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https://github.com/c64scene-ar/llvm-6502.git
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Summary: DataLayout keeps the string used for its creation. As a side effect it is no longer needed in the Module. This is "almost" NFC, the string is no longer canonicalized, you can't rely on two "equals" DataLayout having the same string returned by getStringRepresentation(). Get rid of DataLayoutPass: the DataLayout is in the Module The DataLayout is "per-module", let's enforce this by not duplicating it more than necessary. One more step toward non-optionality of the DataLayout in the module. Make DataLayout Non-Optional in the Module Module->getDataLayout() will never returns nullptr anymore. Reviewers: echristo Subscribers: resistor, llvm-commits, jholewinski Differential Revision: http://reviews.llvm.org/D7992 From: Mehdi Amini <mehdi.amini@apple.com> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231270 91177308-0d34-0410-b5e6-96231b3b80d8
377 lines
12 KiB
C++
377 lines
12 KiB
C++
//===------ PPCLoopPreIncPrep.cpp - Loop Pre-Inc. AM Prep. Pass -----------===//
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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 file implements a pass to prepare loops for pre-increment addressing
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// modes. Additional PHIs are created for loop induction variables used by
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// load/store instructions so that the pre-increment forms can be used.
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// Generically, this means transforming loops like this:
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// for (int i = 0; i < n; ++i)
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// array[i] = c;
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// to look like this:
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// T *p = array[-1];
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// for (int i = 0; i < n; ++i)
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// *++p = c;
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "ppc-loop-preinc-prep"
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#include "PPC.h"
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#include "PPCTargetMachine.h"
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#include "llvm/ADT/STLExtras.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/CodeMetrics.h"
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#include "llvm/Analysis/InstructionSimplify.h"
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#include "llvm/Analysis/LoopInfo.h"
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#include "llvm/Analysis/ScalarEvolution.h"
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#include "llvm/Analysis/ScalarEvolutionExpander.h"
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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#include "llvm/Analysis/ValueTracking.h"
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#include "llvm/IR/CFG.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/IntrinsicInst.h"
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#include "llvm/IR/Module.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/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/BasicBlockUtils.h"
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#include "llvm/Transforms/Utils/Local.h"
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#include "llvm/Transforms/Utils/LoopUtils.h"
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#include "llvm/Transforms/Utils/ValueMapper.h"
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using namespace llvm;
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// By default, we limit this to creating 16 PHIs (which is a little over half
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// of the allocatable register set).
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static cl::opt<unsigned> MaxVars("ppc-preinc-prep-max-vars",
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cl::Hidden, cl::init(16),
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cl::desc("Potential PHI threshold for PPC preinc loop prep"));
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namespace llvm {
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void initializePPCLoopPreIncPrepPass(PassRegistry&);
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}
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namespace {
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class PPCLoopPreIncPrep : public FunctionPass {
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public:
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static char ID; // Pass ID, replacement for typeid
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PPCLoopPreIncPrep() : FunctionPass(ID), TM(nullptr) {
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initializePPCLoopPreIncPrepPass(*PassRegistry::getPassRegistry());
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}
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PPCLoopPreIncPrep(PPCTargetMachine &TM) : FunctionPass(ID), TM(&TM) {
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initializePPCLoopPreIncPrepPass(*PassRegistry::getPassRegistry());
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override {
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AU.addPreserved<DominatorTreeWrapperPass>();
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AU.addRequired<LoopInfoWrapperPass>();
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AU.addPreserved<LoopInfoWrapperPass>();
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AU.addRequired<ScalarEvolution>();
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}
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bool runOnFunction(Function &F) override;
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bool runOnLoop(Loop *L);
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void simplifyLoopLatch(Loop *L);
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bool rotateLoop(Loop *L);
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private:
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PPCTargetMachine *TM;
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LoopInfo *LI;
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ScalarEvolution *SE;
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};
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}
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char PPCLoopPreIncPrep::ID = 0;
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static const char *name = "Prepare loop for pre-inc. addressing modes";
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INITIALIZE_PASS_BEGIN(PPCLoopPreIncPrep, DEBUG_TYPE, name, false, false)
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INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
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INITIALIZE_PASS_DEPENDENCY(ScalarEvolution)
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INITIALIZE_PASS_END(PPCLoopPreIncPrep, DEBUG_TYPE, name, false, false)
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FunctionPass *llvm::createPPCLoopPreIncPrepPass(PPCTargetMachine &TM) {
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return new PPCLoopPreIncPrep(TM);
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}
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namespace {
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struct SCEVLess : std::binary_function<const SCEV *, const SCEV *, bool>
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{
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SCEVLess(ScalarEvolution *SE) : SE(SE) {}
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bool operator() (const SCEV *X, const SCEV *Y) const {
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const SCEV *Diff = SE->getMinusSCEV(X, Y);
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return cast<SCEVConstant>(Diff)->getValue()->getSExtValue() < 0;
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}
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protected:
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ScalarEvolution *SE;
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};
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}
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static bool IsPtrInBounds(Value *BasePtr) {
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Value *StrippedBasePtr = BasePtr;
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while (BitCastInst *BC = dyn_cast<BitCastInst>(StrippedBasePtr))
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StrippedBasePtr = BC->getOperand(0);
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if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(StrippedBasePtr))
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return GEP->isInBounds();
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return false;
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}
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static Value *GetPointerOperand(Value *MemI) {
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if (LoadInst *LMemI = dyn_cast<LoadInst>(MemI)) {
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return LMemI->getPointerOperand();
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} else if (StoreInst *SMemI = dyn_cast<StoreInst>(MemI)) {
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return SMemI->getPointerOperand();
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} else if (IntrinsicInst *IMemI = dyn_cast<IntrinsicInst>(MemI)) {
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if (IMemI->getIntrinsicID() == Intrinsic::prefetch)
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return IMemI->getArgOperand(0);
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}
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return 0;
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}
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bool PPCLoopPreIncPrep::runOnFunction(Function &F) {
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LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
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SE = &getAnalysis<ScalarEvolution>();
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bool MadeChange = false;
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for (LoopInfo::iterator I = LI->begin(), E = LI->end();
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I != E; ++I) {
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Loop *L = *I;
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MadeChange |= runOnLoop(L);
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}
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return MadeChange;
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}
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bool PPCLoopPreIncPrep::runOnLoop(Loop *L) {
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bool MadeChange = false;
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// Only prep. the inner-most loop
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if (!L->empty())
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return MadeChange;
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BasicBlock *Header = L->getHeader();
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const PPCSubtarget *ST =
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TM ? TM->getSubtargetImpl(*Header->getParent()) : nullptr;
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unsigned HeaderLoopPredCount = 0;
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for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
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PI != PE; ++PI) {
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++HeaderLoopPredCount;
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}
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// Collect buckets of comparable addresses used by loads and stores.
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typedef std::multimap<const SCEV *, Instruction *, SCEVLess> Bucket;
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SmallVector<Bucket, 16> Buckets;
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for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
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I != IE; ++I) {
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for (BasicBlock::iterator J = (*I)->begin(), JE = (*I)->end();
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J != JE; ++J) {
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Value *PtrValue;
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Instruction *MemI;
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if (LoadInst *LMemI = dyn_cast<LoadInst>(J)) {
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MemI = LMemI;
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PtrValue = LMemI->getPointerOperand();
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} else if (StoreInst *SMemI = dyn_cast<StoreInst>(J)) {
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MemI = SMemI;
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PtrValue = SMemI->getPointerOperand();
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} else if (IntrinsicInst *IMemI = dyn_cast<IntrinsicInst>(J)) {
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if (IMemI->getIntrinsicID() == Intrinsic::prefetch) {
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MemI = IMemI;
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PtrValue = IMemI->getArgOperand(0);
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} else continue;
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} else continue;
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unsigned PtrAddrSpace = PtrValue->getType()->getPointerAddressSpace();
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if (PtrAddrSpace)
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continue;
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// There are no update forms for Altivec vector load/stores.
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if (ST && ST->hasAltivec() &&
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PtrValue->getType()->getPointerElementType()->isVectorTy())
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continue;
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if (L->isLoopInvariant(PtrValue))
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continue;
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const SCEV *LSCEV = SE->getSCEV(PtrValue);
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if (!isa<SCEVAddRecExpr>(LSCEV))
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continue;
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bool FoundBucket = false;
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for (unsigned i = 0, e = Buckets.size(); i != e; ++i)
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for (Bucket::iterator K = Buckets[i].begin(), KE = Buckets[i].end();
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K != KE; ++K) {
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const SCEV *Diff = SE->getMinusSCEV(K->first, LSCEV);
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if (isa<SCEVConstant>(Diff)) {
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Buckets[i].insert(std::make_pair(LSCEV, MemI));
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FoundBucket = true;
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break;
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}
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}
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if (!FoundBucket) {
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Buckets.push_back(Bucket(SCEVLess(SE)));
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Buckets[Buckets.size()-1].insert(std::make_pair(LSCEV, MemI));
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}
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}
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}
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if (Buckets.empty() || Buckets.size() > MaxVars)
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return MadeChange;
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BasicBlock *LoopPredecessor = L->getLoopPredecessor();
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// If there is no loop predecessor, or the loop predecessor's terminator
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// returns a value (which might contribute to determining the loop's
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// iteration space), insert a new preheader for the loop.
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if (!LoopPredecessor ||
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!LoopPredecessor->getTerminator()->getType()->isVoidTy())
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LoopPredecessor = InsertPreheaderForLoop(L, this);
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if (!LoopPredecessor)
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return MadeChange;
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SmallSet<BasicBlock *, 16> BBChanged;
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for (unsigned i = 0, e = Buckets.size(); i != e; ++i) {
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// The base address of each bucket is transformed into a phi and the others
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// are rewritten as offsets of that variable.
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const SCEVAddRecExpr *BasePtrSCEV =
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cast<SCEVAddRecExpr>(Buckets[i].begin()->first);
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if (!BasePtrSCEV->isAffine())
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continue;
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Instruction *MemI = Buckets[i].begin()->second;
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Value *BasePtr = GetPointerOperand(MemI);
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assert(BasePtr && "No pointer operand");
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Type *I8PtrTy = Type::getInt8PtrTy(MemI->getParent()->getContext(),
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BasePtr->getType()->getPointerAddressSpace());
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const SCEV *BasePtrStartSCEV = BasePtrSCEV->getStart();
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if (!SE->isLoopInvariant(BasePtrStartSCEV, L))
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continue;
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const SCEVConstant *BasePtrIncSCEV =
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dyn_cast<SCEVConstant>(BasePtrSCEV->getStepRecurrence(*SE));
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if (!BasePtrIncSCEV)
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continue;
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BasePtrStartSCEV = SE->getMinusSCEV(BasePtrStartSCEV, BasePtrIncSCEV);
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if (!isSafeToExpand(BasePtrStartSCEV, *SE))
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continue;
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PHINode *NewPHI = PHINode::Create(I8PtrTy, HeaderLoopPredCount,
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MemI->hasName() ? MemI->getName() + ".phi" : "",
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Header->getFirstNonPHI());
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SCEVExpander SCEVE(*SE, "pistart");
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Value *BasePtrStart = SCEVE.expandCodeFor(BasePtrStartSCEV, I8PtrTy,
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LoopPredecessor->getTerminator());
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// Note that LoopPredecessor might occur in the predecessor list multiple
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// times, and we need to add it the right number of times.
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for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
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PI != PE; ++PI) {
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if (*PI != LoopPredecessor)
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continue;
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NewPHI->addIncoming(BasePtrStart, LoopPredecessor);
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}
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Instruction *InsPoint = Header->getFirstInsertionPt();
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GetElementPtrInst *PtrInc =
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GetElementPtrInst::Create(NewPHI, BasePtrIncSCEV->getValue(),
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MemI->hasName() ? MemI->getName() + ".inc" : "", InsPoint);
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PtrInc->setIsInBounds(IsPtrInBounds(BasePtr));
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for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
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PI != PE; ++PI) {
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if (*PI == LoopPredecessor)
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continue;
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NewPHI->addIncoming(PtrInc, *PI);
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}
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Instruction *NewBasePtr;
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if (PtrInc->getType() != BasePtr->getType())
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NewBasePtr = new BitCastInst(PtrInc, BasePtr->getType(),
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PtrInc->hasName() ? PtrInc->getName() + ".cast" : "", InsPoint);
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else
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NewBasePtr = PtrInc;
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if (Instruction *IDel = dyn_cast<Instruction>(BasePtr))
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BBChanged.insert(IDel->getParent());
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BasePtr->replaceAllUsesWith(NewBasePtr);
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RecursivelyDeleteTriviallyDeadInstructions(BasePtr);
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Value *LastNewPtr = NewBasePtr;
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for (Bucket::iterator I = std::next(Buckets[i].begin()),
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IE = Buckets[i].end(); I != IE; ++I) {
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Value *Ptr = GetPointerOperand(I->second);
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assert(Ptr && "No pointer operand");
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if (Ptr == LastNewPtr)
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continue;
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Instruction *RealNewPtr;
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const SCEVConstant *Diff =
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cast<SCEVConstant>(SE->getMinusSCEV(I->first, BasePtrSCEV));
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if (Diff->isZero()) {
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RealNewPtr = NewBasePtr;
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} else {
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Instruction *PtrIP = dyn_cast<Instruction>(Ptr);
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if (PtrIP && isa<Instruction>(NewBasePtr) &&
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cast<Instruction>(NewBasePtr)->getParent() == PtrIP->getParent())
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PtrIP = 0;
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else if (isa<PHINode>(PtrIP))
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PtrIP = PtrIP->getParent()->getFirstInsertionPt();
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else if (!PtrIP)
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PtrIP = I->second;
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GetElementPtrInst *NewPtr =
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GetElementPtrInst::Create(PtrInc, Diff->getValue(),
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I->second->hasName() ? I->second->getName() + ".off" : "", PtrIP);
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if (!PtrIP)
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NewPtr->insertAfter(cast<Instruction>(PtrInc));
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NewPtr->setIsInBounds(IsPtrInBounds(Ptr));
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RealNewPtr = NewPtr;
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}
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if (Instruction *IDel = dyn_cast<Instruction>(Ptr))
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BBChanged.insert(IDel->getParent());
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Instruction *ReplNewPtr;
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if (Ptr->getType() != RealNewPtr->getType()) {
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ReplNewPtr = new BitCastInst(RealNewPtr, Ptr->getType(),
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Ptr->hasName() ? Ptr->getName() + ".cast" : "");
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ReplNewPtr->insertAfter(RealNewPtr);
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} else
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ReplNewPtr = RealNewPtr;
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Ptr->replaceAllUsesWith(ReplNewPtr);
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RecursivelyDeleteTriviallyDeadInstructions(Ptr);
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LastNewPtr = RealNewPtr;
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}
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MadeChange = true;
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}
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for (Loop::block_iterator I = L->block_begin(), IE = L->block_end();
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I != IE; ++I) {
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if (BBChanged.count(*I))
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DeleteDeadPHIs(*I);
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}
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return MadeChange;
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}
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