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[X86] Combine bitcast(v1Ty insert_vector_elt(X, Y, 0)) to Y #130475

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Merged
merged 1 commit into from
Mar 9, 2025
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[X86] Combine bitcast(v1Ty insert_vector_elt(X, Y, 0)) to Y #130475

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5 changes: 5 additions & 0 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -45486,6 +45486,11 @@ static SDValue combineBitcast(SDNode *N, SelectionDAG &DAG,
if (SDValue V = combineCastedMaskArithmetic(N, DAG, DCI, Subtarget))
return V;

// bitcast(v1Ty insert_vector_elt(X, Y, 0)) --> Y
if (N0.getOpcode() == ISD::INSERT_VECTOR_ELT && SrcVT.getScalarType() == VT &&
SrcVT.getVectorNumElements() == 1)
return N0.getOperand(1);

// Convert a bitcasted integer logic operation that has one bitcasted
// floating-point operand into a floating-point logic operation. This may
// create a load of a constant, but that is cheaper than materializing the
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15 changes: 15 additions & 0 deletions llvm/test/CodeGen/X86/apx/cf.ll
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Expand Up @@ -124,3 +124,18 @@ entry:
call void @llvm.masked.store.v4i64.p0(<4 x i64> %0, ptr %p, i32 8, <4 x i1> %cond2)
ret void
}

define void @single_cmp(i32 %a, i32 %b, ptr %c, ptr %d) #2 {
; CHECK-LABEL: single_cmp:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: cmpl %esi, %edi
; CHECK-NEXT: cfcmovnew (%rdx), %ax
; CHECK-NEXT: cfcmovnew %ax, (%rcx)
; CHECK-NEXT: retq
entry:
%0 = icmp ne i32 %a, %b
%1 = insertelement <1 x i1> poison, i1 %0, i64 0
%2 = tail call <1 x i16> @llvm.masked.load.v1i16.p0(ptr %c, i32 2, <1 x i1> %1, <1 x i16> poison)
tail call void @llvm.masked.store.v1i16.p0(<1 x i16> %2, ptr %d, i32 2, <1 x i1> %1)
ret void
}