[SelectionDAG] Remove PeekThroughFreeze (NFC) #148022
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Now that SelectionDAG already peeks through freezes, this is not needed anymore.
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@llvm/pr-subscribers-llvm-selectiondag Author: AZero13 (AZero13) ChangesNow that SelectionDAG already peeks through freezes, this is not needed anymore. Full diff: https://github.com/llvm/llvm-project/pull/148022.diff 1 Files Affected:
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9ffdda28f7899..6767606f0719a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4067,18 +4067,12 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
unsigned BitWidth = VT.getScalarSizeInBits();
SDLoc DL(N);
- auto PeekThroughFreeze = [](SDValue N) {
- if (N->getOpcode() == ISD::FREEZE && N.hasOneUse())
- return N->getOperand(0);
- return N;
- };
-
if (SDValue V = foldSubCtlzNot<EmptyMatchContext>(N, DAG))
return V;
// fold (sub x, x) -> 0
// FIXME: Refactor this and xor and other similar operations together.
- if (PeekThroughFreeze(N0) == PeekThroughFreeze(N1))
+ if (N0 == N1)
return tryFoldToZero(DL, TLI, VT, DAG, LegalOperations);
// fold (sub c1, c2) -> c3
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arsenm
approved these changes
Jul 10, 2025
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Here are two tests where I believe this code triggers https://godbolt.org/z/sY79E6d5o https://godbolt.org/z/raosvoWsT |
you know i swapped sub with xor and suddenly the div made it |
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Disregard this. Let's go back to #147821 |
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Now that SelectionDAG already peeks through freezes, this is not needed anymore.