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[NFC][Sink] Change runtime checks to asserts #137354

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Merged
merged 3 commits into from
Apr 25, 2025
Merged

[NFC][Sink] Change runtime checks to asserts #137354

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d6914fb
Change dynamic checks to asserts
LU-JOHN Apr 25, 2025
8f6fed5
Use one assert
LU-JOHN Apr 25, 2025
db61bc1
Move assert before final use of SuccToSinkTo
LU-JOHN Apr 25, 2025
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16 changes: 9 additions & 7 deletions llvm/lib/Transforms/Scalar/Sink.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -82,10 +82,11 @@ static bool IsAcceptableTarget(Instruction *Inst, BasicBlock *SuccToSinkTo,
!Inst->hasMetadata(LLVMContext::MD_invariant_load))
return false;

// We don't want to sink across a critical edge if we don't dominate the
// successor. We could be introducing calculations to new code paths.
if (!DT.dominates(Inst->getParent(), SuccToSinkTo))
return false;
// The current location of Inst dominates all uses, thus it must dominate
// SuccToSinkTo, which is on the IDom chain between the nearest common
// dominator to all uses and the current location.
assert(DT.dominates(Inst->getParent(), SuccToSinkTo) &&
"SuccToSinkTo must be dominated by current Inst location!");

// Don't sink instructions into a loop.
Loop *succ = LI.getLoopFor(SuccToSinkTo);
Expand Down Expand Up @@ -144,9 +145,10 @@ static bool SinkInstruction(Instruction *Inst,
SuccToSinkTo = DT.findNearestCommonDominator(SuccToSinkTo, UseBlock);
else
SuccToSinkTo = UseBlock;
// The current basic block needs to dominate the candidate.
if (!DT.dominates(BB, SuccToSinkTo))
return false;
// The current basic block dominates all uses, thus it must dominate
// SuccToSinkTo, the nearest common dominator of all uses.
assert(DT.dominates(BB, SuccToSinkTo) &&
"SuccToSinkTo must be dominated by current basic block!");
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@nikic nikic Apr 25, 2025

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I think it would be better to replace the two asserts with a single one at the end of this function.

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@LU-JOHN LU-JOHN Apr 25, 2025

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I've replaced the two asserts with one assert, but I've put the assert at the beginning of the function since it is already true at that point.

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@nikic nikic Apr 25, 2025

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The reason why I suggest to put it at the end is that SuccToSinkTo is changed in the function. So we are asserting that the property still holds after these adjustments.

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@LU-JOHN LU-JOHN Apr 25, 2025

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Moved assert to when SuccToSinkTo is used to sink instruction.

}

if (SuccToSinkTo) {
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