60 lines
2 KiB
C++
60 lines
2 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/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/Transforms/Scalar.h"
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using namespace llvm;
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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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// Traverse through the users of WCDecl.
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// This is presumably cheaper than traversing all instructions in the
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// function.
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for (auto *U : WCDecl->users())
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if (auto *CI = dyn_cast<CallInst>(U))
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if (CI->getFunction() == &F)
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ToLower.push_back(CI);
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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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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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