[llvm] r321251 - [X86] Use PSHUFB for v32i16 shuffles before falling back to VPERMW/VPERMI2W.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Thu Dec 21 00:22:51 2017
New Revision: 321251

URL: http://llvm.org/viewvc/llvm-project?rev=321251&view=rev
Log:
[X86] Use PSHUFB for v32i16 shuffles before falling back to VPERMW/VPERMI2W.

PSHUFB has the ability to implicitly 0 elements which VPERMI2W can't do. So give a chance to use it first.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v32.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=321251&r1=321250&r2=321251&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Dec 21 00:22:51 2017
@@ -14080,6 +14080,10 @@ static SDValue lowerV32I16VectorShuffle(
                                                 Zeroable, Subtarget, DAG))
     return Blend;
 
+  if (SDValue PSHUFB = lowerVectorShuffleWithPSHUFB(
+          DL, MVT::v32i16, Mask, V1, V2, Zeroable, Subtarget, DAG))
+    return PSHUFB;
+
   return lowerVectorShuffleWithPERMV(DL, MVT::v32i16, Mask, V1, V2, DAG);
 }
 

Modified: llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v32.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v32.ll?rev=321251&r1=321250&r2=321251&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v32.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vector-shuffle-512-v32.ll Thu Dec 21 00:22:51 2017
@@ -353,3 +353,18 @@ define <8 x i16> @pr32967(<32 x i16> %v)
  %shuffle = shufflevector <32 x i16> %v, <32 x i16> undef, <8 x i32> <i32 1,i32 5,i32 9,i32 13,i32 17,i32 21,i32 25,i32 29>
  ret <8 x i16> %shuffle
 }
+
+define <32 x i16> @shuffle_v32i16_07_zz_05_zz_03_zz_01_zz_15_zz_13_zz_11_zz_09_zz_23_zz_21_zz_19_zz_17_zz_31_zz_29_zz_27_zz_25_zz(<32 x i16> %a) {
+; KNL-LABEL: shuffle_v32i16_07_zz_05_zz_03_zz_01_zz_15_zz_13_zz_11_zz_09_zz_23_zz_21_zz_19_zz_17_zz_31_zz_29_zz_27_zz_25_zz:
+; KNL:       ## %bb.0:
+; KNL-NEXT:    vpshufb {{.*#+}} ymm0 = ymm0[14,15],zero,zero,ymm0[10,11],zero,zero,ymm0[6,7],zero,zero,ymm0[2,3],zero,zero,ymm0[30,31],zero,zero,ymm0[26,27],zero,zero,ymm0[22,23],zero,zero,ymm0[18,19],zero,zero
+; KNL-NEXT:    vpshufb {{.*#+}} ymm1 = ymm1[14,15],zero,zero,ymm1[10,11],zero,zero,ymm1[6,7],zero,zero,ymm1[2,3],zero,zero,ymm1[30,31],zero,zero,ymm1[26,27],zero,zero,ymm1[22,23],zero,zero,ymm1[20,21],zero,zero
+; KNL-NEXT:    retq
+;
+; SKX-LABEL: shuffle_v32i16_07_zz_05_zz_03_zz_01_zz_15_zz_13_zz_11_zz_09_zz_23_zz_21_zz_19_zz_17_zz_31_zz_29_zz_27_zz_25_zz:
+; SKX:       ## %bb.0:
+; SKX-NEXT:    vpshufb {{.*#+}} zmm0 = zmm0[14,15],zero,zero,zmm0[10,11],zero,zero,zmm0[6,7],zero,zero,zmm0[2,3],zero,zero,zmm0[30,31],zero,zero,zmm0[26,27],zero,zero,zmm0[22,23],zero,zero,zmm0[18,19],zero,zero,zmm0[46,47],zero,zero,zmm0[42,43],zero,zero,zmm0[38,39],zero,zero,zmm0[34,35],zero,zero,zmm0[62,63],zero,zero,zmm0[58,59],zero,zero,zmm0[54,55],zero,zero,zmm0[52,53],zero,zero
+; SKX-NEXT:    retq
+  %shuffle = shufflevector <32 x i16> zeroinitializer, <32 x i16> %a, <32 x i32> <i32 39, i32 0, i32 37, i32 0, i32 35, i32 0, i32 33, i32 0, i32 47, i32 0, i32 45, i32 0, i32 43, i32 0, i32 41, i32 0, i32 55, i32 0, i32 53, i32 0, i32 51, i32 0, i32 49, i32 0, i32 63, i32 0, i32 61, i32 0, i32 59, i32 0, i32 58, i32 0>
+  ret <32 x i16> %shuffle
+}