86 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			86 lines
		
	
	
		
			2.7 KiB
		
	
	
	
		
			C++
		
	
	
	
//===- LowerWidenableCondition.cpp - Lower the guard intrinsic ---------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass lowers the llvm.widenable.condition intrinsic to default value
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// which is i1 true.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Scalar/LowerWidenableCondition.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/Analysis/GuardUtils.h"
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#include "llvm/IR/BasicBlock.h"
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#include "llvm/IR/Function.h"
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#include "llvm/IR/InstIterator.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/Module.h"
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#include "llvm/IR/PatternMatch.h"
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#include "llvm/Pass.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils/GuardUtils.h"
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using namespace llvm;
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namespace {
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struct LowerWidenableConditionLegacyPass : public FunctionPass {
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  static char ID;
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  LowerWidenableConditionLegacyPass() : FunctionPass(ID) {
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    initializeLowerWidenableConditionLegacyPassPass(
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        *PassRegistry::getPassRegistry());
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  }
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  bool runOnFunction(Function &F) override;
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};
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}
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static bool lowerWidenableCondition(Function &F) {
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  // Check if we can cheaply rule out the possibility of not having any work to
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  // do.
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  auto *WCDecl = F.getParent()->getFunction(
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      Intrinsic::getName(Intrinsic::experimental_widenable_condition));
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  if (!WCDecl || WCDecl->use_empty())
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    return false;
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  using namespace llvm::PatternMatch;
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  SmallVector<CallInst *, 8> ToLower;
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  for (auto &I : instructions(F))
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    if (match(&I, m_Intrinsic<Intrinsic::experimental_widenable_condition>()))
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      ToLower.push_back(cast<CallInst>(&I));
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  if (ToLower.empty())
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    return false;
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  for (auto *CI : ToLower) {
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    CI->replaceAllUsesWith(ConstantInt::getTrue(CI->getContext()));
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    CI->eraseFromParent();
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  }
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  return true;
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}
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bool LowerWidenableConditionLegacyPass::runOnFunction(Function &F) {
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  return lowerWidenableCondition(F);
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}
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char LowerWidenableConditionLegacyPass::ID = 0;
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INITIALIZE_PASS(LowerWidenableConditionLegacyPass, "lower-widenable-condition",
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                "Lower the widenable condition to default true value", false,
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                false)
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Pass *llvm::createLowerWidenableConditionPass() {
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  return new LowerWidenableConditionLegacyPass();
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}
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PreservedAnalyses LowerWidenableConditionPass::run(Function &F,
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                                               FunctionAnalysisManager &AM) {
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  if (lowerWidenableCondition(F))
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    return PreservedAnalyses::none();
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  return PreservedAnalyses::all();
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}
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