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[release_36] Cherry-pick r231601.
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Original commit message:
[X86][AVX] Fix wrong lowering of VPERM2X128 nodes

There were cases where the backend computed a wrong permute mask for a VPERM2X128 node.

Example:
\code
define <8 x float> @foo(<8 x float> %a, <8 x float> %b) {
  %shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 undef, i32 undef, i32 6, i32 7>
  ret <8 x float> %shuffle
}
\code end

Before this patch, llc (with -mattr=+avx) emitted the following vperm2f128:
  vperm2f128 $0, %ymm0, %ymm0, %ymm0  # ymm0 = ymm0[0,1,0,1]

With this patch, llc emits a vperm2f128 with a correct permute mask:
  vperm2f128 $17, %ymm0, %ymm0, %ymm0  # ymm0 = ymm0[2,3,2,3]

Differential Revision: http://reviews.llvm.org/D8119

llvm-svn: 232803
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Andrea Di Biagio authored and Andrea Di Biagio committed Mar 20, 2015
1 parent 32326a2 commit df6c515
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Showing 3 changed files with 86 additions and 9 deletions.
10 changes: 9 additions & 1 deletion llvm/lib/Target/X86/X86ISelLowering.cpp
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Expand Up @@ -10112,7 +10112,15 @@ static SDValue lowerV2X128VectorShuffle(SDLoc DL, MVT VT, SDValue V1,

// Otherwise form a 128-bit permutation.
// FIXME: Detect zero-vector inputs and use the VPERM2X128 to zero that half.
unsigned PermMask = Mask[0] / 2 | (Mask[2] / 2) << 4;
int MaskLO = Mask[0];
if (MaskLO == SM_SentinelUndef)
MaskLO = Mask[1] == SM_SentinelUndef ? 0 : Mask[1];

int MaskHI = Mask[2];
if (MaskHI == SM_SentinelUndef)
MaskHI = Mask[3] == SM_SentinelUndef ? 0 : Mask[3];

unsigned PermMask = MaskLO / 2 | (MaskHI / 2) << 4;
return DAG.getNode(X86ISD::VPERM2X128, DL, VT, V1, V2,
DAG.getConstant(PermMask, MVT::i8));
}
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72 changes: 71 additions & 1 deletion llvm/test/CodeGen/X86/avx-vperm2x128.ll
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Expand Up @@ -172,13 +172,83 @@ entry:
define <8 x float> @F(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm1[0,1,0,1]
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3],ymm1[0,1]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 undef, i32 9, i32 undef, i32 11>
ret <8 x float> %shuffle
}

define <8 x float> @F2(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F2:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3,2,3]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 undef, i32 undef, i32 6, i32 7>
ret <8 x float> %shuffle
}

define <8 x float> @F3(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F3:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3],ymm1[0,1]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 undef, i32 undef, i32 10, i32 11>
ret <8 x float> %shuffle
}

define <8 x float> @F4(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F4:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3],ymm1[2,3]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 undef, i32 undef, i32 14, i32 15>
ret <8 x float> %shuffle
}

define <8 x float> @F5(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F5:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3,2,3]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 4, i32 5, i32 6, i32 7>
ret <8 x float> %shuffle
}

define <8 x float> @F6(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F6:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3],ymm1[0,1]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 undef, i32 undef, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11>
ret <8 x float> %shuffle
}

define <8 x float> @F7(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F7:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3,2,3]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 6, i32 7>
ret <8 x float> %shuffle
}

define <8 x float> @F8(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
; ALL-LABEL: F8:
; ALL: ## BB#0: ## %entry
; ALL-NEXT: vperm2f128 {{.*#+}} ymm0 = ymm0[2,3],ymm1[2,3]
; ALL-NEXT: retq
entry:
%shuffle = shufflevector <8 x float> %a, <8 x float> %b, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 14, i32 15>
ret <8 x float> %shuffle
}

;;;; Cases we must not select vperm2f128

define <8 x float> @G(<8 x float> %a, <8 x float> %b) nounwind uwtable readnone ssp {
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13 changes: 6 additions & 7 deletions llvm/test/CodeGen/X86/vector-shuffle-512-v8.ll
View file
Expand Up @@ -687,7 +687,7 @@ define <8 x double> @shuffle_v8f64_c348cda0(<8 x double> %a, <8 x double> %b) {
; ALL-LABEL: shuffle_v8f64_c348cda0:
; ALL: # BB#0:
; ALL-NEXT: vextractf64x4 $1, %zmm0, %ymm2
; ALL-NEXT: vperm2f128 {{.*#+}} ymm2 = ymm0[0,1],ymm2[0,1]
; ALL-NEXT: vperm2f128 {{.*#+}} ymm2 = ymm0[2,3],ymm2[0,1]
; ALL-NEXT: vextractf64x4 $1, %zmm1, %ymm3
; ALL-NEXT: vbroadcastsd %xmm1, %ymm4
; ALL-NEXT: vblendpd {{.*#+}} ymm4 = ymm3[0,1,2],ymm4[3]
Expand Down Expand Up @@ -1405,15 +1405,14 @@ define <8 x i64> @shuffle_v8i64_6caa87e5(<8 x i64> %a, <8 x i64> %b) {
; ALL-LABEL: shuffle_v8i64_6caa87e5:
; ALL: # BB#0:
; ALL-NEXT: vextracti64x4 $1, %zmm0, %ymm0
; ALL-NEXT: vperm2i128 {{.*#+}} ymm2 = ymm0[0,1,0,1]
; ALL-NEXT: vextracti64x4 $1, %zmm1, %ymm3
; ALL-NEXT: vpblendd {{.*#+}} ymm4 = ymm1[0,1,2,3],ymm3[4,5],ymm1[6,7]
; ALL-NEXT: vpblendd {{.*#+}} ymm2 = ymm4[0,1],ymm2[2,3],ymm4[4,5],ymm2[6,7]
; ALL-NEXT: vperm2i128 {{.*#+}} ymm0 = ymm0[2,3,0,1]
; ALL-NEXT: vpblendd {{.*#+}} ymm1 = ymm3[0,1,2,3],ymm1[4,5,6,7]
; ALL-NEXT: vextracti64x4 $1, %zmm1, %ymm2
; ALL-NEXT: vpblendd {{.*#+}} ymm3 = ymm1[0,1,2,3],ymm2[4,5],ymm1[6,7]
; ALL-NEXT: vpblendd {{.*#+}} ymm3 = ymm3[0,1],ymm0[2,3],ymm3[4,5],ymm0[6,7]
; ALL-NEXT: vpblendd {{.*#+}} ymm1 = ymm2[0,1,2,3],ymm1[4,5,6,7]
; ALL-NEXT: vpshufd {{.*#+}} ymm1 = ymm1[0,1,0,1,4,5,4,5]
; ALL-NEXT: vpblendd {{.*#+}} ymm0 = ymm0[0,1],ymm1[2,3,4,5,6,7]
; ALL-NEXT: vinserti64x4 $1, %ymm2, %zmm0, %zmm0
; ALL-NEXT: vinserti64x4 $1, %ymm3, %zmm0, %zmm0
; ALL-NEXT: retq
%shuffle = shufflevector <8 x i64> %a, <8 x i64> %b, <8 x i32> <i32 6, i32 12, i32 10, i32 10, i32 8, i32 7, i32 14, i32 5>
ret <8 x i64> %shuffle
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