[X86] Try to zero elts when lowering 256-bit shuffle with PSHUFB.

Otherwise we fallback to a blend of PSHUFBs later on.

Differential Revision: http://reviews.llvm.org/D19661

llvm-svn: 271113

2 files changed, 34 insertions, 0 deletions

diff --git a/llvm/test/CodeGen/X86/vector-shuffle-256-v16.ll b/llvm/test/CodeGen/X86/vector-shuffle-256-v16.ll
index cc12397a9a7..23fbba61dab 100644
--- a/llvm/test/CodeGen/X86/vector-shuffle-256-v16.ll
+++ b/llvm/test/CodeGen/X86/vector-shuffle-256-v16.ll
@@ -2378,6 +2378,24 @@ define <16 x i16> @shuffle_v16i16_04_05_06_03_uu_uu_uu_uu_12_13_14_11_uu_uu_uu_u
   ret <16 x i16> %shuffle
 }
 
+define <16 x i16> @shuffle_v16i16_01_zz_02_zz_04_uu_06_07_08_09_10_11_12_13_14_15(<16 x i16> %a) {
+; AVX1-LABEL: shuffle_v16i16_01_zz_02_zz_04_uu_06_07_08_09_10_11_12_13_14_15:
+; AVX1:       # BB#0:
+; AVX1-NEXT:    vpshuflw {{.*#+}} xmm1 = xmm0[1,1,2,3,4,5,6,7]
+; AVX1-NEXT:    vpxor %xmm2, %xmm2, %xmm2
+; AVX1-NEXT:    vpblendw {{.*#+}} xmm1 = xmm1[0],xmm2[1],xmm1[2],xmm2[3],xmm1[4,5,6,7]
+; AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
+; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
+; AVX1-NEXT:    retq
+;
+; AVX2-LABEL: shuffle_v16i16_01_zz_02_zz_04_uu_06_07_08_09_10_11_12_13_14_15:
+; AVX2:       # BB#0:
+; AVX2-NEXT:    vpshufb {{.*#+}} ymm0 = ymm0[2,3],zero,zero,ymm0[4,5],zero,zero,ymm0[8,9,u,u,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31]
+; AVX2-NEXT:    retq
+  %shuffle = shufflevector <16 x i16> %a, <16 x i16> zeroinitializer, <16 x i32> <i32 1, i32 16, i32 2, i32 16, i32 4, i32 undef, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15>
+  ret <16 x i16> %shuffle
+}
+
 define <16 x i16> @shuffle_v16i16_00_01_02_07_04_05_06_11_08_09_10_15_12_13_14_11(<16 x i16> %a, <16 x i16> %b) {
 ; AVX1-LABEL: shuffle_v16i16_00_01_02_07_04_05_06_11_08_09_10_15_12_13_14_11:
 ; AVX1:       # BB#0:
diff --git a/llvm/test/CodeGen/X86/vector-shuffle-256-v32.ll b/llvm/test/CodeGen/X86/vector-shuffle-256-v32.ll
index 846e606a361..80cbaab164c 100644
--- a/llvm/test/CodeGen/X86/vector-shuffle-256-v32.ll
+++ b/llvm/test/CodeGen/X86/vector-shuffle-256-v32.ll
@@ -953,6 +953,22 @@ define <32 x i8> @shuffle_v32i8_zz_01_zz_03_zz_05_zz_07_zz_09_zz_11_zz_13_zz_15_
   ret <32 x i8> %shuffle
 }
 
+define <32 x i8> @shuffle_v32i8_01_zz_02_zz_04_uu_06_07_08_09_10_11_12_13_14_15_u6_17_18_19_20_21_22_23_24_25_26_27_28_29_30_31(<32 x i8> %a) {
+; AVX1-LABEL: shuffle_v32i8_01_zz_02_zz_04_uu_06_07_08_09_10_11_12_13_14_15_u6_17_18_19_20_21_22_23_24_25_26_27_28_29_30_31:
+; AVX1:       # BB#0:
+; AVX1-NEXT:    vpshufb {{.*#+}} xmm1 = xmm0[1],zero,xmm0[2],zero,xmm0[4,u,6,7,8,9,10,11,12,13,14,15]
+; AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
+; AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
+; AVX1-NEXT:    retq
+;
+; AVX2-LABEL: shuffle_v32i8_01_zz_02_zz_04_uu_06_07_08_09_10_11_12_13_14_15_u6_17_18_19_20_21_22_23_24_25_26_27_28_29_30_31:
+; AVX2:       # BB#0:
+; AVX2-NEXT:    vpshufb {{.*#+}} ymm0 = ymm0[1],zero,ymm0[2],zero,ymm0[4,u,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31]
+; AVX2-NEXT:    retq
+  %shuffle = shufflevector <32 x i8> %a, <32 x i8> zeroinitializer, <32 x i32> <i32 1, i32 32, i32 2, i32 32, i32 4, i32 undef, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11, i32 12, i32 13, i32 14, i32 15, i32 16, i32 17, i32 18, i32 19, i32 20, i32 21, i32 22, i32 23, i32 24, i32 25, i32 26, i32 27, i32 28, i32 29, i32 30, i32 31>
+  ret <32 x i8> %shuffle
+}
+
 define <32 x i8> @shuffle_v32i8_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32(<32 x i8> %a, <32 x i8> %b) {
 ; AVX1-LABEL: shuffle_v32i8_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32_00_32:
 ; AVX1:       # BB#0: