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[nfc][InstCombine]Find PHI incoming block by operand number (#93249)

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Mingming Liu 2024-05-24 14:19:02 -07:00 committed by GitHub
parent 8f21909c2f
commit 56c5ca8f66
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1 changed files with 13 additions and 20 deletions
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33
llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
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@ -5000,31 +5000,24 @@ bool InstCombinerImpl::run() {
BasicBlock *UserParent = nullptr;
unsigned NumUsers = 0;
for (auto *U : I->users()) {
if (U->isDroppable())
for (Use &U : I->uses()) {
User *User = U.getUser();
if (User->isDroppable())
continue;
if (NumUsers > MaxSinkNumUsers)
return std::nullopt;
Instruction *UserInst = cast<Instruction>(U);
Instruction *UserInst = cast<Instruction>(User);
// Special handling for Phi nodes - get the block the use occurs in.
if (PHINode *PN = dyn_cast<PHINode>(UserInst)) {
for (unsigned i = 0; i < PN->getNumIncomingValues(); i++) {
if (PN->getIncomingValue(i) == I) {
// Bail out if we have uses in different blocks. We don't do any
// sophisticated analysis (i.e finding NearestCommonDominator of
// these use blocks).
if (UserParent && UserParent != PN->getIncomingBlock(i))
return std::nullopt;
UserParent = PN->getIncomingBlock(i);
}
}
assert(UserParent && "expected to find user block!");
} else {
if (UserParent && UserParent != UserInst->getParent())
return std::nullopt;
UserParent = UserInst->getParent();
}
BasicBlock *UserBB = UserInst->getParent();
if (PHINode *PN = dyn_cast<PHINode>(UserInst))
UserBB = PN->getIncomingBlock(U);
// Bail out if we have uses in different blocks. We don't do any
// sophisticated analysis (i.e finding NearestCommonDominator of these
// use blocks).
if (UserParent && UserParent != UserBB)
return std::nullopt;
UserParent = UserBB;
// Make sure these checks are done only once, naturally we do the checks
// the first time we get the userparent, this will save compile time.