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[InstCombine] collectBitParts - use APInt directly to check for out of range bit shifts. NFCI.

This commit is contained in:
Simon Pilgrim 2020-10-01 12:49:59 +01:00
parent ef4e971e5e
commit bc730b5e43
1 changed files with 7 additions and 7 deletions
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14
llvm/lib/Transforms/Utils/Local.cpp
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@ -2872,10 +2872,10 @@ collectBitParts(Value *V, bool MatchBSwaps, bool MatchBitReversals,
// If this is a logical shift by a constant, recurse then shift the result.
if (I->isLogicalShift() && isa<ConstantInt>(I->getOperand(1))) {
unsigned BitShift =
cast<ConstantInt>(I->getOperand(1))->getLimitedValue(~0U);
const APInt &BitShift = cast<ConstantInt>(I->getOperand(1))->getValue();
// Ensure the shift amount is defined.
if (BitShift > BitWidth)
if (BitShift.uge(BitWidth))
return Result;
const auto &Res = collectBitParts(I->getOperand(0), MatchBSwaps,
@ -2887,11 +2887,11 @@ collectBitParts(Value *V, bool MatchBSwaps, bool MatchBitReversals,
// Perform the "shift" on BitProvenance.
auto &P = Result->Provenance;
if (I->getOpcode() == Instruction::Shl) {
P.erase(std::prev(P.end(), BitShift), P.end());
P.insert(P.begin(), BitShift, BitPart::Unset);
P.erase(std::prev(P.end(), BitShift.getZExtValue()), P.end());
P.insert(P.begin(), BitShift.getZExtValue(), BitPart::Unset);
} else {
P.erase(P.begin(), std::next(P.begin(), BitShift));
P.insert(P.end(), BitShift, BitPart::Unset);
P.erase(P.begin(), std::next(P.begin(), BitShift.getZExtValue()));
P.insert(P.end(), BitShift.getZExtValue(), BitPart::Unset);
}
return Result;