[DAGCombiner] limit shuffle to extend transform (PR40146)

It's dangerous to knowingly create an illegal vector type
no matter what stage of combining we're in.

This prevents the missed folding/scalarization seen in:
https://bugs.llvm.org/show_bug.cgi?id=40146

llvm-svn: 350034

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 93af1f4..dda4f01 100644 (file)
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -17092,8 +17092,7 @@ static SDValue combineShuffleOfScalars(ShuffleVectorSDNode *SVN,
 static SDValue combineShuffleToVectorExtend(ShuffleVectorSDNode *SVN,
                                             SelectionDAG &DAG,
                                             const TargetLowering &TLI,
-                                            bool LegalOperations,
-                                            bool LegalTypes) {
+                                            bool LegalOperations) {
   EVT VT = SVN->getValueType(0);
   bool IsBigEndian = DAG.getDataLayout().isBigEndian();
 
@@ -17129,7 +17128,9 @@ static SDValue combineShuffleToVectorExtend(ShuffleVectorSDNode *SVN,
 
     EVT OutSVT = EVT::getIntegerVT(*DAG.getContext(), EltSizeInBits * Scale);
     EVT OutVT = EVT::getVectorVT(*DAG.getContext(), OutSVT, NumElts / Scale);
-    if (!LegalTypes || TLI.isTypeLegal(OutVT))
+    // Never create an illegal type. Only create unsupported operations if we
+    // are pre-legalization.
+    if (TLI.isTypeLegal(OutVT))
       if (!LegalOperations ||
           TLI.isOperationLegalOrCustom(ISD::ANY_EXTEND_VECTOR_INREG, OutVT))
         return DAG.getBitcast(VT,
@@ -17439,7 +17440,7 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) {
     return SDValue(N, 0);
 
   // Match shuffles that can be converted to any_vector_extend_in_reg.
-  if (SDValue V = combineShuffleToVectorExtend(SVN, DAG, TLI, LegalOperations, LegalTypes))
+  if (SDValue V = combineShuffleToVectorExtend(SVN, DAG, TLI, LegalOperations))
     return V;
 
   // Combine "truncate_vector_in_reg" style shuffles.

diff --git a/llvm/test/CodeGen/X86/vec_cast3.ll b/llvm/test/CodeGen/X86/vec_cast3.ll
index fdf7c00..e4ff93a 100644 (file)
--- a/llvm/test/CodeGen/X86/vec_cast3.ll
+++ b/llvm/test/CodeGen/X86/vec_cast3.ll
@@ -240,86 +240,18 @@ define <2 x i32> @cvt_v2f32_v2u32(<2 x float> %src) {
 define <32 x i8> @PR40146(<4 x i64> %x) {
 ; CHECK-LABEL: PR40146:
 ; CHECK:       ## %bb.0:
-; CHECK-NEXT:    vpextrd $2, %xmm0, %eax
-; CHECK-NEXT:    movzbl %ah, %ecx
-; CHECK-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; CHECK-NEXT:    vpinsrb $0, %eax, %xmm1, %xmm2
-; CHECK-NEXT:    vpinsrb $2, %ecx, %xmm2, %xmm2
-; CHECK-NEXT:    movl %eax, %ecx
-; CHECK-NEXT:    shrl $16, %ecx
-; CHECK-NEXT:    vpinsrb $4, %ecx, %xmm2, %xmm2
-; CHECK-NEXT:    vpextrd $3, %xmm0, %ecx
-; CHECK-NEXT:    shrl $24, %eax
-; CHECK-NEXT:    vpinsrb $6, %eax, %xmm2, %xmm2
-; CHECK-NEXT:    movzbl %ch, %eax
-; CHECK-NEXT:    vpinsrb $8, %ecx, %xmm2, %xmm2
-; CHECK-NEXT:    vpinsrb $10, %eax, %xmm2, %xmm2
-; CHECK-NEXT:    movl %ecx, %eax
-; CHECK-NEXT:    shrl $16, %eax
-; CHECK-NEXT:    vpinsrb $12, %eax, %xmm2, %xmm2
-; CHECK-NEXT:    vmovd %xmm0, %eax
-; CHECK-NEXT:    shrl $24, %ecx
-; CHECK-NEXT:    vpinsrb $14, %ecx, %xmm2, %xmm2
-; CHECK-NEXT:    movzbl %ah, %ecx
-; CHECK-NEXT:    vpinsrb $0, %eax, %xmm1, %xmm1
-; CHECK-NEXT:    vpinsrb $2, %ecx, %xmm1, %xmm1
-; CHECK-NEXT:    movl %eax, %ecx
-; CHECK-NEXT:    shrl $16, %ecx
-; CHECK-NEXT:    vpinsrb $4, %ecx, %xmm1, %xmm1
-; CHECK-NEXT:    vpextrd $1, %xmm0, %ecx
-; CHECK-NEXT:    shrl $24, %eax
-; CHECK-NEXT:    vpinsrb $6, %eax, %xmm1, %xmm0
-; CHECK-NEXT:    movzbl %ch, %eax
-; CHECK-NEXT:    vpinsrb $8, %ecx, %xmm0, %xmm0
-; CHECK-NEXT:    vpinsrb $10, %eax, %xmm0, %xmm0
-; CHECK-NEXT:    movl %ecx, %eax
-; CHECK-NEXT:    shrl $16, %eax
-; CHECK-NEXT:    vpinsrb $12, %eax, %xmm0, %xmm0
-; CHECK-NEXT:    shrl $24, %ecx
-; CHECK-NEXT:    vpinsrb $14, %ecx, %xmm0, %xmm0
-; CHECK-NEXT:    vinsertf128 $1, %xmm2, %ymm0, %ymm0
+; CHECK-NEXT:    vpshufd {{.*#+}} xmm1 = xmm0[2,3,0,1]
+; CHECK-NEXT:    vpmovzxbw {{.*#+}} xmm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero,xmm0[4],zero,xmm0[5],zero,xmm0[6],zero,xmm0[7],zero
+; CHECK-NEXT:    vpmovzxbw {{.*#+}} xmm1 = xmm1[0],zero,xmm1[1],zero,xmm1[2],zero,xmm1[3],zero,xmm1[4],zero,xmm1[5],zero,xmm1[6],zero,xmm1[7],zero
+; CHECK-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; CHECK-NEXT:    retl
 ;
 ; CHECK-WIDE-LABEL: PR40146:
 ; CHECK-WIDE:       ## %bb.0:
-; CHECK-WIDE-NEXT:    vpextrd $2, %xmm0, %eax
-; CHECK-WIDE-NEXT:    movzbl %ah, %ecx
-; CHECK-WIDE-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; CHECK-WIDE-NEXT:    vpinsrb $0, %eax, %xmm1, %xmm2
-; CHECK-WIDE-NEXT:    vpinsrb $2, %ecx, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    movl %eax, %ecx
-; CHECK-WIDE-NEXT:    shrl $16, %ecx
-; CHECK-WIDE-NEXT:    vpinsrb $4, %ecx, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    vpextrd $3, %xmm0, %ecx
-; CHECK-WIDE-NEXT:    shrl $24, %eax
-; CHECK-WIDE-NEXT:    vpinsrb $6, %eax, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    movzbl %ch, %eax
-; CHECK-WIDE-NEXT:    vpinsrb $8, %ecx, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    vpinsrb $10, %eax, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    movl %ecx, %eax
-; CHECK-WIDE-NEXT:    shrl $16, %eax
-; CHECK-WIDE-NEXT:    vpinsrb $12, %eax, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    vmovd %xmm0, %eax
-; CHECK-WIDE-NEXT:    shrl $24, %ecx
-; CHECK-WIDE-NEXT:    vpinsrb $14, %ecx, %xmm2, %xmm2
-; CHECK-WIDE-NEXT:    movzbl %ah, %ecx
-; CHECK-WIDE-NEXT:    vpinsrb $0, %eax, %xmm1, %xmm1
-; CHECK-WIDE-NEXT:    vpinsrb $2, %ecx, %xmm1, %xmm1
-; CHECK-WIDE-NEXT:    movl %eax, %ecx
-; CHECK-WIDE-NEXT:    shrl $16, %ecx
-; CHECK-WIDE-NEXT:    vpinsrb $4, %ecx, %xmm1, %xmm1
-; CHECK-WIDE-NEXT:    vpextrd $1, %xmm0, %ecx
-; CHECK-WIDE-NEXT:    shrl $24, %eax
-; CHECK-WIDE-NEXT:    vpinsrb $6, %eax, %xmm1, %xmm0
-; CHECK-WIDE-NEXT:    movzbl %ch, %eax
-; CHECK-WIDE-NEXT:    vpinsrb $8, %ecx, %xmm0, %xmm0
-; CHECK-WIDE-NEXT:    vpinsrb $10, %eax, %xmm0, %xmm0
-; CHECK-WIDE-NEXT:    movl %ecx, %eax
-; CHECK-WIDE-NEXT:    shrl $16, %eax
-; CHECK-WIDE-NEXT:    vpinsrb $12, %eax, %xmm0, %xmm0
-; CHECK-WIDE-NEXT:    shrl $24, %ecx
-; CHECK-WIDE-NEXT:    vpinsrb $14, %ecx, %xmm0, %xmm0
-; CHECK-WIDE-NEXT:    vinsertf128 $1, %xmm2, %ymm0, %ymm0
+; CHECK-WIDE-NEXT:    vpshufd {{.*#+}} xmm1 = xmm0[2,3,0,1]
+; CHECK-WIDE-NEXT:    vpmovzxbw {{.*#+}} xmm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero,xmm0[4],zero,xmm0[5],zero,xmm0[6],zero,xmm0[7],zero
+; CHECK-WIDE-NEXT:    vpmovzxbw {{.*#+}} xmm1 = xmm1[0],zero,xmm1[1],zero,xmm1[2],zero,xmm1[3],zero,xmm1[4],zero,xmm1[5],zero,xmm1[6],zero,xmm1[7],zero
+; CHECK-WIDE-NEXT:    vinsertf128 $1, %xmm1, %ymm0, %ymm0
 ; CHECK-WIDE-NEXT:    retl
   %perm = shufflevector <4 x i64> %x, <4 x i64> undef, <4 x i32> <i32 0, i32 undef, i32 1, i32 undef>
   %t1 = bitcast <4 x i64> %perm to <32 x i8>