[X86][AVX512BW] AVX512BW can sign-extend v32i8 to v32i16 for simpler v32i8 multiplies.

Only pre-AVX512BW targets need to split v32i8 vectors.

llvm-svn: 264509

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index c27a3f7..6d9e48b 100644 (file)
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -18910,8 +18910,9 @@ static SDValue LowerMUL(SDValue Op, const X86Subtarget &Subtarget,
   if (VT == MVT::v16i8 || VT == MVT::v32i8) {
     if (Subtarget.hasInt256()) {
       // For 256-bit vectors, split into 128-bit vectors to allow the
-      // sign-extension to occur.
-      if (VT == MVT::v32i8)
+      // sign-extension to occur. We don't need this on AVX512BW as we can
+      // safely sign-extend to v32i16.
+      if (VT == MVT::v32i8 && !Subtarget.hasBWI())
         return Lower256IntArith(Op, DAG);
 
       MVT ExVT = MVT::getVectorVT(MVT::i16, VT.getVectorNumElements());

diff --git a/llvm/test/CodeGen/X86/pmul.ll b/llvm/test/CodeGen/X86/pmul.ll
index 89c35ba..d5fffa8 100644 (file)
--- a/llvm/test/CodeGen/X86/pmul.ll
+++ b/llvm/test/CodeGen/X86/pmul.ll
@@ -473,15 +473,11 @@ define <32 x i8> @mul_v32i8c(<32 x i8> %i) nounwind  {
 ;
 ; AVX512BW-LABEL: mul_v32i8c:
 ; AVX512BW:       # BB#0: # %entry
-; AVX512BW-NEXT:    vpmovsxbw %xmm0, %ymm1
-; AVX512BW-NEXT:    vpmovsxbw {{.*}}(%rip), %ymm2
-; AVX512BW-NEXT:    vpmullw %ymm2, %ymm1, %ymm1
-; AVX512BW-NEXT:    vpmovwb %zmm1, %ymm1
-; AVX512BW-NEXT:    vextracti128 $1, %ymm0, %xmm0
-; AVX512BW-NEXT:    vpmovsxbw %xmm0, %ymm0
-; AVX512BW-NEXT:    vpmullw %ymm2, %ymm0, %ymm0
+; AVX512BW-NEXT:    vmovaps {{.*#+}} ymm1 = [117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117,117]
+; AVX512BW-NEXT:    vpmovsxbw %ymm1, %zmm1
+; AVX512BW-NEXT:    vpmovsxbw %ymm0, %zmm0
+; AVX512BW-NEXT:    vpmullw %zmm1, %zmm0, %zmm0
 ; AVX512BW-NEXT:    vpmovwb %zmm0, %ymm0
-; AVX512BW-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
 ; AVX512BW-NEXT:    retq
 entry:
   %A = mul <32 x i8> %i, < i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117, i8 117 >
@@ -678,17 +674,10 @@ define <32 x i8> @mul_v32i8(<32 x i8> %i, <32 x i8> %j) nounwind  {
 ;
 ; AVX512BW-LABEL: mul_v32i8:
 ; AVX512BW:       # BB#0: # %entry
-; AVX512BW-NEXT:    vpmovsxbw %xmm1, %ymm2
-; AVX512BW-NEXT:    vpmovsxbw %xmm0, %ymm3
-; AVX512BW-NEXT:    vpmullw %ymm2, %ymm3, %ymm2
-; AVX512BW-NEXT:    vpmovwb %zmm2, %ymm2
-; AVX512BW-NEXT:    vextracti128 $1, %ymm1, %xmm1
-; AVX512BW-NEXT:    vpmovsxbw %xmm1, %ymm1
-; AVX512BW-NEXT:    vextracti128 $1, %ymm0, %xmm0
-; AVX512BW-NEXT:    vpmovsxbw %xmm0, %ymm0
-; AVX512BW-NEXT:    vpmullw %ymm1, %ymm0, %ymm0
+; AVX512BW-NEXT:    vpmovsxbw %ymm1, %zmm1
+; AVX512BW-NEXT:    vpmovsxbw %ymm0, %zmm0
+; AVX512BW-NEXT:    vpmullw %zmm1, %zmm0, %zmm0
 ; AVX512BW-NEXT:    vpmovwb %zmm0, %ymm0
-; AVX512BW-NEXT:    vinsertf128 $1, %xmm0, %ymm2, %ymm0
 ; AVX512BW-NEXT:    retq
 entry:
   %A = mul <32 x i8> %i, %j