracefully if widths
|
|
// do not match instead of extending it.
|
|
Instruction *I = dyn_cast_or_null<Instruction>(Result);
|
|
if (I && (Result != AddrMode.BaseReg))
|
|
I->eraseFromParent();
|
|
return false;
|
|
}
|
|
if (AddrMode.Scale != 1)
|
|
V = Builder.CreateMul(V, ConstantInt::get(IntPtrTy, AddrMode.Scale),
|
|
"sunkaddr");
|
|
if (Result)
|
|
Result = Builder.CreateAdd(Result, V, "sunkaddr");
|
|
else
|
|
Result = V;
|
|
}
|
|
|
|
// Add in the BaseGV if present.
|
|
if (AddrMode.BaseGV) {
|
|
Value *V = Builder.CreatePtrToInt(AddrMode.BaseGV, IntPtrTy, "sunkaddr");
|
|
if (Result)
|
|
Result = Builder.CreateAdd(Result, V, "sunkaddr");
|
|
else
|
|
Result = V;
|
|
}
|
|
|
|
// Add in the Base Offset if present.
|
|
if (AddrMode.BaseOffs) {
|
|
Value *V = ConstantInt::get(IntPtrTy, AddrMode.BaseOffs);
|
|
if (Result)
|
|
Result = Builder.CreateAdd(Result, V, "sunkaddr");
|
|
else
|
|
Result = V;
|
|
}
|
|
|
|
if (!Result)
|
|
SunkAddr = Constant::getNullValue(Addr->getType());
|
|
else
|
|
SunkAddr = Builder.CreateIntToPtr(Result, Addr->getType(), "sunkaddr");
|
|
}
|
|
|
|
MemoryInst->replaceUsesOfWith(Repl, SunkAddr);
|
|
|
|
// If we have no uses, recursively delete the value and all dead instructions
|
|
// using it.
|
|
if (Repl->use_empty()) {
|
|
// This can cause recursive deletion, which can invalidate our iterator.
|
|
// Use a WeakVH to hold onto it in case this happens.
|
|
WeakVH IterHandle(CurInstIterator);
|
|
BasicBlock *BB = CurInstIterator->getParent();
|
|
|
|
RecursivelyDeleteTriviallyDeadInstructions(Repl, TLInfo);
|
|
|
|
if (IterHandle != CurInstIterator) {
|
|
// If the iterator instruction was recursively deleted, start over at the
|
|
// start of the block.
|
|
CurInstIterator = BB->begin();
|
|
SunkAddrs.clear();
|
|
}
|
|
}
|
|
++NumMemoryInsts;
|
|
return true;
|
|
}
|
|
|
|
/// OptimizeInlineAsmInst - If there are any memory operands, use
|
|
/// OptimizeMemoryInst to sink their address computing into the block when
|
|
/// possible / profitable.
|
|
bool CodeGenPrepare::OptimizeInlineAsmInst(CallInst *CS) {
|
|
bool MadeChange = false;
|
|
|
|
const TargetRegisterInfo *TRI =
|
|
TM->getSubtargetImpl(*CS->getParent()->getParent())->getRegisterInfo();
|
|
TargetLowering::AsmOperandInfoVector
|
|
TargetConstraints = TLI->ParseConstraints(TRI, CS);
|
|
unsigned ArgNo = 0;
|
|
for (unsigned i = 0, e = TargetConstraints.size(); i != e; ++i) {
|
|
TargetLowering::AsmOperandInfo &OpInfo = TargetConstraints[i];
|
|
|
|
// Compute the constraint code and ConstraintType to use.
|
|
TLI->ComputeConstraintToUse(OpInfo, SDValue());
|
|
|
|
if (OpInfo.ConstraintType == TargetLowering::C_Memory &&
|
|
OpInfo.isIndirect) {
|
|
Value *OpVal = CS->getArgOperand(ArgNo++);
|
|
MadeChange |= OptimizeMemoryInst(CS, OpVal, OpVal->getType());
|
|
} else if (OpInfo.Type == InlineAsm::isInput)
|
|
ArgNo++;
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
/// \brief Check if all the uses of \p Inst are equivalent (or free) zero or
|
|
/// sign extensions.
|
|
static bool hasSameExtUse(Instruction *Inst, const TargetLowering &TLI) {
|
|
assert(!Inst->use_empty() && "Input must have at least one use");
|
|
const Instruction *FirstUser = cast<Instruction>(*Inst->user_begin());
|
|
bool IsSExt = isa<SExtInst>(FirstUser);
|
|
Type *ExtTy = FirstUser->getType();
|
|
for (const User *U : Inst->users()) {
|
|
const Instruction *UI = cast<Instruction>(U);
|
|
if ((IsSExt && !isa<SExtInst>(UI)) || (!IsSExt && !isa<ZExtInst>(UI)))
|
|
return false;
|
|
Type *CurTy = UI->getType();
|
|
// Same input and output types: Same instruction after CSE.
|
|
if (CurTy == ExtTy)
|
|
continue;
|
|
|
|
// If IsSExt is true, we are in this situation:
|
|
// a = Inst
|
|
// b = sext ty1 a to ty2
|
|
// c = sext ty1 a to ty3
|
|
// Assuming ty2 is shorter than ty3, this could be turned into:
|
|
// a = Inst
|
|
// b = sext ty1 a to ty2
|
|
// c = sext ty2 b to ty3
|
|
// However, the last sext is not free.
|
|
if (IsSExt)
|
|
return false;
|
|
|
|
// This is a ZExt, maybe this is free to extend from one type to another.
|
|
// In that case, we would not account for a different use.
|
|
Type *NarrowTy;
|
|
Type *LargeTy;
|
|
if (ExtTy->getScalarType()->getIntegerBitWidth() >
|
|
CurTy->getScalarType()->getIntegerBitWidth()) {
|
|
NarrowTy = CurTy;
|
|
LargeTy = ExtTy;
|
|
} else {
|
|
NarrowTy = ExtTy;
|
|
LargeTy = CurTy;
|
|
}
|
|
|
|
if (!TLI.isZExtFree(NarrowTy, LargeTy))
|
|
return false;
|
|
}
|
|
// All uses are the same or can be derived from one another for free.
|
|
return true;
|
|
}
|
|
|
|
/// \brief Try to form ExtLd by promoting \p Exts until they reach a
|
|
/// load instruction.
|
|
/// If an ext(load) can be formed, it is returned via \p LI for the load
|
|
/// and \p Inst for the extension.
|
|
/// Otherwise LI == nullptr and Inst == nullptr.
|
|
/// When some promotion happened, \p TPT contains the proper state to
|
|
/// revert them.
|
|
///
|
|
/// \return true when promoting was necessary to expose the ext(load)
|
|
/// opportunity, false otherwise.
|
|
///
|
|
/// Example:
|
|
/// \code
|
|
/// %ld = load i32* %addr
|
|
/// %add = add nuw i32 %ld, 4
|
|
/// %zext = zext i32 %add to i64
|
|
/// \endcode
|
|
/// =>
|
|
/// \code
|
|
/// %ld = load i32* %addr
|
|
/// %zext = zext i32 %ld to i64
|
|
/// %add = add nuw i64 %zext, 4
|
|
/// \encode
|
|
/// Thanks to the promotion, we can match zext(load i32*) to i64.
|
|
bool CodeGenPrepare::ExtLdPromotion(TypePromotionTransaction &TPT,
|
|
LoadInst *&LI, Instruction *&Inst,
|
|
const SmallVectorImpl<Instruction *> &Exts,
|
|
unsigned CreatedInsts = 0) {
|
|
// Iterate over all the extensions to see if one form an ext(load).
|
|
for (auto I : Exts) {
|
|
// Check if we directly have ext(load).
|
|
if ((LI = dyn_cast<LoadInst>(I->getOperand(0)))) {
|
|
Inst = I;
|
|
// No promotion happened here.
|
|
return false;
|
|
}
|
|
// Check whether or not we want to do any promotion.
|
|
if (!TLI || !TLI->enableExtLdPromotion() || DisableExtLdPromotion)
|
|
continue;
|
|
// Get the action to perform the promotion.
|
|
TypePromotionHelper::Action TPH = TypePromotionHelper::getAction(
|
|
I, InsertedTruncsSet, *TLI, PromotedInsts);
|
|
// Check if we can promote.
|
|
if (!TPH)
|
|
continue;
|
|
// Save the current state.
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
SmallVector<Instruction *, 4> NewExts;
|
|
unsigned NewCreatedInsts = 0;
|
|
// Promote.
|
|
Value *PromotedVal =
|
|
TPH(I, TPT, PromotedInsts, NewCreatedInsts, &NewExts, nullptr);
|
|
assert(PromotedVal &&
|
|
"TypePromotionHelper should have filtered out those cases");
|
|
|
|
// We would be able to merge only one extension in a load.
|
|
// Therefore, if we have more than 1 new extension we heuristically
|
|
// cut this search path, because it means we degrade the code quality.
|
|
// With exactly 2, the transformation is neutral, because we will merge
|
|
// one extension but leave one. However, we optimistically keep going,
|
|
// because the new extension may be removed too.
|
|
unsigned TotalCreatedInsts = CreatedInsts + NewCreatedInsts;
|
|
if (!StressExtLdPromotion &&
|
|
(TotalCreatedInsts > 1 ||
|
|
!isPromotedInstructionLegal(*TLI, PromotedVal))) {
|
|
// The promotion is not profitable, rollback to the previous state.
|
|
TPT.rollback(LastKnownGood);
|
|
continue;
|
|
}
|
|
// The promotion is profitable.
|
|
// Check if it exposes an ext(load).
|
|
(void)ExtLdPromotion(TPT, LI, Inst, NewExts, TotalCreatedInsts);
|
|
if (LI && (StressExtLdPromotion || NewCreatedInsts == 0 ||
|
|
// If we have created a new extension, i.e., now we have two
|
|
// extensions. We must make sure one of them is merged with
|
|
// the load, otherwise we may degrade the code quality.
|
|
(LI->hasOneUse() || hasSameExtUse(LI, *TLI))))
|
|
// Promotion happened.
|
|
return true;
|
|
// If this does not help to expose an ext(load) then, rollback.
|
|
TPT.rollback(LastKnownGood);
|
|
}
|
|
// None of the extension can form an ext(load).
|
|
LI = nullptr;
|
|
Inst = nullptr;
|
|
return false;
|
|
}
|
|
|
|
/// MoveExtToFormExtLoad - Move a zext or sext fed by a load into the same
|
|
/// basic block as the load, unless conditions are unfavorable. This allows
|
|
/// SelectionDAG to fold the extend into the load.
|
|
/// \p I[in/out] the extension may be modified during the process if some
|
|
/// promotions apply.
|
|
///
|
|
bool CodeGenPrepare::MoveExtToFormExtLoad(Instruction *&I) {
|
|
// Try to promote a chain of computation if it allows to form
|
|
// an extended load.
|
|
TypePromotionTransaction TPT;
|
|
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
|
|
TPT.getRestorationPoint();
|
|
SmallVector<Instruction *, 1> Exts;
|
|
Exts.push_back(I);
|
|
// Look for a load being extended.
|
|
LoadInst *LI = nullptr;
|
|
Instruction *OldExt = I;
|
|
bool HasPromoted = ExtLdPromotion(TPT, LI, I, Exts);
|
|
if (!LI || !I) {
|
|
assert(!HasPromoted && !LI && "If we did not match any load instruction "
|
|
"the code must remain the same");
|
|
I = OldExt;
|
|
return false;
|
|
}
|
|
|
|
// If they're already in the same block, there's nothing to do.
|
|
// Make the cheap checks first if we did not promote.
|
|
// If we promoted, we need to check if it is indeed profitable.
|
|
if (!HasPromoted && LI->getParent() == I->getParent())
|
|
return false;
|
|
|
|
EVT VT = TLI->getValueType(I->getType());
|
|
EVT LoadVT = TLI->getValueType(LI->getType());
|
|
|
|
// If the load has other users and the truncate is not free, this probably
|
|
// isn't worthwhile.
|
|
if (!LI->hasOneUse() && TLI &&
|
|
(TLI->isTypeLegal(LoadVT) || !TLI->isTypeLegal(VT)) &&
|
|
!TLI->isTruncateFree(I->getType(), LI->getType())) {
|
|
I = OldExt;
|
|
TPT.rollback(LastKnownGood);
|
|
return false;
|
|
}
|
|
|
|
// Check whether the target supports casts folded into loads.
|
|
unsigned LType;
|
|
if (isa<ZExtInst>(I))
|
|
LType = ISD::ZEXTLOAD;
|
|
else {
|
|
assert(isa<SExtInst>(I) && "Unexpected ext type!");
|
|
LType = ISD::SEXTLOAD;
|
|
}
|
|
if (TLI && !TLI->isLoadExtLegal(LType, VT, LoadVT)) {
|
|
I = OldExt;
|
|
TPT.rollback(LastKnownGood);
|
|
return false;
|
|
}
|
|
|
|
// Move the extend into the same block as the load, so that SelectionDAG
|
|
// can fold it.
|
|
TPT.commit();
|
|
I->removeFromParent();
|
|
I->insertAfter(LI);
|
|
++NumExtsMoved;
|
|
return true;
|
|
}
|
|
|
|
bool CodeGenPrepare::OptimizeExtUses(Instruction *I) {
|
|
BasicBlock *DefBB = I->getParent();
|
|
|
|
// If the result of a {s|z}ext and its source are both live out, rewrite all
|
|
// other uses of the source with result of extension.
|
|
Value *Src = I->getOperand(0);
|
|
if (Src->hasOneUse())
|
|
return false;
|
|
|
|
// Only do this xform if truncating is free.
|
|
if (TLI && !TLI->isTruncateFree(I->getType(), Src->getType()))
|
|
return false;
|
|
|
|
// Only safe to perform the optimization if the source is also defined in
|
|
// this block.
|
|
if (!isa<Instruction>(Src) || DefBB != cast<Instruction>(Src)->getParent())
|
|
return false;
|
|
|
|
bool DefIsLiveOut = false;
|
|
for (User *U : I->users()) {
|
|
Instruction *UI = cast<Instruction>(U);
|
|
|
|
// Figure out which BB this ext is used in.
|
|
BasicBlock *UserBB = UI->getParent();
|
|
if (UserBB == DefBB) continue;
|
|
DefIsLiveOut = true;
|
|
break;
|
|
}
|
|
if (!DefIsLiveOut)
|
|
return false;
|
|
|
|
// Make sure none of the uses are PHI nodes.
|
|
for (User *U : Src->users()) {
|
|
Instruction *UI = cast<Instruction>(U);
|
|
BasicBlock *UserBB = UI->getParent();
|
|
if (UserBB == DefBB) continue;
|
|
// Be conservative. We don't want this xform to end up introducing
|
|
// reloads just before load / store instructions.
|
|
if (isa<PHINode>(UI) || isa<LoadInst>(UI) || isa<StoreInst>(UI))
|
|
return false;
|
|
}
|
|
|
|
// InsertedTruncs - Only insert one trunc in each block once.
|
|
DenseMap<BasicBlock*, Instruction*> InsertedTruncs;
|
|
|
|
bool MadeChange = false;
|
|
for (Use &U : Src->uses()) {
|
|
Instruction *User = cast<Instruction>(U.getUser());
|
|
|
|
// Figure out which BB this ext is used in.
|
|
BasicBlock *UserBB = User->getParent();
|
|
if (UserBB == DefBB) continue;
|
|
|
|
// Both src and def are live in this block. Rewrite the use.
|
|
Instruction *&InsertedTrunc = InsertedTruncs[UserBB];
|
|
|
|
if (!InsertedTrunc) {
|
|
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
|
|
InsertedTrunc = new TruncInst(I, Src->getType(), "", InsertPt);
|
|
InsertedTruncsSet.insert(InsertedTrunc);
|
|
}
|
|
|
|
// Replace a use of the {s|z}ext source with a use of the result.
|
|
U = InsertedTrunc;
|
|
++NumExtUses;
|
|
MadeChange = true;
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
/// isFormingBranchFromSelectProfitable - Returns true if a SelectInst should be
|
|
/// turned into an explicit branch.
|
|
static bool isFormingBranchFromSelectProfitable(SelectInst *SI) {
|
|
// FIXME: This should use the same heuristics as IfConversion to determine
|
|
// whether a select is better represented as a branch. This requires that
|
|
// branch probability metadata is preserved for the select, which is not the
|
|
// case currently.
|
|
|
|
CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
|
|
|
|
// If the branch is predicted right, an out of order CPU can avoid blocking on
|
|
// the compare. Emit cmovs on compares with a memory operand as branches to
|
|
// avoid stalls on the load from memory. If the compare has more than one use
|
|
// there's probably another cmov or setcc around so it's not worth emitting a
|
|
// branch.
|
|
if (!Cmp)
|
|
return false;
|
|
|
|
Value *CmpOp0 = Cmp->getOperand(0);
|
|
Value *CmpOp1 = Cmp->getOperand(1);
|
|
|
|
// We check that the memory operand has one use to avoid uses of the loaded
|
|
// value directly after the compare, making branches unprofitable.
|
|
return Cmp->hasOneUse() &&
|
|
((isa<LoadInst>(CmpOp0) && CmpOp0->hasOneUse()) ||
|
|
(isa<LoadInst>(CmpOp1) && CmpOp1->hasOneUse()));
|
|
}
|
|
|
|
|
|
/// If we have a SelectInst that will likely profit from branch prediction,
|
|
/// turn it into a branch.
|
|
bool CodeGenPrepare::OptimizeSelectInst(SelectInst *SI) {
|
|
bool VectorCond = !SI->getCondition()->getType()->isIntegerTy(1);
|
|
|
|
// Can we convert the 'select' to CF ?
|
|
if (DisableSelectToBranch || OptSize || !TLI || VectorCond)
|
|
return false;
|
|
|
|
TargetLowering::SelectSupportKind SelectKind;
|
|
if (VectorCond)
|
|
SelectKind = TargetLowering::VectorMaskSelect;
|
|
else if (SI->getType()->isVectorTy())
|
|
SelectKind = TargetLowering::ScalarCondVectorVal;
|
|
else
|
|
SelectKind = TargetLowering::ScalarValSelect;
|
|
|
|
// Do we have efficient codegen support for this kind of 'selects' ?
|
|
if (TLI->isSelectSupported(SelectKind)) {
|
|
// We have efficient codegen support for the select instruction.
|
|
// Check if it is profitable to keep this 'select'.
|
|
if (!TLI->isPredictableSelectExpensive() ||
|
|
!isFormingBranchFromSelectProfitable(SI))
|
|
return false;
|
|
}
|
|
|
|
ModifiedDT = true;
|
|
|
|
// First, we split the block containing the select into 2 blocks.
|
|
BasicBlock *StartBlock = SI->getParent();
|
|
BasicBlock::iterator SplitPt = ++(BasicBlock::iterator(SI));
|
|
BasicBlock *NextBlock = StartBlock->splitBasicBlock(SplitPt, "select.end");
|
|
|
|
// Create a new block serving as the landing pad for the branch.
|
|
BasicBlock *SmallBlock = BasicBlock::Create(SI->getContext(), "select.mid",
|
|
NextBlock->getParent(), NextBlock);
|
|
|
|
// Move the unconditional branch from the block with the select in it into our
|
|
// landing pad block.
|
|
StartBlock->getTerminator()->eraseFromParent();
|
|
BranchInst::Create(NextBlock, SmallBlock);
|
|
|
|
// Insert the real conditional branch based on the original condition.
|
|
BranchInst::Create(NextBlock, SmallBlock, SI->getCondition(), SI);
|
|
|
|
// The select itself is replaced with a PHI Node.
|
|
PHINode *PN = PHINode::Create(SI->getType(), 2, "", NextBlock->begin());
|
|
PN->takeName(SI);
|
|
PN->addIncoming(SI->getTrueValue(), StartBlock);
|
|
PN->addIncoming(SI->getFalseValue(), SmallBlock);
|
|
SI->replaceAllUsesWith(PN);
|
|
SI->eraseFromParent();
|
|
|
|
// Instruct OptimizeBlock to skip to the next block.
|
|
CurInstIterator = StartBlock->end();
|
|
++NumSelectsExpanded;
|
|
return true;
|
|
}
|
|
|
|
static bool isBroadcastShuffle(ShuffleVectorInst *SVI) {
|
|
SmallVector<int, 16> Mask(SVI->getShuffleMask());
|
|
int SplatElem = -1;
|
|
for (unsigned i = 0; i < Mask.size(); ++i) {
|
|
if (SplatElem != -1 && Mask[i] != -1 && Mask[i] != SplatElem)
|
|
return false;
|
|
SplatElem = Mask[i];
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/// Some targets have expensive vector shifts if the lanes aren't all the same
|
|
/// (e.g. x86 only introduced "vpsllvd" and friends with AVX2). In these cases
|
|
/// it's often worth sinking a shufflevector splat down to its use so that
|
|
/// codegen can spot all lanes are identical.
|
|
bool CodeGenPrepare::OptimizeShuffleVectorInst(ShuffleVectorInst *SVI) {
|
|
BasicBlock *DefBB = SVI->getParent();
|
|
|
|
// Only do this xform if variable vector shifts are particularly expensive.
|
|
if (!TLI || !TLI->isVectorShiftByScalarCheap(SVI->getType()))
|
|
return false;
|
|
|
|
// We only expect better codegen by sinking a shuffle if we can recognise a
|
|
// constant splat.
|
|
if (!isBroadcastShuffle(SVI))
|
|
return false;
|
|
|
|
// InsertedShuffles - Only insert a shuffle in each block once.
|
|
DenseMap<BasicBlock*, Instruction*> InsertedShuffles;
|
|
|
|
bool MadeChange = false;
|
|
for (User *U : SVI->users()) {
|
|
Instruction *UI = cast<Instruction>(U);
|
|
|
|
// Figure out which BB this ext is used in.
|
|
BasicBlock *UserBB = UI->getParent();
|
|
if (UserBB == DefBB) continue;
|
|
|
|
// For now only apply this when the splat is used by a shift instruction.
|
|
if (!UI->isShift()) continue;
|
|
|
|
// Everything checks out, sink the shuffle if the user's block doesn't
|
|
// already have a copy.
|
|
Instruction *&InsertedShuffle = InsertedShuffles[UserBB];
|
|
|
|
if (!InsertedShuffle) {
|
|
BasicBlock::iterator InsertPt = UserBB->getFirstInsertionPt();
|
|
InsertedShuffle = new ShuffleVectorInst(SVI->getOperand(0),
|
|
SVI->getOperand(1),
|
|
SVI->getOperand(2), "", InsertPt);
|
|
}
|
|
|
|
UI->replaceUsesOfWith(SVI, InsertedShuffle);
|
|
MadeChange = true;
|
|
}
|
|
|
|
// If we removed all uses, nuke the shuffle.
|
|
if (SVI->use_empty()) {
|
|
SVI->eraseFromParent();
|
|
MadeChange = true;
|
|
}
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
namespace {
|
|
/// \brief Helper class to promote a scalar operation to a vector one.
|
|
/// This class is used to move downward extractelement transition.
|
|
/// E.g.,
|
|
/// a = vector_op <2 x i32>
|
|
/// b = extractelement <2 x i32> a, i32 0
|
|
/// c = scalar_op b
|
|
/// store c
|
|
///
|
|
/// =>
|
|
/// a = vector_op <2 x i32>
|
|
/// c = vector_op a (equivalent to scalar_op on the related lane)
|
|
/// * d = extractelement <2 x i32> c, i32 0
|
|
/// * store d
|
|
/// Assuming both extractelement and store can be combine, we get rid of the
|
|
/// transition.
|
|
class VectorPromoteHelper {
|
|
/// Used to perform some checks on the legality of vector operations.
|
|
const TargetLowering &TLI;
|
|
|
|
/// Used to estimated the cost of the promoted chain.
|
|
const TargetTransformInfo &TTI;
|
|
|
|
/// The transition being moved downwards.
|
|
Instruction *Transition;
|
|
/// The sequence of instructions to be promoted.
|
|
SmallVector<Instruction *, 4> InstsToBePromoted;
|
|
/// Cost of combining a store and an extract.
|
|
unsigned StoreExtractCombineCost;
|
|
/// Instruction that will be combined with the transition.
|
|
Instruction *CombineInst;
|
|
|
|
/// \brief The instruction that represents the current end of the transition.
|
|
/// Since we are faking the promotion until we reach the end of the chain
|
|
/// of computation, we need a way to get the current end of the transition.
|
|
Instruction *getEndOfTransition() const {
|
|
if (InstsToBePromoted.empty())
|
|
return Transition;
|
|
return InstsToBePromoted.back();
|
|
}
|
|
|
|
/// \brief Return the index of the original value in the transition.
|
|
/// E.g., for "extractelement <2 x i32> c, i32 1" the original value,
|
|
/// c, is at index 0.
|
|
unsigned getTransitionOriginalValueIdx() const {
|
|
assert(isa<ExtractElementInst>(Transition) &&
|
|
"Other kind of transitions are not supported yet");
|
|
return 0;
|
|
}
|
|
|
|
/// \brief Return the index of the index in the transition.
|
|
/// E.g., for "extractelement <2 x i32> c, i32 0" the index
|
|
/// is at index 1.
|
|
unsigned getTransitionIdx() const {
|
|
assert(isa<ExtractElementInst>(Transition) &&
|
|
"Other kind of transitions are not supported yet");
|
|
return 1;
|
|
}
|
|
|
|
/// \brief Get the type of the transition.
|
|
/// This is the type of the original value.
|
|
/// E.g., for "extractelement <2 x i32> c, i32 1" the type of the
|
|
/// transition is <2 x i32>.
|
|
Type *getTransitionType() const {
|
|
return Transition->getOperand(getTransitionOriginalValueIdx())->getType();
|
|
}
|
|
|
|
/// \brief Promote \p ToBePromoted by moving \p Def downward through.
|
|
/// I.e., we have the following sequence:
|
|
/// Def = Transition <ty1> a to <ty2>
|
|
/// b = ToBePromoted <ty2> Def, ...
|
|
/// =>
|
|
/// b = ToBePromoted <ty1> a, ...
|
|
/// Def = Transition <ty1> ToBePromoted to <ty2>
|
|
void promoteImpl(Instruction *ToBePromoted);
|
|
|
|
/// \brief Check whether or not it is profitable to promote all the
|
|
/// instructions enqueued to be promoted.
|
|
bool isProfitableToPromote() {
|
|
Value *ValIdx = Transition->getOperand(getTransitionOriginalValueIdx());
|
|
unsigned Index = isa<ConstantInt>(ValIdx)
|
|
? cast<ConstantInt>(ValIdx)->getZExtValue()
|
|
: -1;
|
|
Type *PromotedType = getTransitionType();
|
|
|
|
StoreInst *ST = cast<StoreInst>(CombineInst);
|
|
unsigned AS = ST->getPointerAddressSpace();
|
|
unsigned Align = ST->getAlignment();
|
|
// Check if this store is supported.
|
|
if (!TLI.allowsMisalignedMemoryAccesses(
|
|
TLI.getValueType(ST->getValueOperand()->getType()), AS, Align)) {
|
|
// If this is not supported, there is no way we can combine
|
|
// the extract with the store.
|
|
return false;
|
|
}
|
|
|
|
// The scalar chain of computation has to pay for the transition
|
|
// scalar to vector.
|
|
// The vector chain has to account for the combining cost.
|
|
uint64_t ScalarCost =
|
|
TTI.getVectorInstrCost(Transition->getOpcode(), PromotedType, Index);
|
|
uint64_t VectorCost = StoreExtractCombineCost;
|
|
for (const auto &Inst : InstsToBePromoted) {
|
|
// Compute the cost.
|
|
// By construction, all instructions being promoted are arithmetic ones.
|
|
// Moreover, one argument is a constant that can be viewed as a splat
|
|
// constant.
|
|
Value *Arg0 = Inst->getOperand(0);
|
|
bool IsArg0Constant = isa<UndefValue>(Arg0) || isa<ConstantInt>(Arg0) ||
|
|
isa<ConstantFP>(Arg0);
|
|
TargetTransformInfo::OperandValueKind Arg0OVK =
|
|
IsArg0Constant ? TargetTransformInfo::OK_UniformConstantValue
|
|
: TargetTransformInfo::OK_AnyValue;
|
|
TargetTransformInfo::OperandValueKind Arg1OVK =
|
|
!IsArg0Constant ? TargetTransformInfo::OK_UniformConstantValue
|
|
: TargetTransformInfo::OK_AnyValue;
|
|
ScalarCost += TTI.getArithmeticInstrCost(
|
|
Inst->getOpcode(), Inst->getType(), Arg0OVK, Arg1OVK);
|
|
VectorCost += TTI.getArithmeticInstrCost(Inst->getOpcode(), PromotedType,
|
|
Arg0OVK, Arg1OVK);
|
|
}
|
|
DEBUG(dbgs() << "Estimated cost of computation to be promoted:\nScalar: "
|
|
<< ScalarCost << "\nVector: " << VectorCost << '\n');
|
|
return ScalarCost > VectorCost;
|
|
}
|
|
|
|
/// \brief Generate a constant vector with \p Val with the same
|
|
/// number of elements as the transition.
|
|
/// \p UseSplat defines whether or not \p Val should be replicated
|
|
/// accross the whole vector.
|
|
/// In other words, if UseSplat == true, we generate <Val, Val, ..., Val>,
|
|
/// otherwise we generate a vector with as many undef as possible:
|
|
/// <undef, ..., undef, Val, undef, ..., undef> where \p Val is only
|
|
/// used at the index of the extract.
|
|
Value *getConstantVector(Constant *Val, bool UseSplat) const {
|
|
unsigned ExtractIdx = UINT_MAX;
|
|
if (!UseSplat) {
|
|
// If we cannot determine where the constant must be, we have to
|
|
// use a splat constant.
|
|
Value *ValExtractIdx = Transition->getOperand(getTransitionIdx());
|
|
if (ConstantInt *CstVal = dyn_cast<ConstantInt>(ValExtractIdx))
|
|
ExtractIdx = CstVal->getSExtValue();
|
|
else
|
|
UseSplat = true;
|
|
}
|
|
|
|
unsigned End = getTransitionType()->getVectorNumElements();
|
|
if (UseSplat)
|
|
return ConstantVector::getSplat(End, Val);
|
|
|
|
SmallVector<Constant *, 4> ConstVec;
|
|
UndefValue *UndefVal = UndefValue::get(Val->getType());
|
|
for (unsigned Idx = 0; Idx != End; ++Idx) {
|
|
if (Idx == ExtractIdx)
|
|
ConstVec.push_back(Val);
|
|
else
|
|
ConstVec.push_back(UndefVal);
|
|
}
|
|
return ConstantVector::get(ConstVec);
|
|
}
|
|
|
|
/// \brief Check if promoting to a vector type an operand at \p OperandIdx
|
|
/// in \p Use can trigger undefined behavior.
|
|
static bool canCauseUndefinedBehavior(const Instruction *Use,
|
|
unsigned OperandIdx) {
|
|
// This is not safe to introduce undef when the operand is on
|
|
// the right hand side of a division-like instruction.
|
|
if (OperandIdx != 1)
|
|
return false;
|
|
switch (Use->getOpcode()) {
|
|
default:
|
|
return false;
|
|
case Instruction::SDiv:
|
|
case Instruction::UDiv:
|
|
case Instruction::SRem:
|
|
case Instruction::URem:
|
|
return true;
|
|
case Instruction::FDiv:
|
|
case Instruction::FRem:
|
|
return !Use->hasNoNaNs();
|
|
}
|
|
llvm_unreachable(nullptr);
|
|
}
|
|
|
|
public:
|
|
VectorPromoteHelper(const TargetLowering &TLI, const TargetTransformInfo &TTI,
|
|
Instruction *Transition, unsigned CombineCost)
|
|
: TLI(TLI), TTI(TTI), Transition(Transition),
|
|
StoreExtractCombineCost(CombineCost), CombineInst(nullptr) {
|
|
assert(Transition && "Do not know how to promote null");
|
|
}
|
|
|
|
/// \brief Check if we can promote \p ToBePromoted to \p Type.
|
|
bool canPromote(const Instruction *ToBePromoted) const {
|
|
// We could support CastInst too.
|
|
return isa<BinaryOperator>(ToBePromoted);
|
|
}
|
|
|
|
/// \brief Check if it is profitable to promote \p ToBePromoted
|
|
/// by moving downward the transition through.
|
|
bool shouldPromote(const Instruction *ToBePromoted) const {
|
|
// Promote only if all the operands can be statically expanded.
|
|
// Indeed, we do not want to introduce any new kind of transitions.
|
|
for (const Use &U : ToBePromoted->operands()) {
|
|
const Value *Val = U.get();
|
|
if (Val == getEndOfTransition()) {
|
|
// If the use is a division and the transition is on the rhs,
|
|
// we cannot promote the operation, otherwise we may create a
|
|
// division by zero.
|
|
if (canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo()))
|
|
return false;
|
|
continue;
|
|
}
|
|
if (!isa<ConstantInt>(Val) && !isa<UndefValue>(Val) &&
|
|
!isa<ConstantFP>(Val))
|
|
return false;
|
|
}
|
|
// Check that the resulting operation is legal.
|
|
int ISDOpcode = TLI.InstructionOpcodeToISD(ToBePromoted->getOpcode());
|
|
if (!ISDOpcode)
|
|
return false;
|
|
return StressStoreExtract ||
|
|
TLI.isOperationLegalOrCustom(
|
|
ISDOpcode, TLI.getValueType(getTransitionType(), true));
|
|
}
|
|
|
|
/// \brief Check whether or not \p Use can be combined
|
|
/// with the transition.
|
|
/// I.e., is it possible to do Use(Transition) => AnotherUse?
|
|
bool canCombine(const Instruction *Use) { return isa<StoreInst>(Use); }
|
|
|
|
/// \brief Record \p ToBePromoted as part of the chain to be promoted.
|
|
void enqueueForPromotion(Instruction *ToBePromoted) {
|
|
InstsToBePromoted.push_back(ToBePromoted);
|
|
}
|
|
|
|
/// \brief Set the instruction that will be combined with the transition.
|
|
void recordCombineInstruction(Instruction *ToBeCombined) {
|
|
assert(canCombine(ToBeCombined) && "Unsupported instruction to combine");
|
|
CombineInst = ToBeCombined;
|
|
}
|
|
|
|
/// \brief Promote all the instructions enqueued for promotion if it is
|
|
/// is profitable.
|
|
/// \return True if the promotion happened, false otherwise.
|
|
bool promote() {
|
|
// Check if there is something to promote.
|
|
// Right now, if we do not have anything to combine with,
|
|
// we assume the promotion is not profitable.
|
|
if (InstsToBePromoted.empty() || !CombineInst)
|
|
return false;
|
|
|
|
// Check cost.
|
|
if (!StressStoreExtract && !isProfitableToPromote())
|
|
return false;
|
|
|
|
// Promote.
|
|
for (auto &ToBePromoted : InstsToBePromoted)
|
|
promoteImpl(ToBePromoted);
|
|
InstsToBePromoted.clear();
|
|
return true;
|
|
}
|
|
};
|
|
} // End of anonymous namespace.
|
|
|
|
void VectorPromoteHelper::promoteImpl(Instruction *ToBePromoted) {
|
|
// At this point, we know that all the operands of ToBePromoted but Def
|
|
// can be statically promoted.
|
|
// For Def, we need to use its parameter in ToBePromoted:
|
|
// b = ToBePromoted ty1 a
|
|
// Def = Transition ty1 b to ty2
|
|
// Move the transition down.
|
|
// 1. Replace all uses of the promoted operation by the transition.
|
|
// = ... b => = ... Def.
|
|
assert(ToBePromoted->getType() == Transition->getType() &&
|
|
"The type of the result of the transition does not match "
|
|
"the final type");
|
|
ToBePromoted->replaceAllUsesWith(Transition);
|
|
// 2. Update the type of the uses.
|
|
// b = ToBePromoted ty2 Def => b = ToBePromoted ty1 Def.
|
|
Type *TransitionTy = getTransitionType();
|
|
ToBePromoted->mutateType(TransitionTy);
|
|
// 3. Update all the operands of the promoted operation with promoted
|
|
// operands.
|
|
// b = ToBePromoted ty1 Def => b = ToBePromoted ty1 a.
|
|
for (Use &U : ToBePromoted->operands()) {
|
|
Value *Val = U.get();
|
|
Value *NewVal = nullptr;
|
|
if (Val == Transition)
|
|
NewVal = Transition->getOperand(getTransitionOriginalValueIdx());
|
|
else if (isa<UndefValue>(Val) || isa<ConstantInt>(Val) ||
|
|
isa<ConstantFP>(Val)) {
|
|
// Use a splat constant if it is not safe to use undef.
|
|
NewVal = getConstantVector(
|
|
cast<Constant>(Val),
|
|
isa<UndefValue>(Val) ||
|
|
canCauseUndefinedBehavior(ToBePromoted, U.getOperandNo()));
|
|
} else
|
|
llvm_unreachable("Did you modified shouldPromote and forgot to update "
|
|
"this?");
|
|
ToBePromoted->setOperand(U.getOperandNo(), NewVal);
|
|
}
|
|
Transition->removeFromParent();
|
|
Transition->insertAfter(ToBePromoted);
|
|
Transition->setOperand(getTransitionOriginalValueIdx(), ToBePromoted);
|
|
}
|
|
|
|
/// Some targets can do store(extractelement) with one instruction.
|
|
/// Try to push the extractelement towards the stores when the target
|
|
/// has this feature and this is profitable.
|
|
bool CodeGenPrepare::OptimizeExtractElementInst(Instruction *Inst) {
|
|
unsigned CombineCost = UINT_MAX;
|
|
if (DisableStoreExtract || !TLI ||
|
|
(!StressStoreExtract &&
|
|
!TLI->canCombineStoreAndExtract(Inst->getOperand(0)->getType(),
|
|
Inst->getOperand(1), CombineCost)))
|
|
return false;
|
|
|
|
// At this point we know that Inst is a vector to scalar transition.
|
|
// Try to move it down the def-use chain, until:
|
|
// - We can combine the transition with its single use
|
|
// => we got rid of the transition.
|
|
// - We escape the current basic block
|
|
// => we would need to check that we are moving it at a cheaper place and
|
|
// we do not do that for now.
|
|
BasicBlock *Parent = Inst->getParent();
|
|
DEBUG(dbgs() << "Found an interesting transition: " << *Inst << '\n');
|
|
VectorPromoteHelper VPH(*TLI, *TTI, Inst, CombineCost);
|
|
// If the transition has more than one use, assume this is not going to be
|
|
// beneficial.
|
|
while (Inst->hasOneUse()) {
|
|
Instruction *ToBePromoted = cast<Instruction>(*Inst->user_begin());
|
|
DEBUG(dbgs() << "Use: " << *ToBePromoted << '\n');
|
|
|
|
if (ToBePromoted->getParent() != Parent) {
|
|
DEBUG(dbgs() << "Instruction to promote is in a different block ("
|
|
<< ToBePromoted->getParent()->getName()
|
|
<< ") than the transition (" << Parent->getName() << ").\n");
|
|
return false;
|
|
}
|
|
|
|
if (VPH.canCombine(ToBePromoted)) {
|
|
DEBUG(dbgs() << "Assume " << *Inst << '\n'
|
|
<< "will be combined with: " << *ToBePromoted << '\n');
|
|
VPH.recordCombineInstruction(ToBePromoted);
|
|
bool Changed = VPH.promote();
|
|
NumStoreExtractExposed += Changed;
|
|
return Changed;
|
|
}
|
|
|
|
DEBUG(dbgs() << "Try promoting.\n");
|
|
if (!VPH.canPromote(ToBePromoted) || !VPH.shouldPromote(ToBePromoted))
|
|
return false;
|
|
|
|
DEBUG(dbgs() << "Promoting is possible... Enqueue for promotion!\n");
|
|
|
|
VPH.enqueueForPromotion(ToBePromoted);
|
|
Inst = ToBePromoted;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
bool CodeGenPrepare::OptimizeInst(Instruction *I, bool& ModifiedDT) {
|
|
if (PHINode *P = dyn_cast<PHINode>(I)) {
|
|
// It is possible for very late stage optimizations (such as SimplifyCFG)
|
|
// to introduce PHI nodes too late to be cleaned up. If we detect such a
|
|
// trivial PHI, go ahead and zap it here.
|
|
if (Value *V = SimplifyInstruction(P, TLI ? TLI->getDataLayout() : nullptr,
|
|
TLInfo, DT)) {
|
|
P->replaceAllUsesWith(V);
|
|
P->eraseFromParent();
|
|
++NumPHIsElim;
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
if (CastInst *CI = dyn_cast<CastInst>(I)) {
|
|
// If the source of the cast is a constant, then this should have
|
|
// already been constant folded. The only reason NOT to constant fold
|
|
// it is if something (e.g. LSR) was careful to place the constant
|
|
// evaluation in a block other than then one that uses it (e.g. to hoist
|
|
// the address of globals out of a loop). If this is the case, we don't
|
|
// want to forward-subst the cast.
|
|
if (isa<Constant>(CI->getOperand(0)))
|
|
return false;
|
|
|
|
if (TLI && OptimizeNoopCopyExpression(CI, *TLI))
|
|
return true;
|
|
|
|
if (isa<ZExtInst>(I) || isa<SExtInst>(I)) {
|
|
/// Sink a zext or sext into its user blocks if the target type doesn't
|
|
/// fit in one register
|
|
if (TLI && TLI->getTypeAction(CI->getContext(),
|
|
TLI->getValueType(CI->getType())) ==
|
|
TargetLowering::TypeExpandInteger) {
|
|
return SinkCast(CI);
|
|
} else {
|
|
bool MadeChange = MoveExtToFormExtLoad(I);
|
|
return MadeChange | OptimizeExtUses(I);
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
if (CmpInst *CI = dyn_cast<CmpInst>(I))
|
|
if (!TLI || !TLI->hasMultipleConditionRegisters())
|
|
return OptimizeCmpExpression(CI);
|
|
|
|
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
|
|
if (TLI)
|
|
return OptimizeMemoryInst(I, I->getOperand(0), LI->getType());
|
|
return false;
|
|
}
|
|
|
|
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
|
|
if (TLI)
|
|
return OptimizeMemoryInst(I, SI->getOperand(1),
|
|
SI->getOperand(0)->getType());
|
|
return false;
|
|
}
|
|
|
|
BinaryOperator *BinOp = dyn_cast<BinaryOperator>(I);
|
|
|
|
if (BinOp && (BinOp->getOpcode() == Instruction::AShr ||
|
|
BinOp->getOpcode() == Instruction::LShr)) {
|
|
ConstantInt *CI = dyn_cast<ConstantInt>(BinOp->getOperand(1));
|
|
if (TLI && CI && TLI->hasExtractBitsInsn())
|
|
return OptimizeExtractBits(BinOp, CI, *TLI);
|
|
|
|
return false;
|
|
}
|
|
|
|
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(I)) {
|
|
if (GEPI->hasAllZeroIndices()) {
|
|
/// The GEP operand must be a pointer, so must its result -> BitCast
|
|
Instruction *NC = new BitCastInst(GEPI->getOperand(0), GEPI->getType(),
|
|
GEPI->getName(), GEPI);
|
|
GEPI->replaceAllUsesWith(NC);
|
|
GEPI->eraseFromParent();
|
|
++NumGEPsElim;
|
|
OptimizeInst(NC, ModifiedDT);
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
if (CallInst *CI = dyn_cast<CallInst>(I))
|
|
return OptimizeCallInst(CI, ModifiedDT);
|
|
|
|
if (SelectInst *SI = dyn_cast<SelectInst>(I))
|
|
return OptimizeSelectInst(SI);
|
|
|
|
if (ShuffleVectorInst *SVI = dyn_cast<ShuffleVectorInst>(I))
|
|
return OptimizeShuffleVectorInst(SVI);
|
|
|
|
if (isa<ExtractElementInst>(I))
|
|
return OptimizeExtractElementInst(I);
|
|
|
|
return false;
|
|
}
|
|
|
|
// In this pass we look for GEP and cast instructions that are used
|
|
// across basic blocks and rewrite them to improve basic-block-at-a-time
|
|
// selection.
|
|
bool CodeGenPrepare::OptimizeBlock(BasicBlock &BB, bool& ModifiedDT) {
|
|
SunkAddrs.clear();
|
|
bool MadeChange = false;
|
|
|
|
CurInstIterator = BB.begin();
|
|
while (CurInstIterator != BB.end()) {
|
|
MadeChange |= OptimizeInst(CurInstIterator++, ModifiedDT);
|
|
if (ModifiedDT)
|
|
return true;
|
|
}
|
|
MadeChange |= DupRetToEnableTailCallOpts(&BB);
|
|
|
|
return MadeChange;
|
|
}
|
|
|
|
// llvm.dbg.value is far away from the value then iSel may not be able
|
|
// handle it properly. iSel will drop llvm.dbg.value if it can not
|
|
// find a node corresponding to the value.
|
|
bool CodeGenPrepare::PlaceDbgValues(Function &F) {
|
|
bool MadeChange = false;
|
|
for (BasicBlock &BB : F) {
|
|
Instruction *PrevNonDbgInst = nullptr;
|
|
for (BasicBlock::iterator BI = BB.begin(), BE = BB.end(); BI != BE;) {
|
|
Instruction *Insn = BI++;
|
|
DbgValueInst *DVI = dyn_cast<DbgValueInst>(Insn);
|
|
// Leave dbg.values that refer to an alloca alone. These
|
|
// instrinsics describe the address of a variable (= the alloca)
|
|
// being taken. They should not be moved next to the alloca
|
|
// (and to the beginning of the scope), but rather stay close to
|
|
// where said address is used.
|
|
if (!DVI || (DVI->getValue() && isa<AllocaInst>(DVI->getValue()))) {
|
|
PrevNonDbgInst = Insn;
|
|
continue;
|
|
}
|
|
|
|
Instruction *VI = dyn_cast_or_null<Instruction>(DVI->getValue());
|
|
if (VI && VI != PrevNonDbgInst && !VI->isTerminator()) {
|
|
DEBUG(dbgs() << "Moving Debug Value before :\n" << *DVI << ' ' << *VI);
|
|
DVI->removeFromParent();
|
|
if (isa<PHINode>(VI))
|
|
DVI->insertBefore(VI->getParent()->getFirstInsertionPt());
|
|
else
|
|
DVI->insertAfter(VI);
|
|
MadeChange = true;
|
|
++NumDbgValueMoved;
|
|
}
|
|
}
|
|
}
|
|
return MadeChange;
|
|
}
|
|
|
|
// If there is a sequence that branches based on comparing a single bit
|
|
// against zero that can be combined into a single instruction, and the
|
|
// target supports folding these into a single instruction, sink the
|
|
// mask and compare into the branch uses. Do this before OptimizeBlock ->
|
|
// OptimizeInst -> OptimizeCmpExpression, which perturbs the pattern being
|
|
// searched for.
|
|
bool CodeGenPrepare::sinkAndCmp(Function &F) {
|
|
if (!EnableAndCmpSinking)
|
|
return false;
|
|
if (!TLI || !TLI->isMaskAndBranchFoldingLegal())
|
|
return false;
|
|
bool MadeChange = false;
|
|
for (Function::iterator I = F.begin(), E = F.end(); I != E; ) {
|
|
BasicBlock *BB = I++;
|
|
|
|
// Does this BB end with the following?
|
|
// %andVal = and %val, #single-bit-set
|
|
// %icmpVal = icmp %andResult, 0
|
|
// br i1 %cmpVal label %dest1, label %dest2"
|
|
BranchInst *Brcc = dyn_cast<BranchInst>(BB->getTerminator());
|
|
if (!Brcc || !Brcc->isConditional())
|
|
continue;
|
|
ICmpInst *Cmp = dyn_cast<ICmpInst>(Brcc->getOperand(0));
|
|
if (!Cmp || Cmp->getParent() != BB)
|
|
continue;
|
|
ConstantInt *Zero = dyn_cast<ConstantInt>(Cmp->getOperand(1));
|
|
if (!Zero || !Zero->isZero())
|
|
continue;
|
|
Instruction *And = dyn_cast<Instruction>(Cmp->getOperand(0));
|
|
if (!And || And->getOpcode() != Instruction::And || And->getParent() != BB)
|
|
continue;
|
|
ConstantInt* Mask = dyn_cast<ConstantInt>(And->getOperand(1));
|
|
if (!Mask || !Mask->getUniqueInteger().isPowerOf2())
|
|
continue;
|
|
DEBUG(dbgs() << "found and; icmp ?,0; brcc\n"); DEBUG(BB->dump());
|
|
|
|
// Push the "and; icmp" for any users that are conditional branches.
|
|
// Since there can only be one branch use per BB, we don't need to keep
|
|
// track of which BBs we insert into.
|
|
for (Value::use_iterator UI = Cmp->use_begin(), E = Cmp->use_end();
|
|
UI != E; ) {
|
|
Use &TheUse = *UI;
|
|
// Find brcc use.
|
|
BranchInst *BrccUser = dyn_cast<BranchInst>(*UI);
|
|
++UI;
|
|
if (!BrccUser || !BrccUser->isConditional())
|
|
continue;
|
|
BasicBlock *UserBB = BrccUser->getParent();
|
|
if (UserBB == BB) continue;
|
|
DEBUG(dbgs() << "found Brcc use\n");
|
|
|
|
// Sink the "and; icmp" to use.
|
|
MadeChange = true;
|
|
BinaryOperator *NewAnd =
|
|
BinaryOperator::CreateAnd(And->getOperand(0), And->getOperand(1), "",
|
|
BrccUser);
|
|
CmpInst *NewCmp =
|
|
CmpInst::Create(Cmp->getOpcode(), Cmp->getPredicate(), NewAnd, Zero,
|
|
"", BrccUser);
|
|
TheUse = NewCmp;
|
|
++NumAndCmpsMoved;
|
|
DEBUG(BrccUser->getParent()->dump());
|
|
}
|
|
}
|
|
return MadeChange;
|
|
}
|
|
|
|
/// \brief Retrieve the probabilities of a conditional branch. Returns true on
|
|
/// success, or returns false if no or invalid metadata was found.
|
|
static bool extractBranchMetadata(BranchInst *BI,
|
|
uint64_t &ProbTrue, uint64_t &ProbFalse) {
|
|
assert(BI->isConditional() &&
|
|
"Looking for probabilities on unconditional branch?");
|
|
auto *ProfileData = BI->getMetadata(LLVMContext::MD_prof);
|
|
if (!ProfileData || ProfileData->getNumOperands() != 3)
|
|
return false;
|
|
|
|
const auto *CITrue =
|
|
mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(1));
|
|
const auto *CIFalse =
|
|
mdconst::dyn_extract<ConstantInt>(ProfileData->getOperand(2));
|
|
if (!CITrue || !CIFalse)
|
|
return false;
|
|
|
|
ProbTrue = CITrue->getValue().getZExtValue();
|
|
ProbFalse = CIFalse->getValue().getZExtValue();
|
|
|
|
return true;
|
|
}
|
|
|
|
/// \brief Scale down both weights to fit into uint32_t.
|
|
static void scaleWeights(uint64_t &NewTrue, uint64_t &NewFalse) {
|
|
uint64_t NewMax = (NewTrue > NewFalse) ? NewTrue : NewFalse;
|
|
uint32_t Scale = (NewMax / UINT32_MAX) + 1;
|
|
NewTrue = NewTrue / Scale;
|
|
NewFalse = NewFalse / Scale;
|
|
}
|
|
|
|
/// \brief Some targets prefer to split a conditional branch like:
|
|
/// \code
|
|
/// %0 = icmp ne i32 %a, 0
|
|
/// %1 = icmp ne i32 %b, 0
|
|
/// %or.cond = or i1 %0, %1
|
|
/// br i1 %or.cond, label %TrueBB, label %FalseBB
|
|
/// \endcode
|
|
/// into multiple branch instructions like:
|
|
/// \code
|
|
/// bb1:
|
|
/// %0 = icmp ne i32 %a, 0
|
|
/// br i1 %0, label %TrueBB, label %bb2
|
|
/// bb2:
|
|
/// %1 = icmp ne i32 %b, 0
|
|
/// br i1 %1, label %TrueBB, label %FalseBB
|
|
/// \endcode
|
|
/// This usually allows instruction selection to do even further optimizations
|
|
/// and combine the compare with the branch instruction. Currently this is
|
|
/// applied for targets which have "cheap" jump instructions.
|
|
///
|
|
/// FIXME: Remove the (equivalent?) implementation in SelectionDAG.
|
|
///
|
|
bool CodeGenPrepare::splitBranchCondition(Function &F) {
|
|
if (!TM || !TM->Options.EnableFastISel || !TLI || TLI->isJumpExpensive())
|
|
return false;
|
|
|
|
bool MadeChange = false;
|
|
for (auto &BB : F) {
|
|
// Does this BB end with the following?
|
|
// %cond1 = icmp|fcmp|binary instruction ...
|
|
// %cond2 = icmp|fcmp|binary instruction ...
|
|
// %cond.or = or|and i1 %cond1, cond2
|
|
// br i1 %cond.or label %dest1, label %dest2"
|
|
BinaryOperator *LogicOp;
|
|
BasicBlock *TBB, *FBB;
|
|
if (!match(BB.getTerminator(), m_Br(m_OneUse(m_BinOp(LogicOp)), TBB, FBB)))
|
|
continue;
|
|
|
|
unsigned Opc;
|
|
Value *Cond1, *Cond2;
|
|
if (match(LogicOp, m_And(m_OneUse(m_Value(Cond1)),
|
|
m_OneUse(m_Value(Cond2)))))
|
|
Opc = Instruction::And;
|
|
else if (match(LogicOp, m_Or(m_OneUse(m_Value(Cond1)),
|
|
m_OneUse(m_Value(Cond2)))))
|
|
Opc = Instruction::Or;
|
|
else
|
|
continue;
|
|
|
|
if (!match(Cond1, m_CombineOr(m_Cmp(), m_BinOp())) ||
|
|
!match(Cond2, m_CombineOr(m_Cmp(), m_BinOp())) )
|
|
continue;
|
|
|
|
DEBUG(dbgs() << "Before branch condition splitting\n"; BB.dump());
|
|
|
|
// Create a new BB.
|
|
auto *InsertBefore = std::next(Function::iterator(BB))
|
|
.getNodePtrUnchecked();
|
|
auto TmpBB = BasicBlock::Create(BB.getContext(),
|
|
BB.getName() + ".cond.split",
|
|
BB.getParent(), InsertBefore);
|
|
|
|
// Update original basic block by using the first condition directly by the
|
|
// branch instruction and removing the no longer needed and/or instruction.
|
|
auto *Br1 = cast<BranchInst>(BB.getTerminator());
|
|
Br1->setCondition(Cond1);
|
|
LogicOp->eraseFromParent();
|
|
|
|
// Depending on the conditon we have to either replace the true or the false
|
|
// successor of the original branch instruction.
|
|
if (Opc == Instruction::And)
|
|
Br1->setSuccessor(0, TmpBB);
|
|
else
|
|
Br1->setSuccessor(1, TmpBB);
|
|
|
|
// Fill in the new basic block.
|
|
auto *Br2 = IRBuilder<>(TmpBB).CreateCondBr(Cond2, TBB, FBB);
|
|
if (auto *I = dyn_cast<Instruction>(Cond2)) {
|
|
I->removeFromParent();
|
|
I->insertBefore(Br2);
|
|
}
|
|
|
|
// Update PHI nodes in both successors. The original BB needs to be
|
|
// replaced in one succesor's PHI nodes, because the branch comes now from
|
|
// the newly generated BB (NewBB). In the other successor we need to add one
|
|
// incoming edge to the PHI nodes, because both branch instructions target
|
|
// now the same successor. Depending on the original branch condition
|
|
// (and/or) we have to swap the successors (TrueDest, FalseDest), so that
|
|
// we perfrom the correct update for the PHI nodes.
|
|
// This doesn't change the successor order of the just created branch
|
|
// instruction (or any other instruction).
|
|
if (Opc == Instruction::Or)
|
|
std::swap(TBB, FBB);
|
|
|
|
// Replace the old BB with the new BB.
|
|
for (auto &I : *TBB) {
|
|
PHINode *PN = dyn_cast<PHINode>(&I);
|
|
if (!PN)
|
|
break;
|
|
int i;
|
|
while ((i = PN->getBasicBlockIndex(&BB)) >= 0)
|
|
PN->setIncomingBlock(i, TmpBB);
|
|
}
|
|
|
|
// Add another incoming edge form the new BB.
|
|
for (auto &I : *FBB) {
|
|
PHINode *PN = dyn_cast<PHINode>(&I);
|
|
if (!PN)
|
|
break;
|
|
auto *Val = PN->getIncomingValueForBlock(&BB);
|
|
PN->addIncoming(Val, TmpBB);
|
|
}
|
|
|
|
// Update the branch weights (from SelectionDAGBuilder::
|
|
// FindMergedConditions).
|
|
if (Opc == Instruction::Or) {
|
|
// Codegen X | Y as:
|
|
// BB1:
|
|
// jmp_if_X TBB
|
|
// jmp TmpBB
|
|
// TmpBB:
|
|
// jmp_if_Y TBB
|
|
// jmp FBB
|
|
//
|
|
|
|
// We have flexibility in setting Prob for BB1 and Prob for NewBB.
|
|
// The requirement is that
|
|
// TrueProb for BB1 + (FalseProb for BB1 * TrueProb for TmpBB)
|
|
// = TrueProb for orignal BB.
|
|
// Assuming the orignal weights are A and B, one choice is to set BB1's
|
|
// weights to A and A+2B, and set TmpBB's weights to A and 2B. This choice
|
|
// assumes that
|
|
// TrueProb for BB1 == FalseProb for BB1 * TrueProb for TmpBB.
|
|
// Another choice is to assume TrueProb for BB1 equals to TrueProb for
|
|
// TmpBB, but the math is more complicated.
|
|
uint64_t TrueWeight, FalseWeight;
|
|
if (extractBranchMetadata(Br1, TrueWeight, FalseWeight)) {
|
|
uint64_t NewTrueWeight = TrueWeight;
|
|
uint64_t NewFalseWeight = TrueWeight + 2 * FalseWeight;
|
|
scaleWeights(NewTrueWeight, NewFalseWeight);
|
|
Br1->setMetadata(LLVMContext::MD_prof, MDBuilder(Br1->getContext())
|
|
.createBranchWeights(TrueWeight, FalseWeight));
|
|
|
|
NewTrueWeight = TrueWeight;
|
|
NewFalseWeight = 2 * FalseWeight;
|
|
scaleWeights(NewTrueWeight, NewFalseWeight);
|
|
Br2->setMetadata(LLVMContext::MD_prof, MDBuilder(Br2->getContext())
|
|
.createBranchWeights(TrueWeight, FalseWeight));
|
|
}
|
|
} else {
|
|
// Codegen X & Y as:
|
|
// BB1:
|
|
// jmp_if_X TmpBB
|
|
// jmp FBB
|
|
// TmpBB:
|
|
// jmp_if_Y TBB
|
|
// jmp FBB
|
|
//
|
|
// This requires creation of TmpBB after CurBB.
|
|
|
|
// We have flexibility in setting Prob for BB1 and Prob for TmpBB.
|
|
// The requirement is that
|
|
// FalseProb for BB1 + (TrueProb for BB1 * FalseProb for TmpBB)
|
|
// = FalseProb for orignal BB.
|
|
// Assuming the orignal weights are A and B, one choice is to set BB1's
|
|
// weights to 2A+B and B, and set TmpBB's weights to 2A and B. This choice
|
|
// assumes that
|
|
// FalseProb for BB1 == TrueProb for BB1 * FalseProb for TmpBB.
|
|
uint64_t TrueWeight, FalseWeight;
|
|
if (extractBranchMetadata(Br1, TrueWeight, FalseWeight)) {
|
|
uint64_t NewTrueWeight = 2 * TrueWeight + FalseWeight;
|
|
uint64_t NewFalseWeight = FalseWeight;
|
|
scaleWeights(NewTrueWeight, NewFalseWeight);
|
|
Br1->setMetadata(LLVMContext::MD_prof, MDBuilder(Br1->getContext())
|
|
.createBranchWeights(TrueWeight, FalseWeight));
|
|
|
|
NewTrueWeight = 2 * TrueWeight;
|
|
NewFalseWeight = FalseWeight;
|
|
scaleWeights(NewTrueWeight, NewFalseWeight);
|
|
Br2->setMetadata(LLVMContext::MD_prof, MDBuilder(Br2->getContext())
|
|
.createBranchWeights(TrueWeight, FalseWeight));
|
|
}
|
|
}
|
|
|
|
// Request DOM Tree update.
|
|
// Note: No point in getting fancy here, since the DT info is never
|
|
// available to CodeGenPrepare and the existing update code is broken
|
|
// anyways.
|
|
ModifiedDT = true;
|
|
|
|
MadeChange = true;
|
|
|
|
DEBUG(dbgs() << "After branch condition splitting\n"; BB.dump();
|
|
TmpBB->dump());
|
|
}
|
|
return MadeChange;
|
|
}
|