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[X86] combineConcatVectorOps - IsConcatFree - detect splats that comes from a common load/broadcastload (#174986)

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Allows us to handle freely concatable cases after a broadcast load has
become shared by different vector width uses by peeking through
bitcasts/extract_subvector nodes
This commit is contained in:
Simon Pilgrim 2026-01-08 15:39:57 +00:00 committed by GitHub
parent da560b6579
commit c8674f65fe
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2 changed files with 32 additions and 17 deletions
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8
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -59234,7 +59234,13 @@ static SDValue combineConcatVectorOps(const SDLoc &DL, MVT VT,
if (all_of(SubOps, [&](SDValue SubOp) {
return SubOp0 == SubOp.getOperand(Op);
})) {
if (isa<LoadSDNode>(peekThroughBitcasts(SubOp0)))
SDValue Src = SubOp0;
while (Src.getOpcode() == ISD::BITCAST ||
Src.getOpcode() == ISD::EXTRACT_SUBVECTOR)
Src = Src.getOperand(0);
if (ISD::isNormalLoad(Src.getNode()) ||
Src.getOpcode() == X86ISD::VBROADCAST_LOAD ||
Src.getOpcode() == X86ISD::SUBV_BROADCAST_LOAD)
return true;
}
SmallVector<SDValue> Subs;

41
llvm/test/CodeGen/X86/combine-fma-concat.ll
View File

@ -279,32 +279,41 @@ define <8 x double> @concat_fma_fmsub_v8f64_v4f64_constant_repeatedop_commute(<4
ret <8 x double> %r
}
; FIXME: FMA can't be concatenated until after max intrinsics have lowered, but then the v4f32 broadcasted constant is hidden behind an EXTRACT_SUBVECTOR
; FMA can't be concatenated until after max intrinsics have lowered, but then the v4f32 broadcasted constant is hidden behind an EXTRACT_SUBVECTOR
define <8 x float> @concat_fma_v8f32_v4f32_late_concat(<4 x float> %x, <4 x float> %y, <8 x float> %z) {
; FMA4-LABEL: concat_fma_v8f32_v4f32_late_concat:
; FMA4: # %bb.0:
; FMA4-NEXT: vmovaps {{.*#+}} ymm3 = [2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0]
; FMA4-NEXT: vfmaddps {{.*#+}} xmm0 = (xmm0 * xmm0) + xmm3
; FMA4-NEXT: vfmaddps {{.*#+}} xmm1 = (xmm1 * xmm1) + xmm3
; FMA4-NEXT: vmaxps %ymm3, %ymm2, %ymm2
; FMA4-NEXT: vbroadcastf128 {{.*#+}} ymm3 = [2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0]
; FMA4-NEXT: # ymm3 = mem[0,1,0,1]
; FMA4-NEXT: # kill: def $xmm0 killed $xmm0 def $ymm0
; FMA4-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm0
; FMA4-NEXT: vmaxps {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm2, %ymm2
; FMA4-NEXT: vfmaddps {{.*#+}} ymm0 = (ymm0 * ymm0) + ymm3
; FMA4-NEXT: vmaxps %ymm3, %ymm0, %ymm0
; FMA4-NEXT: vaddps %ymm2, %ymm0, %ymm0
; FMA4-NEXT: retq
;
; FMA3-LABEL: concat_fma_v8f32_v4f32_late_concat:
; FMA3: # %bb.0:
; FMA3-NEXT: # kill: def $xmm0 killed $xmm0 def $ymm0
; FMA3-NEXT: vbroadcastss {{.*#+}} ymm3 = [2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0]
; FMA3-NEXT: vfmadd213ps {{.*#+}} xmm0 = (xmm0 * xmm0) + xmm3
; FMA3-NEXT: vfmadd213ps {{.*#+}} xmm1 = (xmm1 * xmm1) + xmm3
; FMA3-NEXT: vmaxps %ymm3, %ymm2, %ymm2
; FMA3-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm0
; FMA3-NEXT: vmaxps %ymm3, %ymm0, %ymm0
; FMA3-NEXT: vaddps %ymm2, %ymm0, %ymm0
; FMA3-NEXT: retq
; AVX2-LABEL: concat_fma_v8f32_v4f32_late_concat:
; AVX2: # %bb.0:
; AVX2-NEXT: # kill: def $xmm0 killed $xmm0 def $ymm0
; AVX2-NEXT: vbroadcastss {{.*#+}} ymm3 = [2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0]
; AVX2-NEXT: vmaxps %ymm3, %ymm2, %ymm2
; AVX2-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm0
; AVX2-NEXT: vfmadd213ps {{.*#+}} ymm0 = (ymm0 * ymm0) + ymm3
; AVX2-NEXT: vmaxps %ymm3, %ymm0, %ymm0
; AVX2-NEXT: vaddps %ymm2, %ymm0, %ymm0
; AVX2-NEXT: retq
;
; AVX512-LABEL: concat_fma_v8f32_v4f32_late_concat:
; AVX512: # %bb.0:
; AVX512-NEXT: vbroadcastss {{.*#+}} ymm3 = [2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0,2.0E+0]
; AVX512-NEXT: # kill: def $xmm0 killed $xmm0 def $ymm0
; AVX512-NEXT: vmaxps %ymm3, %ymm2, %ymm2
; AVX512-NEXT: vinsertf128 $1, %xmm1, %ymm0, %ymm0
; AVX512-NEXT: vfmadd213ps {{.*#+}} ymm0 = (ymm0 * ymm0) + ymm3
; AVX512-NEXT: vmaxps %ymm3, %ymm0, %ymm0
; AVX512-NEXT: vaddps %ymm2, %ymm0, %ymm0
; AVX512-NEXT: retq
%xx = call <4 x float> @llvm.fma.v4f32(<4 x float> %x, <4 x float> %x, <4 x float> splat (float 2.000000e+00))
%yy = call <4 x float> @llvm.fma.v4f32(<4 x float> %y, <4 x float> %y, <4 x float> splat (float 2.000000e+00))
%lo = call <4 x float> @llvm.x86.sse.max.ps(<4 x float> %xx, <4 x float> splat (float 2.000000e+00))