[DAGCombiner] Recognise vector rotations with non-splat constants

Fixes PR33691.

Differential revision: https://reviews.llvm.org/D35381

llvm-svn: 308150

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index f2a487b..ab4578e 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4585,6 +4585,20 @@ SDNode *DAGCombiner::MatchRotatePosNeg(SDValue Shifted, SDValue Pos,
   return nullptr;
 }
 
+// if Left + Right == Sum (constant or constant splat vector)
+static bool sumMatchConstant(SDValue Left, SDValue Right, unsigned Sum,
+                             SelectionDAG &DAG, const SDLoc &DL) {
+  EVT ShiftVT = Left.getValueType();
+  if (ShiftVT != Right.getValueType()) return false;
+
+  SDValue ShiftSum = DAG.FoldConstantArithmetic(ISD::ADD, DL, ShiftVT,
+                         Left.getNode(), Right.getNode());
+  if (!ShiftSum) return false;
+
+  ConstantSDNode *CSum = isConstOrConstSplat(ShiftSum);
+  return CSum && CSum->getZExtValue() == Sum;
+}
+
 // MatchRotate - Handle an 'or' of two operands.  If this is one of the many
 // idioms for rotate, and if the target supports rotation instructions, generate
 // a rot[lr].
@@ -4630,30 +4644,24 @@ SDNode *DAGCombiner::MatchRotate(SDValue LHS, SDValue RHS, const SDLoc &DL) {
 
   // fold (or (shl x, C1), (srl x, C2)) -> (rotl x, C1)
   // fold (or (shl x, C1), (srl x, C2)) -> (rotr x, C2)
-  if (isConstOrConstSplat(LHSShiftAmt) && isConstOrConstSplat(RHSShiftAmt)) {
-    uint64_t LShVal = isConstOrConstSplat(LHSShiftAmt)->getZExtValue();
-    uint64_t RShVal = isConstOrConstSplat(RHSShiftAmt)->getZExtValue();
-    if ((LShVal + RShVal) != EltSizeInBits)
-      return nullptr;
-
+  if (sumMatchConstant(LHSShiftAmt, RHSShiftAmt, EltSizeInBits, DAG, DL)) {
     SDValue Rot = DAG.getNode(HasROTL ? ISD::ROTL : ISD::ROTR, DL, VT,
                               LHSShiftArg, HasROTL ? LHSShiftAmt : RHSShiftAmt);
 
     // If there is an AND of either shifted operand, apply it to the result.
     if (LHSMask.getNode() || RHSMask.getNode()) {
-      SDValue Mask = DAG.getAllOnesConstant(DL, VT);
+      SDValue AllOnes = DAG.getAllOnesConstant(DL, VT);
+      SDValue Mask = AllOnes;
 
       if (LHSMask.getNode()) {
-        APInt RHSBits = APInt::getLowBitsSet(EltSizeInBits, LShVal);
+        SDValue RHSBits = DAG.getNode(ISD::SRL, DL, VT, AllOnes, RHSShiftAmt);
         Mask = DAG.getNode(ISD::AND, DL, VT, Mask,
-                           DAG.getNode(ISD::OR, DL, VT, LHSMask,
-                                       DAG.getConstant(RHSBits, DL, VT)));
+                           DAG.getNode(ISD::OR, DL, VT, LHSMask, RHSBits));
       }
       if (RHSMask.getNode()) {
-        APInt LHSBits = APInt::getHighBitsSet(EltSizeInBits, RShVal);
+        SDValue LHSBits = DAG.getNode(ISD::SHL, DL, VT, AllOnes, LHSShiftAmt);
         Mask = DAG.getNode(ISD::AND, DL, VT, Mask,
-                           DAG.getNode(ISD::OR, DL, VT, RHSMask,
-                                       DAG.getConstant(LHSBits, DL, VT)));
+                           DAG.getNode(ISD::OR, DL, VT, RHSMask, LHSBits));
       }
 
       Rot = DAG.getNode(ISD::AND, DL, VT, Rot, Mask);

diff --git a/llvm/test/CodeGen/X86/combine-rotates.ll b/llvm/test/CodeGen/X86/combine-rotates.ll
index 713ee5d..dc971f5 100644 (file)
--- a/llvm/test/CodeGen/X86/combine-rotates.ll
+++ b/llvm/test/CodeGen/X86/combine-rotates.ll
@@ -6,12 +6,7 @@
 define <4 x i32> @combine_vec_rot_rot(<4 x i32> %x) {
 ; XOP-LABEL: combine_vec_rot_rot:
 ; XOP:       # BB#0:
-; XOP-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm1
-; XOP-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm0
-; XOP-NEXT:    vpor %xmm0, %xmm1, %xmm0
-; XOP-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm1
-; XOP-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm0
-; XOP-NEXT:    vpor %xmm0, %xmm1, %xmm0
+; XOP-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm0
 ; XOP-NEXT:    retq
 ;
 ; AVX512-LABEL: combine_vec_rot_rot:

diff --git a/llvm/test/CodeGen/X86/rotate_vec.ll b/llvm/test/CodeGen/X86/rotate_vec.ll
index 453b4e0..8fb000b 100644 (file)
--- a/llvm/test/CodeGen/X86/rotate_vec.ll
+++ b/llvm/test/CodeGen/X86/rotate_vec.ll
@@ -15,9 +15,7 @@ define <4 x i32> @rot_v4i32_splat(<4 x i32> %x) {
 define <4 x i32> @rot_v4i32_non_splat(<4 x i32> %x) {
 ; CHECK-LABEL: rot_v4i32_non_splat:
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    vpsrlvd {{.*}}(%rip), %xmm0, %xmm1
-; CHECK-NEXT:    vpsllvd {{.*}}(%rip), %xmm0, %xmm0
-; CHECK-NEXT:    vpor %xmm0, %xmm1, %xmm0
+; CHECK-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm0
 ; CHECK-NEXT:    retq
   %1 = lshr <4 x i32> %x, <i32 1, i32 2, i32 3, i32 4>
   %2 = shl <4 x i32> %x, <i32 31, i32 30, i32 29, i32 28>
@@ -43,12 +41,8 @@ define <4 x i32> @rot_v4i32_splat_2masks(<4 x i32> %x) {
 define <4 x i32> @rot_v4i32_non_splat_2masks(<4 x i32> %x) {
 ; CHECK-LABEL: rot_v4i32_non_splat_2masks:
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    vpsrlvd {{.*}}(%rip), %xmm0, %xmm1
-; CHECK-NEXT:    vpxor %xmm2, %xmm2, %xmm2
-; CHECK-NEXT:    vpblendw {{.*#+}} xmm1 = xmm2[0],xmm1[1],xmm2[2],xmm1[3],xmm2[4],xmm1[5],xmm2[6],xmm1[7]
-; CHECK-NEXT:    vpsllvd {{.*}}(%rip), %xmm0, %xmm0
-; CHECK-NEXT:    vpblendw {{.*#+}} xmm0 = xmm2[0,1,2],xmm0[3],xmm2[4,5,6],xmm0[7]
-; CHECK-NEXT:    vpor %xmm0, %xmm1, %xmm0
+; CHECK-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm0
+; CHECK-NEXT:    vpand {{.*}}(%rip), %xmm0, %xmm0
 ; CHECK-NEXT:    retq
   %1 = lshr <4 x i32> %x, <i32 1, i32 2, i32 3, i32 4>
   %2 = and <4 x i32> %1, <i32 4294901760, i32 4294901760, i32 4294901760, i32 4294901760>

diff --git a/llvm/test/CodeGen/X86/vector-rotate-128.ll b/llvm/test/CodeGen/X86/vector-rotate-128.ll
index 00921d7..893ceb6 100644 (file)
--- a/llvm/test/CodeGen/X86/vector-rotate-128.ll
+++ b/llvm/test/CodeGen/X86/vector-rotate-128.ll
@@ -851,21 +851,10 @@ define <2 x i64> @constant_rotate_v2i64(<2 x i64> %a) nounwind {
 ; AVX512-NEXT:    vpor %xmm0, %xmm1, %xmm0
 ; AVX512-NEXT:    retq
 ;
-; XOPAVX1-LABEL: constant_rotate_v2i64:
-; XOPAVX1:       # BB#0:
-; XOPAVX1-NEXT:    vpshlq {{.*}}(%rip), %xmm0, %xmm1
-; XOPAVX1-NEXT:    vpxor %xmm2, %xmm2, %xmm2
-; XOPAVX1-NEXT:    vpsubq {{.*}}(%rip), %xmm2, %xmm2
-; XOPAVX1-NEXT:    vpshlq %xmm2, %xmm0, %xmm0
-; XOPAVX1-NEXT:    vpor %xmm0, %xmm1, %xmm0
-; XOPAVX1-NEXT:    retq
-;
-; XOPAVX2-LABEL: constant_rotate_v2i64:
-; XOPAVX2:       # BB#0:
-; XOPAVX2-NEXT:    vpsllvq {{.*}}(%rip), %xmm0, %xmm1
-; XOPAVX2-NEXT:    vpsrlvq {{.*}}(%rip), %xmm0, %xmm0
-; XOPAVX2-NEXT:    vpor %xmm0, %xmm1, %xmm0
-; XOPAVX2-NEXT:    retq
+; XOP-LABEL: constant_rotate_v2i64:
+; XOP:       # BB#0:
+; XOP-NEXT:    vprotq {{.*}}(%rip), %xmm0, %xmm0
+; XOP-NEXT:    retq
 ;
 ; X32-SSE-LABEL: constant_rotate_v2i64:
 ; X32-SSE:       # BB#0:
@@ -958,19 +947,10 @@ define <4 x i32> @constant_rotate_v4i32(<4 x i32> %a) nounwind {
 ; AVX512-NEXT:    vpor %xmm0, %xmm1, %xmm0
 ; AVX512-NEXT:    retq
 ;
-; XOPAVX1-LABEL: constant_rotate_v4i32:
-; XOPAVX1:       # BB#0:
-; XOPAVX1-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm1
-; XOPAVX1-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm0
-; XOPAVX1-NEXT:    vpor %xmm0, %xmm1, %xmm0
-; XOPAVX1-NEXT:    retq
-;
-; XOPAVX2-LABEL: constant_rotate_v4i32:
-; XOPAVX2:       # BB#0:
-; XOPAVX2-NEXT:    vpsllvd {{.*}}(%rip), %xmm0, %xmm1
-; XOPAVX2-NEXT:    vpsrlvd {{.*}}(%rip), %xmm0, %xmm0
-; XOPAVX2-NEXT:    vpor %xmm0, %xmm1, %xmm0
-; XOPAVX2-NEXT:    retq
+; XOP-LABEL: constant_rotate_v4i32:
+; XOP:       # BB#0:
+; XOP-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm0
+; XOP-NEXT:    retq
 ;
 ; X32-SSE-LABEL: constant_rotate_v4i32:
 ; X32-SSE:       # BB#0:
@@ -1100,11 +1080,7 @@ define <8 x i16> @constant_rotate_v8i16(<8 x i16> %a) nounwind {
 ;
 ; XOP-LABEL: constant_rotate_v8i16:
 ; XOP:       # BB#0:
-; XOP-NEXT:    vpshlw {{.*}}(%rip), %xmm0, %xmm1
-; XOP-NEXT:    vpxor %xmm2, %xmm2, %xmm2
-; XOP-NEXT:    vpsubw {{.*}}(%rip), %xmm2, %xmm2
-; XOP-NEXT:    vpshlw %xmm2, %xmm0, %xmm0
-; XOP-NEXT:    vpor %xmm0, %xmm1, %xmm0
+; XOP-NEXT:    vprotw {{.*}}(%rip), %xmm0, %xmm0
 ; XOP-NEXT:    retq
 ;
 ; X32-SSE-LABEL: constant_rotate_v8i16:
@@ -1281,11 +1257,7 @@ define <16 x i8> @constant_rotate_v16i8(<16 x i8> %a) nounwind {
 ;
 ; XOP-LABEL: constant_rotate_v16i8:
 ; XOP:       # BB#0:
-; XOP-NEXT:    vpshlb {{.*}}(%rip), %xmm0, %xmm1
-; XOP-NEXT:    vpxor %xmm2, %xmm2, %xmm2
-; XOP-NEXT:    vpsubb {{.*}}(%rip), %xmm2, %xmm2
-; XOP-NEXT:    vpshlb %xmm2, %xmm0, %xmm0
-; XOP-NEXT:    vpor %xmm0, %xmm1, %xmm0
+; XOP-NEXT:    vprotb {{.*}}(%rip), %xmm0, %xmm0
 ; XOP-NEXT:    retq
 ;
 ; X32-SSE-LABEL: constant_rotate_v16i8:

diff --git a/llvm/test/CodeGen/X86/vector-rotate-256.ll b/llvm/test/CodeGen/X86/vector-rotate-256.ll
index 3eb0962..f231429 100644 (file)
--- a/llvm/test/CodeGen/X86/vector-rotate-256.ll
+++ b/llvm/test/CodeGen/X86/vector-rotate-256.ll
@@ -558,21 +558,18 @@ define <8 x i32> @constant_rotate_v8i32(<8 x i32> %a) nounwind {
 ;
 ; XOPAVX1-LABEL: constant_rotate_v8i32:
 ; XOPAVX1:       # BB#0:
-; XOPAVX1-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm1
-; XOPAVX1-NEXT:    vextractf128 $1, %ymm0, %xmm2
-; XOPAVX1-NEXT:    vpshld {{.*}}(%rip), %xmm2, %xmm3
-; XOPAVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm1, %ymm1
-; XOPAVX1-NEXT:    vpshld {{.*}}(%rip), %xmm0, %xmm0
-; XOPAVX1-NEXT:    vpshld {{.*}}(%rip), %xmm2, %xmm2
-; XOPAVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm0, %ymm0
-; XOPAVX1-NEXT:    vorps %ymm0, %ymm1, %ymm0
+; XOPAVX1-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm1
+; XOPAVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
+; XOPAVX1-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm0
+; XOPAVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
 ; XOPAVX1-NEXT:    retq
 ;
 ; XOPAVX2-LABEL: constant_rotate_v8i32:
 ; XOPAVX2:       # BB#0:
-; XOPAVX2-NEXT:    vpsllvd {{.*}}(%rip), %ymm0, %ymm1
-; XOPAVX2-NEXT:    vpsrlvd {{.*}}(%rip), %ymm0, %ymm0
-; XOPAVX2-NEXT:    vpor %ymm0, %ymm1, %ymm0
+; XOPAVX2-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm1
+; XOPAVX2-NEXT:    vextracti128 $1, %ymm0, %xmm0
+; XOPAVX2-NEXT:    vprotd {{.*}}(%rip), %xmm0, %xmm0
+; XOPAVX2-NEXT:    vinserti128 $1, %xmm0, %ymm1, %ymm0
 ; XOPAVX2-NEXT:    retq
   %shl = shl <8 x i32> %a, <i32 4, i32 5, i32 6, i32 7, i32 8, i32 9, i32 10, i32 11>
   %lshr = lshr <8 x i32> %a, <i32 28, i32 27, i32 26, i32 25, i32 24, i32 23, i32 22, i32 21>
@@ -643,30 +640,18 @@ define <16 x i16> @constant_rotate_v16i16(<16 x i16> %a) nounwind {
 ;
 ; XOPAVX1-LABEL: constant_rotate_v16i16:
 ; XOPAVX1:       # BB#0:
-; XOPAVX1-NEXT:    vpshlw {{.*}}(%rip), %xmm0, %xmm1
-; XOPAVX1-NEXT:    vextractf128 $1, %ymm0, %xmm2
-; XOPAVX1-NEXT:    vpshlw {{.*}}(%rip), %xmm2, %xmm3
-; XOPAVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm1, %ymm1
-; XOPAVX1-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; XOPAVX1-NEXT:    vpsubw {{.*}}(%rip), %xmm3, %xmm4
-; XOPAVX1-NEXT:    vpshlw %xmm4, %xmm2, %xmm2
-; XOPAVX1-NEXT:    vpsubw {{.*}}(%rip), %xmm3, %xmm3
-; XOPAVX1-NEXT:    vpshlw %xmm3, %xmm0, %xmm0
-; XOPAVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm0, %ymm0
-; XOPAVX1-NEXT:    vorps %ymm0, %ymm1, %ymm0
+; XOPAVX1-NEXT:    vprotw {{.*}}(%rip), %xmm0, %xmm1
+; XOPAVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
+; XOPAVX1-NEXT:    vprotw {{.*}}(%rip), %xmm0, %xmm0
+; XOPAVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
 ; XOPAVX1-NEXT:    retq
 ;
 ; XOPAVX2-LABEL: constant_rotate_v16i16:
 ; XOPAVX2:       # BB#0:
-; XOPAVX2-NEXT:    vpmullw {{.*}}(%rip), %ymm0, %ymm1
-; XOPAVX2-NEXT:    vpxor %xmm2, %xmm2, %xmm2
-; XOPAVX2-NEXT:    vpsubw {{.*}}(%rip), %xmm2, %xmm3
-; XOPAVX2-NEXT:    vextracti128 $1, %ymm0, %xmm4
-; XOPAVX2-NEXT:    vpshlw %xmm3, %xmm4, %xmm3
-; XOPAVX2-NEXT:    vpsubw {{.*}}(%rip), %xmm2, %xmm2
-; XOPAVX2-NEXT:    vpshlw %xmm2, %xmm0, %xmm0
-; XOPAVX2-NEXT:    vinserti128 $1, %xmm3, %ymm0, %ymm0
-; XOPAVX2-NEXT:    vpor %ymm0, %ymm1, %ymm0
+; XOPAVX2-NEXT:    vprotw {{.*}}(%rip), %xmm0, %xmm1
+; XOPAVX2-NEXT:    vextracti128 $1, %ymm0, %xmm0
+; XOPAVX2-NEXT:    vprotw {{.*}}(%rip), %xmm0, %xmm0
+; XOPAVX2-NEXT:    vinserti128 $1, %xmm0, %ymm1, %ymm0
 ; XOPAVX2-NEXT:    retq
   %shl = shl <16 x i16> %a, <i16 0, i16 1, i16 2, i16 3, i16 4, i16 5, i16 6, i16 7, i16 8, i16 9, i16 10, i16 11, i16 12, i16 13, i16 14, i16 15>
   %lshr = lshr <16 x i16> %a, <i16 16, i16 15, i16 14, i16 13, i16 12, i16 11, i16 10, i16 9, i16 8, i16 7, i16 6, i16 5, i16 4, i16 3, i16 2, i16 1>
@@ -768,32 +753,20 @@ define <32 x i8> @constant_rotate_v32i8(<32 x i8> %a) nounwind {
 ;
 ; XOPAVX1-LABEL: constant_rotate_v32i8:
 ; XOPAVX1:       # BB#0:
-; XOPAVX1-NEXT:    vmovdqa {{.*#+}} xmm1 = [0,1,2,3,4,5,6,7,8,7,6,5,4,3,2,1]
-; XOPAVX1-NEXT:    vextractf128 $1, %ymm0, %xmm2
-; XOPAVX1-NEXT:    vpshlb %xmm1, %xmm2, %xmm3
-; XOPAVX1-NEXT:    vpshlb %xmm1, %xmm0, %xmm1
-; XOPAVX1-NEXT:    vinsertf128 $1, %xmm3, %ymm1, %ymm1
-; XOPAVX1-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; XOPAVX1-NEXT:    vpsubb {{.*}}(%rip), %xmm3, %xmm3
-; XOPAVX1-NEXT:    vpshlb %xmm3, %xmm2, %xmm2
-; XOPAVX1-NEXT:    vpshlb %xmm3, %xmm0, %xmm0
-; XOPAVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm0, %ymm0
-; XOPAVX1-NEXT:    vorps %ymm0, %ymm1, %ymm0
+; XOPAVX1-NEXT:    vextractf128 $1, %ymm0, %xmm1
+; XOPAVX1-NEXT:    vmovdqa {{.*#+}} xmm2 = [0,1,2,3,4,5,6,7,8,7,6,5,4,3,2,1]
+; XOPAVX1-NEXT:    vprotb %xmm2, %xmm1, %xmm1
+; XOPAVX1-NEXT:    vprotb %xmm2, %xmm0, %xmm0
+; XOPAVX1-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; XOPAVX1-NEXT:    retq
 ;
 ; XOPAVX2-LABEL: constant_rotate_v32i8:
 ; XOPAVX2:       # BB#0:
-; XOPAVX2-NEXT:    vmovdqa {{.*#+}} xmm1 = [0,1,2,3,4,5,6,7,8,7,6,5,4,3,2,1]
-; XOPAVX2-NEXT:    vextracti128 $1, %ymm0, %xmm2
-; XOPAVX2-NEXT:    vpshlb %xmm1, %xmm2, %xmm3
-; XOPAVX2-NEXT:    vpshlb %xmm1, %xmm0, %xmm1
-; XOPAVX2-NEXT:    vinserti128 $1, %xmm3, %ymm1, %ymm1
-; XOPAVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; XOPAVX2-NEXT:    vpsubb {{.*}}(%rip), %xmm3, %xmm3
-; XOPAVX2-NEXT:    vpshlb %xmm3, %xmm2, %xmm2
-; XOPAVX2-NEXT:    vpshlb %xmm3, %xmm0, %xmm0
-; XOPAVX2-NEXT:    vinserti128 $1, %xmm2, %ymm0, %ymm0
-; XOPAVX2-NEXT:    vpor %ymm0, %ymm1, %ymm0
+; XOPAVX2-NEXT:    vextracti128 $1, %ymm0, %xmm1
+; XOPAVX2-NEXT:    vmovdqa {{.*#+}} xmm2 = [0,1,2,3,4,5,6,7,8,7,6,5,4,3,2,1]
+; XOPAVX2-NEXT:    vprotb %xmm2, %xmm1, %xmm1
+; XOPAVX2-NEXT:    vprotb %xmm2, %xmm0, %xmm0
+; XOPAVX2-NEXT:    vinserti128 $1, %xmm1, %ymm0, %ymm0
 ; XOPAVX2-NEXT:    retq
   %shl = shl <32 x i8> %a, <i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 7, i8 6, i8 5, i8 4, i8 3, i8 2, i8 1, i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 7, i8 6, i8 5, i8 4, i8 3, i8 2, i8 1>
   %lshr = lshr <32 x i8> %a, <i8 8, i8 7, i8 6, i8 5, i8 4, i8 3, i8 2, i8 1, i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 7, i8 6, i8 5, i8 4, i8 3, i8 2, i8 1, i8 0, i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7>