diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Utils/SimplifyCFG.cpp | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp index 64e75548e0f..877e55928d4 100644 --- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp @@ -1428,6 +1428,25 @@ static bool canSinkInstructions( if (I0->getOperand(OI)->getType()->isTokenTy()) // Don't touch any operand of token type. return false; + + // Because SROA can't handle speculating stores of selects, try not + // to sink loads or stores of allocas when we'd have to create a PHI for + // the address operand. Also, because it is likely that loads or stores + // of allocas will disappear when Mem2Reg/SROA is run, don't sink them. + // This can cause code churn which can have unintended consequences down + // the line - see https://llvm.org/bugs/show_bug.cgi?id=30244. + // FIXME: This is a workaround for a deficiency in SROA - see + // https://llvm.org/bugs/show_bug.cgi?id=30188 + if (OI == 1 && isa<StoreInst>(I0) && + any_of(Insts, [](const Instruction *I) { + return isa<AllocaInst>(I->getOperand(1)); + })) + return false; + if (OI == 0 && isa<LoadInst>(I0) && any_of(Insts, [](const Instruction *I) { + return isa<AllocaInst>(I->getOperand(0)); + })) + return false; + auto SameAsI0 = [&I0, OI](const Instruction *I) { assert(I->getNumOperands() == I0->getNumOperands()); return I->getOperand(OI) == I0->getOperand(OI); @@ -1441,21 +1460,6 @@ static bool canSinkInstructions( // FIXME: if the call was *already* indirect, we should do this. return false; } - // Because SROA can't handle speculating stores of selects, try not - // to sink loads or stores of allocas when we'd have to create a PHI for - // the address operand. - // FIXME: This is a workaround for a deficiency in SROA - see - // https://llvm.org/bugs/show_bug.cgi?id=30188 - if (OI == 1 && isa<StoreInst>(I0) && - any_of(Insts, [](const Instruction *I) { - return isa<AllocaInst>(I->getOperand(1)); - })) - return false; - if (OI == 0 && isa<LoadInst>(I0) && - any_of(Insts, [](const Instruction *I) { - return isa<AllocaInst>(I->getOperand(0)); - })) - return false; for (auto *I : Insts) PHIOperands[I].push_back(I->getOperand(OI)); } |
