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[X86] Enforce strict pre-legalization to combine in scalarizeExtEltFP #117681
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@llvm/pr-subscribers-backend-x86 Author: None (abhishek-kaushik22) ChangesUse a Full diff: https://github.com/llvm/llvm-project/pull/117681.diff 1 Files Affected:
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index e4533570f75086..365ae660ea91e8 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -45842,7 +45842,8 @@ static SDValue combineExtractWithShuffle(SDNode *N, SelectionDAG &DAG,
/// Extracting a scalar FP value from vector element 0 is free, so extract each
/// operand first, then perform the math as a scalar op.
static SDValue scalarizeExtEltFP(SDNode *ExtElt, SelectionDAG &DAG,
- const X86Subtarget &Subtarget) {
+ const X86Subtarget &Subtarget,
+ TargetLowering::DAGCombinerInfo &DCI) {
assert(ExtElt->getOpcode() == ISD::EXTRACT_VECTOR_ELT && "Expected extract");
SDValue Vec = ExtElt->getOperand(0);
SDValue Index = ExtElt->getOperand(1);
@@ -45877,10 +45878,10 @@ static SDValue scalarizeExtEltFP(SDNode *ExtElt, SelectionDAG &DAG,
// Vector FP selects don't fit the pattern of FP math ops (because the
// condition has a different type and we have to change the opcode), so deal
// with those here.
- // FIXME: This is restricted to pre type legalization by ensuring the setcc
- // has i1 elements. If we loosen this we need to convert vector bool to a
- // scalar bool.
- if (Vec.getOpcode() == ISD::VSELECT &&
+ // FIXME: This is restricted to pre type legalization. If we loosen this we
+ // need to convert vector bool to a scalar bool.
+ if (DCI.getDAGCombineLevel() < llvm::AfterLegalizeTypes &&
+ Vec.getOpcode() == ISD::VSELECT &&
Vec.getOperand(0).getOpcode() == ISD::SETCC &&
Vec.getOperand(0).getValueType().getScalarType() == MVT::i1 &&
Vec.getOperand(0).getOperand(0).getValueType() == VecVT) {
@@ -46242,7 +46243,7 @@ static SDValue combineExtractVectorElt(SDNode *N, SelectionDAG &DAG,
if (SDValue V = combineArithReduction(N, DAG, Subtarget))
return V;
- if (SDValue V = scalarizeExtEltFP(N, DAG, Subtarget))
+ if (SDValue V = scalarizeExtEltFP(N, DAG, Subtarget, DCI))
return V;
if (CIdx)
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phoebewang
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This looks better than #117682
Please add the example as regression test.
phoebewang
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LGTM in general.
RKSimon
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LGTM - cheers
Use a
DCIobject to actually check the DAG combine level instead of using the typei1because this assumption fails on AVX512 where we have types likev8i1after legalization.Closes #117684