GuardUtils.cpp
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//===-- GuardUtils.cpp - Utils for work with guards -------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// Utils that are used to perform analyzes related to guards and their
// conditions.
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/GuardUtils.h"
#include "llvm/IR/PatternMatch.h"
using namespace llvm;
using namespace llvm::PatternMatch;
bool llvm::isGuard(const User *U) {
return match(U, m_Intrinsic<Intrinsic::experimental_guard>());
}
bool llvm::isWidenableBranch(const User *U) {
Value *Condition, *WidenableCondition;
BasicBlock *GuardedBB, *DeoptBB;
return parseWidenableBranch(U, Condition, WidenableCondition, GuardedBB,
DeoptBB);
}
bool llvm::isGuardAsWidenableBranch(const User *U) {
Value *Condition, *WidenableCondition;
BasicBlock *GuardedBB, *DeoptBB;
if (!parseWidenableBranch(U, Condition, WidenableCondition, GuardedBB,
DeoptBB))
return false;
for (auto &Insn : *DeoptBB) {
if (match(&Insn, m_Intrinsic<Intrinsic::experimental_deoptimize>()))
return true;
if (Insn.mayHaveSideEffects())
return false;
}
return false;
}
bool llvm::parseWidenableBranch(const User *U, Value *&Condition,
Value *&WidenableCondition,
BasicBlock *&IfTrueBB, BasicBlock *&IfFalseBB) {
Use *C, *WC;
if (parseWidenableBranch(const_cast<User*>(U), C, WC, IfTrueBB, IfFalseBB)) {
if (C)
Condition = C->get();
else
Condition = ConstantInt::getTrue(IfTrueBB->getContext());
WidenableCondition = WC->get();
return true;
}
return false;
}
bool llvm::parseWidenableBranch(User *U, Use *&C,Use *&WC,
BasicBlock *&IfTrueBB, BasicBlock *&IfFalseBB) {
auto *BI = dyn_cast<BranchInst>(U);
if (!BI || !BI->isConditional())
return false;
auto *Cond = BI->getCondition();
if (!Cond->hasOneUse())
return false;
IfTrueBB = BI->getSuccessor(0);
IfFalseBB = BI->getSuccessor(1);
if (match(Cond, m_Intrinsic<Intrinsic::experimental_widenable_condition>())) {
WC = &BI->getOperandUse(0);
C = nullptr;
return true;
}
// Check for two cases:
// 1) br (i1 (and A, WC())), label %IfTrue, label %IfFalse
// 2) br (i1 (and WC(), B)), label %IfTrue, label %IfFalse
// We do not check for more generalized and trees as we should canonicalize
// to the form above in instcombine. (TODO)
Value *A, *B;
if (!match(Cond, m_And(m_Value(A), m_Value(B))))
return false;
auto *And = dyn_cast<Instruction>(Cond);
if (!And)
// Could be a constexpr
return false;
if (match(A, m_Intrinsic<Intrinsic::experimental_widenable_condition>()) &&
A->hasOneUse()) {
WC = &And->getOperandUse(0);
C = &And->getOperandUse(1);
return true;
}
if (match(B, m_Intrinsic<Intrinsic::experimental_widenable_condition>()) &&
B->hasOneUse()) {
WC = &And->getOperandUse(1);
C = &And->getOperandUse(0);
return true;
}
return false;
}