d76a1639e0
Use splitBasicBlock and avoid directly dealing with the specific of how to trim the existing terminators. We just need to deal with unconditional branch to return.
83 lines
2.7 KiB
C++
83 lines
2.7 KiB
C++
//===- Utils.cpp - llvm-reduce utility functions --------------------------===//
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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 file contains some utility functions supporting llvm-reduce.
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//
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//===----------------------------------------------------------------------===//
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#include "Utils.h"
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#include "llvm/IR/Constants.h"
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#include "llvm/IR/GlobalAlias.h"
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#include "llvm/IR/GlobalIFunc.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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using namespace llvm;
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extern cl::OptionCategory LLVMReduceOptions;
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cl::opt<bool> llvm::Verbose("verbose",
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cl::desc("Print extra debugging information"),
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cl::init(false), cl::cat(LLVMReduceOptions));
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Value *llvm::getDefaultValue(Type *T) {
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if (T->isVoidTy())
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return PoisonValue::get(T);
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if (auto *TET = dyn_cast<TargetExtType>(T)) {
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if (TET->hasProperty(TargetExtType::HasZeroInit))
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return ConstantTargetNone::get(TET);
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return PoisonValue::get(TET);
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}
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return Constant::getNullValue(T);
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}
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bool llvm::hasAliasUse(Function &F) {
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return any_of(F.users(), [](User *U) {
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return isa<GlobalAlias>(U) || isa<GlobalIFunc>(U);
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});
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}
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void llvm::simpleSimplifyCFG(Function &F, ArrayRef<BasicBlock *> BBs,
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bool FoldBlockIntoPredecessor) {
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for (BasicBlock *BB : BBs) {
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ConstantFoldTerminator(BB);
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if (FoldBlockIntoPredecessor)
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MergeBlockIntoPredecessor(BB);
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}
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// Remove unreachable blocks
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//
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// removeUnreachableBlocks can't be used here, it will turn various undefined
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// behavior into unreachables, but llvm-reduce was the thing that generated
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// the undefined behavior, and we don't want it to kill the entire program.
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SmallPtrSet<BasicBlock *, 16> Visited(llvm::from_range,
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depth_first(&F.getEntryBlock()));
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SmallVector<BasicBlock *, 16> Unreachable;
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for (BasicBlock &BB : F) {
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if (!Visited.count(&BB))
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Unreachable.push_back(&BB);
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}
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// The dead BB's may be in a dead cycle or otherwise have references to each
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// other. Because of this, we have to drop all references first, then delete
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// them all at once.
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for (BasicBlock *BB : Unreachable) {
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for (BasicBlock *Successor : successors(&*BB))
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if (Visited.count(Successor))
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Successor->removePredecessor(&*BB, /*KeepOneInputPHIs=*/true);
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BB->dropAllReferences();
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}
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for (BasicBlock *BB : Unreachable)
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BB->eraseFromParent();
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}
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