[x86] Fix a miscompile in the new shuffle lowering uncovered by

a bootstrap.

I managed to mis-remember how PACKUS worked on x86, and was using undef
for the high bytes instead of zero. The fix is fairly obvious.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211922 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index c50f44daaee8c3903224bff1fe25d1fa7ffa5b5b..fa80717f99479621a10d63e7c88a3476482f3608 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -7712,19 +7712,19 @@ static SDValue lowerV16I8VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
 
     return DAG.getNode(X86ISD::UNPCKL, DL, MVT::v16i8, Evens, Odds);
   }
-
-  SDValue LoV1 = DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
-                             DAG.getNode(X86ISD::UNPCKL, DL, MVT::v16i8, V1,
-                                         DAG.getUNDEF(MVT::v8i16)));
-  SDValue HiV1 = DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
-                             DAG.getNode(X86ISD::UNPCKH, DL, MVT::v16i8, V1,
-                                         DAG.getUNDEF(MVT::v8i16)));
-  SDValue LoV2 = DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
-                             DAG.getNode(X86ISD::UNPCKL, DL, MVT::v16i8, V2,
-                                         DAG.getUNDEF(MVT::v8i16)));
-  SDValue HiV2 = DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
-                             DAG.getNode(X86ISD::UNPCKH, DL, MVT::v16i8, V2,
-                                         DAG.getUNDEF(MVT::v8i16)));
+  SDValue Zero = getZeroVector(MVT::v8i16, Subtarget, DAG, DL);
+  SDValue LoV1 =
+      DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
+                  DAG.getNode(X86ISD::UNPCKL, DL, MVT::v16i8, V1, Zero));
+  SDValue HiV1 =
+      DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
+                  DAG.getNode(X86ISD::UNPCKH, DL, MVT::v16i8, V1, Zero));
+  SDValue LoV2 =
+      DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
+                  DAG.getNode(X86ISD::UNPCKL, DL, MVT::v16i8, V2, Zero));
+  SDValue HiV2 =
+      DAG.getNode(ISD::BITCAST, DL, MVT::v8i16,
+                  DAG.getNode(X86ISD::UNPCKH, DL, MVT::v16i8, V2, Zero));
 
   int V1LoBlendMask[8] = {-1, -1, -1, -1, -1, -1, -1, -1};
   int V1HiBlendMask[8] = {-1, -1, -1, -1, -1, -1, -1, -1};

diff --git a/test/CodeGen/X86/vector-shuffle-128-v16.ll b/test/CodeGen/X86/vector-shuffle-128-v16.ll
index 6203aedcc132ba84319b9d40565ae371427dca0a..b5e0b79088faa6b4e5adefdb4960072a86492b49 100644 (file)
--- a/test/CodeGen/X86/vector-shuffle-128-v16.ll
+++ b/test/CodeGen/X86/vector-shuffle-128-v16.ll
@@ -23,7 +23,8 @@ 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:         punpcklbw %xmm0, %xmm1
+; CHECK-SSE2:         pxor %xmm2, %xmm2
+; CHECK-SSE2-NEXT:    punpcklbw %xmm2, %xmm1
 ; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm1 = xmm1[0,1,0,3]
 ; 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]
@@ -37,14 +38,15 @@ define <16 x i8> @shuffle_v16i8_16_00_16_01_16_02_16_03_16_04_16_05_16_06_16_07(
 
 define <16 x i8> @shuffle_v16i8_03_02_01_00_07_06_05_04_11_10_09_08_15_14_13_12(<16 x i8> %a, <16 x i8> %b) {
 ; CHECK-SSE2-LABEL: @shuffle_v16i8_03_02_01_00_07_06_05_04_11_10_09_08_15_14_13_12
-; CHECK-SSE2:         movdqa %xmm0, %xmm1
-; CHECK-SSE2-NEXT:    punpckhbw %xmm0, %xmm1
-; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm1 = xmm1[3,2,1,0,4,5,6,7]
-; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm1 = xmm1[0,1,2,3,7,6,5,4]
-; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2:         pxor %xmm1, %xmm1
+; CHECK-SSE2-NEXT:    movdqa %xmm0, %xmm2
+; CHECK-SSE2-NEXT:    punpckhbw %xmm1, %xmm2
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm2 = xmm2[3,2,1,0,4,5,6,7]
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm2 = xmm2[0,1,2,3,7,6,5,4]
+; CHECK-SSE2-NEXT:    punpcklbw %xmm1, %xmm0
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[3,2,1,0,4,5,6,7]
 ; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,7,6,5,4]
-; CHECK-SSE2-NEXT:    packuswb %xmm1, %xmm0
+; CHECK-SSE2-NEXT:    packuswb %xmm2, %xmm0
 ; CHECK-SSE2-NEXT:    retq
   %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 3, i32 2, i32 1, i32 0, i32 7, i32 6, i32 5, i32 4, i32 11, i32 10, i32 9, i32 8, i32 15, i32 14, i32 13, i32 12>
   ret <16 x i8> %shuffle
@@ -52,10 +54,11 @@ define <16 x i8> @shuffle_v16i8_03_02_01_00_07_06_05_04_11_10_09_08_15_14_13_12(
 
 define <16 x i8> @shuffle_v16i8_03_02_01_00_07_06_05_04_19_18_17_16_23_22_21_20(<16 x i8> %a, <16 x i8> %b) {
 ; CHECK-SSE2-LABEL: @shuffle_v16i8_03_02_01_00_07_06_05_04_19_18_17_16_23_22_21_20
-; CHECK-SSE2:         punpcklbw %xmm0, %xmm1
+; CHECK-SSE2:         pxor %xmm2, %xmm2
+; CHECK-SSE2-NEXT:    punpcklbw %xmm2, %xmm1
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm1 = xmm1[3,2,1,0,4,5,6,7]
 ; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm1 = xmm1[0,1,2,3,7,6,5,4]
-; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    punpcklbw %xmm2, %xmm0
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[3,2,1,0,4,5,6,7]
 ; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,7,6,5,4]
 ; CHECK-SSE2-NEXT:    packuswb %xmm1, %xmm0
@@ -66,19 +69,20 @@ define <16 x i8> @shuffle_v16i8_03_02_01_00_07_06_05_04_19_18_17_16_23_22_21_20(
 
 define <16 x i8> @shuffle_v16i8_03_02_01_00_31_30_29_28_11_10_09_08_23_22_21_20(<16 x i8> %a, <16 x i8> %b) {
 ; CHECK-SSE2-LABEL: @shuffle_v16i8_03_02_01_00_31_30_29_28_11_10_09_08_23_22_21_20
-; CHECK-SSE2:         movdqa %xmm1, %xmm2
-; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm2
-; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm2 = xmm2[0,1,2,3,7,6,5,4]
-; CHECK-SSE2-NEXT:    movdqa %xmm0, %xmm3
-; CHECK-SSE2-NEXT:    punpckhbw %xmm0, %xmm3
-; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm3 = xmm3[3,2,1,0,4,5,6,7]
-; CHECK-SSE2-NEXT:    shufpd {{.*}} # xmm3 = xmm3[0],xmm2[1]
-; CHECK-SSE2-NEXT:    punpckhbw %xmm0, %xmm1
+; CHECK-SSE2:         pxor %xmm2, %xmm2
+; CHECK-SSE2-NEXT:    movdqa %xmm1, %xmm3
+; CHECK-SSE2-NEXT:    punpcklbw %xmm2, %xmm3
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm3 = xmm3[0,1,2,3,7,6,5,4]
+; CHECK-SSE2-NEXT:    movdqa %xmm0, %xmm4
+; CHECK-SSE2-NEXT:    punpckhbw %xmm2, %xmm4
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm4 = xmm4[3,2,1,0,4,5,6,7]
+; CHECK-SSE2-NEXT:    shufpd {{.*}} # xmm4 = xmm4[0],xmm3[1]
+; CHECK-SSE2-NEXT:    punpckhbw %xmm2, %xmm1
 ; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm1 = xmm1[0,1,2,3,7,6,5,4]
-; CHECK-SSE2-NEXT:    punpcklbw %xmm0, %xmm0
+; CHECK-SSE2-NEXT:    punpcklbw %xmm2, %xmm0
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[3,2,1,0,4,5,6,7]
 ; CHECK-SSE2-NEXT:    shufpd {{.*}} # xmm0 = xmm0[0],xmm1[1]
-; CHECK-SSE2-NEXT:    packuswb %xmm3, %xmm0
+; CHECK-SSE2-NEXT:    packuswb %xmm4, %xmm0
 ; CHECK-SSE2-NEXT:    retq
   %shuffle = shufflevector <16 x i8> %a, <16 x i8> %b, <16 x i32> <i32 3, i32 2, i32 1, i32 0, i32 31, i32 30, i32 29, i32 28, i32 11, i32 10, i32 9, i32 8, i32 23, i32 22, i32 21, i32 20>
   ret <16 x i8> %shuffle