mirror of
https://github.com/c64scene-ar/llvm-6502.git
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into their new header subdirectory: include/llvm/IR. This matches the directory structure of lib, and begins to correct a long standing point of file layout clutter in LLVM. There are still more header files to move here, but I wanted to handle them in separate commits to make tracking what files make sense at each layer easier. The only really questionable files here are the target intrinsic tablegen files. But that's a battle I'd rather not fight today. I've updated both CMake and Makefile build systems (I think, and my tests think, but I may have missed something). I've also re-sorted the includes throughout the project. I'll be committing updates to Clang, DragonEgg, and Polly momentarily. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
175 lines
5.2 KiB
C++
175 lines
5.2 KiB
C++
//===- LowerExpectIntrinsic.cpp - Lower expect intrinsic ------------------===//
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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 lowers the 'expect' intrinsic to LLVM metadata.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "lower-expect-intrinsic"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/Intrinsics.h"
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#include "llvm/IR/LLVMContext.h"
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#include "llvm/IR/MDBuilder.h"
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#include "llvm/IR/Metadata.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 <vector>
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using namespace llvm;
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STATISTIC(IfHandled, "Number of 'expect' intrinsic intructions handled");
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static cl::opt<uint32_t>
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LikelyBranchWeight("likely-branch-weight", cl::Hidden, cl::init(64),
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cl::desc("Weight of the branch likely to be taken (default = 64)"));
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static cl::opt<uint32_t>
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UnlikelyBranchWeight("unlikely-branch-weight", cl::Hidden, cl::init(4),
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cl::desc("Weight of the branch unlikely to be taken (default = 4)"));
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namespace {
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class LowerExpectIntrinsic : public FunctionPass {
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bool HandleSwitchExpect(SwitchInst *SI);
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bool HandleIfExpect(BranchInst *BI);
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public:
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static char ID;
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LowerExpectIntrinsic() : FunctionPass(ID) {
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initializeLowerExpectIntrinsicPass(*PassRegistry::getPassRegistry());
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}
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bool runOnFunction(Function &F);
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};
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}
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bool LowerExpectIntrinsic::HandleSwitchExpect(SwitchInst *SI) {
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CallInst *CI = dyn_cast<CallInst>(SI->getCondition());
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if (!CI)
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return false;
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Function *Fn = CI->getCalledFunction();
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if (!Fn || Fn->getIntrinsicID() != Intrinsic::expect)
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return false;
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Value *ArgValue = CI->getArgOperand(0);
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ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(CI->getArgOperand(1));
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if (!ExpectedValue)
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return false;
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SwitchInst::CaseIt Case = SI->findCaseValue(ExpectedValue);
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unsigned n = SI->getNumCases(); // +1 for default case.
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std::vector<uint32_t> Weights(n + 1);
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Weights[0] = Case == SI->case_default() ? LikelyBranchWeight
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: UnlikelyBranchWeight;
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for (unsigned i = 0; i != n; ++i)
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Weights[i + 1] = i == Case.getCaseIndex() ? LikelyBranchWeight
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: UnlikelyBranchWeight;
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SI->setMetadata(LLVMContext::MD_prof,
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MDBuilder(CI->getContext()).createBranchWeights(Weights));
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SI->setCondition(ArgValue);
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return true;
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}
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bool LowerExpectIntrinsic::HandleIfExpect(BranchInst *BI) {
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if (BI->isUnconditional())
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return false;
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// Handle non-optimized IR code like:
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// %expval = call i64 @llvm.expect.i64.i64(i64 %conv1, i64 1)
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// %tobool = icmp ne i64 %expval, 0
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// br i1 %tobool, label %if.then, label %if.end
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ICmpInst *CmpI = dyn_cast<ICmpInst>(BI->getCondition());
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if (!CmpI || CmpI->getPredicate() != CmpInst::ICMP_NE)
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return false;
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CallInst *CI = dyn_cast<CallInst>(CmpI->getOperand(0));
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if (!CI)
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return false;
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Function *Fn = CI->getCalledFunction();
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if (!Fn || Fn->getIntrinsicID() != Intrinsic::expect)
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return false;
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Value *ArgValue = CI->getArgOperand(0);
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ConstantInt *ExpectedValue = dyn_cast<ConstantInt>(CI->getArgOperand(1));
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if (!ExpectedValue)
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return false;
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MDBuilder MDB(CI->getContext());
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MDNode *Node;
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// If expect value is equal to 1 it means that we are more likely to take
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// branch 0, in other case more likely is branch 1.
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if (ExpectedValue->isOne())
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Node = MDB.createBranchWeights(LikelyBranchWeight, UnlikelyBranchWeight);
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else
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Node = MDB.createBranchWeights(UnlikelyBranchWeight, LikelyBranchWeight);
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BI->setMetadata(LLVMContext::MD_prof, Node);
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CmpI->setOperand(0, ArgValue);
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return true;
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}
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bool LowerExpectIntrinsic::runOnFunction(Function &F) {
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for (Function::iterator I = F.begin(), E = F.end(); I != E;) {
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BasicBlock *BB = I++;
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// Create "block_weights" metadata.
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if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator())) {
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if (HandleIfExpect(BI))
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IfHandled++;
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} else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
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if (HandleSwitchExpect(SI))
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IfHandled++;
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}
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// remove llvm.expect intrinsics.
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for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
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BI != BE; ) {
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CallInst *CI = dyn_cast<CallInst>(BI++);
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if (!CI)
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continue;
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Function *Fn = CI->getCalledFunction();
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if (Fn && Fn->getIntrinsicID() == Intrinsic::expect) {
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Value *Exp = CI->getArgOperand(0);
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CI->replaceAllUsesWith(Exp);
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CI->eraseFromParent();
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}
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}
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}
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return false;
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}
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char LowerExpectIntrinsic::ID = 0;
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INITIALIZE_PASS(LowerExpectIntrinsic, "lower-expect", "Lower 'expect' "
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"Intrinsics", false, false)
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FunctionPass *llvm::createLowerExpectIntrinsicPass() {
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return new LowerExpectIntrinsic();
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}
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