[x86] Add handling for splat-like widenings of v16i8 shuffles.

These show up really frequently, not the least with actual splats. =] We
lowered these quite badly before. The new code path tries to widen i8
shuffles to i16 shuffles in a splat-like way. There are still some
inefficiencies in our i16 splat logic though, so we aren't really done
here.

Also, for certain patterns (bit of a gather-and-splat) we still
generate pretty silly code, and I've left a fixme for addressing it.
However, I'm not actually worried about this code pattern as much. The
old shuffle lowering generates a 29 instruction monstrosity for it that
should execute much more slowly.

llvm-svn: 211974

1 files changed, 89 insertions, 5 deletions

diff --git a/llvm/test/CodeGen/X86/vector-shuffle-128-v16.ll b/llvm/test/CodeGen/X86/vector-shuffle-128-v16.ll
index b5e0b79088f..f3a0931f731 100644
--- a/llvm/test/CodeGen/X86/vector-shuffle-128-v16.ll
+++ b/llvm/test/CodeGen/X86/vector-shuffle-128-v16.ll
@@ -3,6 +3,93 @@
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-unknown"
 
+define <16 x i8> @shuffle_v16i8_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00(<16 x i8> %a, <16 x i8> %b) {
+; CHECK-SSE2-LABEL: @shuffle_v16i8_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00_00
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,0,3]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,0,0,0,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,4,4,4,4]
+; CHECK-SSE2-NEXT:    retq
+  %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0>
+  ret <16 x i8> %shuffle
+}
+
+define <16 x i8> @shuffle_v16i8_00_00_00_00_00_00_00_00_01_01_01_01_01_01_01_01(<16 x i8> %a, <16 x i8> %b) {
+; CHECK-SSE2-LABEL: @shuffle_v16i8_00_00_00_00_00_00_00_00_01_01_01_01_01_01_01_01
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,0,3]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,0,0,0,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,5,5,5,5]
+; CHECK-SSE2-NEXT:    retq
+  %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1>
+  ret <16 x i8> %shuffle
+}
+
+define <16 x i8> @shuffle_v16i8_00_00_00_00_00_00_00_00_08_08_08_08_08_08_08_08(<16 x i8> %a, <16 x i8> %b) {
+; CHECK-SSE2-LABEL: @shuffle_v16i8_00_00_00_00_00_00_00_00_08_08_08_08_08_08_08_08
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    pxor %xmm1, %xmm1
+; CHECK-SSE2-NEXT:    movdqa %xmm0, %xmm2
+; CHECK-SSE2-NEXT:    punpckhbw %xmm1, %xmm2
+; CHECK-SSE2-NEXT:    punpcklbw %xmm1, %xmm0
+; CHECK-SSE2-NEXT:    punpcklwd %xmm2, %xmm0
+; CHECK-SSE2-NEXT:    packuswb %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,0,3]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,0,0,0,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,5,5,5,5]
+; CHECK-SSE2-NEXT:    retq
+  %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 0, i32 8, i32 8, i32 8, i32 8, i32 8, i32 8, i32 8, i32 8>
+  ret <16 x i8> %shuffle
+}
+
+define <16 x i8> @shuffle_v16i8_00_00_00_00_01_01_01_01_02_02_02_02_03_03_03_03(<16 x i8> %a, <16 x i8> %b) {
+; CHECK-SSE2-LABEL: @shuffle_v16i8_00_00_00_00_01_01_01_01_02_02_02_02_03_03_03_03
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,2,1]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,0,1,1,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,6,6,7,7]
+; CHECK-SSE2-NEXT:    retq
+  %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 0, i32 0, i32 0, i32 0, i32 1, i32 1, i32 1, i32 1, i32 2, i32 2, i32 2, i32 2, i32 3, i32 3, i32 3, i32 3>
+  ret <16 x i8> %shuffle
+}
+
+define <16 x i8> @shuffle_v16i8_00_00_00_00_04_04_04_04_08_08_08_08_12_12_12_12(<16 x i8> %a, <16 x i8> %b) {
+; CHECK-SSE2-LABEL: @shuffle_v16i8_00_00_00_00_04_04_04_04_08_08_08_08_12_12_12_12
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    pxor %xmm1, %xmm1
+; CHECK-SSE2-NEXT:    movdqa %xmm0, %xmm2
+; CHECK-SSE2-NEXT:    punpcklbw %xmm1, %xmm2
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm2 = xmm2[2,1,2,3]
+; CHECK-SSE2-NEXT:    punpckhbw %xmm1, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,2,2,3]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,2,2,3,4,5,6,7]
+; CHECK-SSE2-NEXT:    punpcklwd %xmm2, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,0,3]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[1,0,2,3,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,5,5,6,7]
+; CHECK-SSE2-NEXT:    packuswb %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,2,0,1]
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,0,2,2,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,5,5,6,6]
+; CHECK-SSE2-NEXT:    retq
+  %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 0, i32 0, i32 0, i32 0, i32 4, i32 4, i32 4, i32 4, i32 8, i32 8, i32 8, i32 8, i32 12, i32 12, i32 12, i32 12>
+  ret <16 x i8> %shuffle
+}
+
+define <16 x i8> @shuffle_v16i8_00_00_01_01_02_02_03_03_04_04_05_05_06_06_07_07(<16 x i8> %a, <16 x i8> %b) {
+; CHECK-SSE2-LABEL: @shuffle_v16i8_00_00_01_01_02_02_03_03_04_04_05_05_06_06_07_07
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    retq
+  %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 0, i32 0, i32 1, i32 1, i32 2, i32 2, i32 3, i32 3, i32 4, i32 4, i32 5, i32 5, i32 6, i32 6, i32 7, i32 7>
+  ret <16 x i8> %shuffle
+}
+
 define <16 x i8> @shuffle_v16i8_0101010101010101(<16 x i8> %a, <16 x i8> %b) {
 ; CHECK-SSE2-LABEL: @shuffle_v16i8_0101010101010101
 ; CHECK-SSE2:         pshufd {{.*}} # xmm0 = xmm0[0,1,0,3]
@@ -23,12 +110,9 @@ define <16 x i8> @shuffle_v16i8_00_16_01_17_02_18_03_19_04_20_05_21_06_22_07_23(
 
 define <16 x i8> @shuffle_v16i8_16_00_16_01_16_02_16_03_16_04_16_05_16_06_16_07(<16 x i8> %a, <16 x i8> %b) {
 ; CHECK-SSE2-LABEL: @shuffle_v16i8_16_00_16_01_16_02_16_03_16_04_16_05_16_06_16_07
-; CHECK-SSE2:         pxor %xmm2, %xmm2
-; CHECK-SSE2-NEXT:    punpcklbw %xmm2, %xmm1
-; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm1 = xmm1[0,1,0,3]
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    punpcklbw %xmm1, %xmm1
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm1 = xmm1[0,0,0,0,4,5,6,7]
-; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm1 = xmm1[0,1,2,3,4,4,4,4]
-; CHECK-SSE2-NEXT:    packuswb %xmm0, %xmm1
 ; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm1
 ; CHECK-SSE2-NEXT:    movdqa %xmm1, %xmm0
 ; CHECK-SSE2-NEXT:    retq