[llvm] r218115 - [x86] Recognize that we can use duplication to widen v16i8 shuffles due

[Chandler Carruth]

Author: chandlerc
Date: Fri Sep 19 04:45:21 2014
New Revision: 218115

URL: http://llvm.org/viewvc/llvm-project?rev=218115&view=rev
Log:
[x86] Recognize that we can use duplication to widen v16i8 shuffles due
to undef lanes as well as defined widenable lanes. This dramatically
improves the lowering we use for undef-shuffles in a zext-ish pattern
for SSE2.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/vector-shuffle-128-v16.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=218115&r1=218114&r2=218115&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Sep 19 04:45:21 2014
@@ -8716,10 +8716,10 @@ static SDValue lowerV16I8VectorShuffle(S
     // FIXME: We should check for other patterns which can be widened into an
     // i16 shuffle as well.
     auto canWidenViaDuplication = [](ArrayRef<int> Mask) {
-      for (int i = 0; i < 16; i += 2) {
-        if (Mask[i] != Mask[i + 1])
+      for (int i = 0; i < 16; i += 2)
+        if (Mask[i] != -1 && Mask[i + 1] != -1 && Mask[i] != Mask[i + 1])
           return false;
-      }
+
       return true;
     };
     auto tryToWidenViaDuplication = [&]() -> SDValue {

Modified: llvm/trunk/test/CodeGen/X86/vector-shuffle-128-v16.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-shuffle-128-v16.ll?rev=218115&r1=218114&r2=218115&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vector-shuffle-128-v16.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vector-shuffle-128-v16.ll Fri Sep 19 04:45:21 2014
@@ -512,10 +512,16 @@ define <16 x i8> @shuffle_v16i8_15_16_17
 }
 
 define <16 x i8> @shuffle_v16i8_00_uu_uu_uu_uu_uu_uu_uu_01_uu_uu_uu_uu_uu_uu_uu(<16 x i8> %a) {
+; SSE2-LABEL: @shuffle_v16i8_00_uu_uu_uu_uu_uu_uu_uu_01_uu_uu_uu_uu_uu_uu_uu
+; SSE2:       # BB#0:
+; SSE2-NEXT:    punpcklbw {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
+; SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,0,3]
+; SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,5,5,6,7]
+; SSE2-NEXT:    retq
+;
 ; SSSE3-LABEL: @shuffle_v16i8_00_uu_uu_uu_uu_uu_uu_uu_01_uu_uu_uu_uu_uu_uu_uu
 ; SSSE3:       # BB#0:
-; SSSE3-NEXT:    pshufb {{.*}}    # xmm0 = xmm0[0],zero,zero,zero,xmm0[1],zero,zero,zero,zero,zero,zero,zero,zero,zero,zero,zero
-; SSSE3-NEXT:    punpcklbw {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
+; SSSE3-NEXT:    pshufb {{.*}}    # xmm0 = xmm0[0,{{[0-9]+,[0-9]+,[0-9]+,[0-9]+,[0-9]+,[0-9]+,[0-9]+}},1,{{[0-9]+,[0-9]+,[0-9]+,[0-9]+,[0-9]+,[0-9]+,[0-9]+}}]
 ; SSSE3-NEXT:    retq
 ;
 ; SSE41-LABEL: @shuffle_v16i8_00_uu_uu_uu_uu_uu_uu_uu_01_uu_uu_uu_uu_uu_uu_uu
@@ -549,17 +555,14 @@ define <16 x i8> @shuffle_v16i8_00_zz_zz
 define <16 x i8> @shuffle_v16i8_00_uu_uu_uu_01_uu_uu_uu_02_uu_uu_uu_03_uu_uu_uu(<16 x i8> %a) {
 ; SSE2-LABEL: @shuffle_v16i8_00_uu_uu_uu_01_uu_uu_uu_02_uu_uu_uu_03_uu_uu_uu
 ; SSE2:       # BB#0:
-; SSE2-NEXT:    pxor %[[X1:xmm[0-9]+]], %[[X1]]
-; SSE2-NEXT:    punpcklbw {{.*}} # xmm0 = xmm0[0],[[X1]][0],xmm0[1],[[X1]][1],xmm0[2],[[X1]][2],xmm0[3],[[X1]][3],xmm0[4],[[X1]][4],xmm0[5],[[X1]][5],xmm0[6],[[X1]][6],xmm0[7],[[X1]][7]
-; SSE2-NEXT:    punpcklwd {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3]
-; SSE2-NEXT:    packuswb %xmm0, %xmm0
 ; SSE2-NEXT:    punpcklbw {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
+; SSE2-NEXT:    punpcklwd {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3]
 ; SSE2-NEXT:    retq
 ;
 ; SSSE3-LABEL: @shuffle_v16i8_00_uu_uu_uu_01_uu_uu_uu_02_uu_uu_uu_03_uu_uu_uu
 ; SSSE3:       # BB#0:
-; SSSE3-NEXT:    pshufb {{.*}}    # xmm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero,zero,zero,zero,zero,zero,zero,zero,zero
 ; SSSE3-NEXT:    punpcklbw {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7]
+; SSSE3-NEXT:    punpcklwd {{.*}} # xmm0 = xmm0[0,0,1,1,2,2,3,3]
 ; SSSE3-NEXT:    retq
 ;
 ; SSE41-LABEL: @shuffle_v16i8_00_uu_uu_uu_01_uu_uu_uu_02_uu_uu_uu_03_uu_uu_uu