[X86] combineTargetShuffle - fold (vzmovl (shift x, y)) -> (shift (vzmovl x), y) (llvm#141579)

Move VZEXT_MOVL nodes up through shift nodes.

We should be trying harder to move VZEXT_MOVL towards any associated SCALAR_TO_VECTOR nodes to make use of MOVD/Q implicit zeroing of upper elements.

Fixes llvm#141475

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -42368,6 +42368,20 @@ static SDValue combineTargetShuffle(SDValue N, const SDLoc &DL,
   case X86ISD::VZEXT_MOVL: {
     SDValue N0 = N.getOperand(0);
 
+    // Fold (vzmovl (shift x, y)) -> (shift (vzmovl x), y)
+    // Zeroing out the upper elements means we're just shifting a zero value.
+    // TODO: Try harder to move vzmovl upward towards SCALAR_TO_VECTOR nodes.
+    // TODO: Move this to canonicalizeShuffleWithOp once we add zero handling.
+    if (N0.getOpcode() == X86ISD::VSHL || N0.getOpcode() == X86ISD::VSHLI ||
+        N0.getOpcode() == X86ISD::VSRL || N0.getOpcode() == X86ISD::VSRLI ||
+        N0.getOpcode() == X86ISD::VSRA || N0.getOpcode() == X86ISD::VSRAI) {
+      if (N0.hasOneUse())
+        return DAG.getNode(
+            N0.getOpcode(), DL, VT,
+            DAG.getNode(X86ISD::VZEXT_MOVL, DL, VT, N0.getOperand(0)),
+            N0.getOperand(1));
+    }
+
     // If this a vzmovl of a full vector load, replace it with a vzload, unless
     // the load is volatile.
     if (N0.hasOneUse() && ISD::isNormalLoad(N0.getNode())) {

llvm/test/CodeGen/X86/codegen-no-uselist-constantdata.ll

@@ -36,10 +36,8 @@ define <16 x i8> @load_null_offset() {
 ; CHECK-LABEL: load_null_offset:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    movzbl 11, %eax
-; CHECK-NEXT:    movd %eax, %xmm1
-; CHECK-NEXT:    pslld $8, %xmm1
-; CHECK-NEXT:    xorps %xmm0, %xmm0
-; CHECK-NEXT:    movss {{.*#+}} xmm0 = xmm1[0],xmm0[1,2,3]
+; CHECK-NEXT:    movd %eax, %xmm0
+; CHECK-NEXT:    pslld $8, %xmm0
 ; CHECK-NEXT:    retq
   %gep.null = getelementptr i8, ptr null, i64 11
   %load = load i8, ptr %gep.null, align 1

llvm/test/CodeGen/X86/urem-seteq-illegal-types.ll

@@ -147,15 +147,14 @@ define <3 x i1> @test_urem_vec(<3 x i11> %X) nounwind {
 ; SSE2-NEXT:    pshufd {{.*#+}} xmm1 = xmm3[0,2,2,3]
 ; SSE2-NEXT:    punpckldq {{.*#+}} xmm2 = xmm2[0],xmm1[0],xmm2[1],xmm1[1]
 ; SSE2-NEXT:    movdqa {{.*#+}} xmm1 = [2047,2047,2047,2047]
-; SSE2-NEXT:    movdqa %xmm0, %xmm3
-; SSE2-NEXT:    pand %xmm1, %xmm3
-; SSE2-NEXT:    psrld $1, %xmm3
-; SSE2-NEXT:    movss {{.*#+}} xmm2 = xmm3[0],xmm2[1,2,3]
-; SSE2-NEXT:    pslld $10, %xmm0
-; SSE2-NEXT:    xorps %xmm3, %xmm3
+; SSE2-NEXT:    pxor %xmm3, %xmm3
 ; SSE2-NEXT:    movss {{.*#+}} xmm3 = xmm0[0],xmm3[1,2,3]
-; SSE2-NEXT:    orps %xmm2, %xmm3
-; SSE2-NEXT:    andps %xmm1, %xmm3
+; SSE2-NEXT:    pand %xmm1, %xmm0
+; SSE2-NEXT:    psrld $1, %xmm0
+; SSE2-NEXT:    movss {{.*#+}} xmm2 = xmm0[0],xmm2[1,2,3]
+; SSE2-NEXT:    pslld $10, %xmm3
+; SSE2-NEXT:    por %xmm2, %xmm3
+; SSE2-NEXT:    pand %xmm1, %xmm3
 ; SSE2-NEXT:    pcmpgtd {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm3
 ; SSE2-NEXT:    movdqa %xmm3, -{{[0-9]+}}(%rsp)
 ; SSE2-NEXT:    movzbl -{{[0-9]+}}(%rsp), %eax
@@ -175,9 +174,9 @@ define <3 x i1> @test_urem_vec(<3 x i11> %X) nounwind {
 ; SSE41-NEXT:    pand %xmm1, %xmm2
 ; SSE41-NEXT:    psrld $1, %xmm2
 ; SSE41-NEXT:    pblendw {{.*#+}} xmm2 = xmm2[0,1],xmm0[2,3,4,5,6,7]
-; SSE41-NEXT:    pslld $10, %xmm0
 ; SSE41-NEXT:    pxor %xmm3, %xmm3
 ; SSE41-NEXT:    pblendw {{.*#+}} xmm3 = xmm0[0,1],xmm3[2,3,4,5,6,7]
+; SSE41-NEXT:    pslld $10, %xmm3
 ; SSE41-NEXT:    por %xmm2, %xmm3
 ; SSE41-NEXT:    pand %xmm1, %xmm3
 ; SSE41-NEXT:    pcmpgtd {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm3
@@ -200,9 +199,9 @@ define <3 x i1> @test_urem_vec(<3 x i11> %X) nounwind {
 ; AVX1-NEXT:    vpand %xmm1, %xmm0, %xmm2
 ; AVX1-NEXT:    vpsrld $1, %xmm2, %xmm2
 ; AVX1-NEXT:    vpblendw {{.*#+}} xmm2 = xmm2[0,1],xmm0[2,3,4,5,6,7]
-; AVX1-NEXT:    vpslld $10, %xmm0, %xmm0
 ; AVX1-NEXT:    vpxor %xmm3, %xmm3, %xmm3
 ; AVX1-NEXT:    vpblendw {{.*#+}} xmm0 = xmm0[0,1],xmm3[2,3,4,5,6,7]
+; AVX1-NEXT:    vpslld $10, %xmm0, %xmm0
 ; AVX1-NEXT:    vpor %xmm0, %xmm2, %xmm0
 ; AVX1-NEXT:    vpand %xmm1, %xmm0, %xmm0
 ; AVX1-NEXT:    vpcmpgtd {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0, %xmm0

llvm/test/CodeGen/X86/vec_insert-5.ll

@@ -10,16 +10,16 @@ define void  @t1(i32 %a, ptr %P) nounwind {
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
 ; X86-NEXT:    movd {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; X86-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[1,0,1,1]
 ; X86-NEXT:    pslld $12, %xmm0
-; X86-NEXT:    psllq $32, %xmm0
 ; X86-NEXT:    movq %xmm0, (%eax)
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: t1:
 ; X64:       # %bb.0:
 ; X64-NEXT:    movd %edi, %xmm0
-; X64-NEXT:    pslld $12, %xmm0
 ; X64-NEXT:    psllq $32, %xmm0
+; X64-NEXT:    pslld $12, %xmm0
 ; X64-NEXT:    movq %xmm0, (%rsi)
 ; X64-NEXT:    retq
  %tmp12 = shl i32 %a, 12

llvm/test/CodeGen/X86/vector-shuffle-combining.ll

@@ -3547,57 +3547,19 @@ define <16 x i8> @PR107289(<16 x i8> %0) {
 }
 
 define <8 x i16> @PR141475(i32 %in) {
-; SSE2-LABEL: PR141475:
-; SSE2:       # %bb.0:
-; SSE2-NEXT:    movd %edi, %xmm0
-; SSE2-NEXT:    pslld $1, %xmm0
-; SSE2-NEXT:    xorps %xmm1, %xmm1
-; SSE2-NEXT:    movss {{.*#+}} xmm1 = xmm0[0],xmm1[1,2,3]
-; SSE2-NEXT:    pshuflw {{.*#+}} xmm0 = xmm1[0,0,0,0,4,5,6,7]
-; SSE2-NEXT:    retq
-;
-; SSSE3-LABEL: PR141475:
-; SSSE3:       # %bb.0:
-; SSSE3-NEXT:    movd %edi, %xmm0
-; SSSE3-NEXT:    pslld $1, %xmm0
-; SSSE3-NEXT:    xorps %xmm1, %xmm1
-; SSSE3-NEXT:    movss {{.*#+}} xmm1 = xmm0[0],xmm1[1,2,3]
-; SSSE3-NEXT:    pshuflw {{.*#+}} xmm0 = xmm1[0,0,0,0,4,5,6,7]
-; SSSE3-NEXT:    retq
-;
-; SSE41-LABEL: PR141475:
-; SSE41:       # %bb.0:
-; SSE41-NEXT:    movd %edi, %xmm0
-; SSE41-NEXT:    pslld $1, %xmm0
-; SSE41-NEXT:    pxor %xmm1, %xmm1
-; SSE41-NEXT:    pblendw {{.*#+}} xmm1 = xmm0[0,1],xmm1[2,3,4,5,6,7]
-; SSE41-NEXT:    pshuflw {{.*#+}} xmm0 = xmm1[0,0,0,0,4,5,6,7]
-; SSE41-NEXT:    retq
-;
-; AVX1-LABEL: PR141475:
-; AVX1:       # %bb.0:
-; AVX1-NEXT:    vmovd %edi, %xmm0
-; AVX1-NEXT:    vpslld $1, %xmm0, %xmm0
-; AVX1-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX1-NEXT:    vpblendw {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3,4,5,6,7]
-; AVX1-NEXT:    vpshuflw {{.*#+}} xmm0 = xmm0[0,0,0,0,4,5,6,7]
-; AVX1-NEXT:    retq
-;
-; AVX2-SLOW-LABEL: PR141475:
-; AVX2-SLOW:       # %bb.0:
-; AVX2-SLOW-NEXT:    vmovd %edi, %xmm0
-; AVX2-SLOW-NEXT:    vpslld $1, %xmm0, %xmm0
-; AVX2-SLOW-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX2-SLOW-NEXT:    vpblendw {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3,4,5,6,7]
-; AVX2-SLOW-NEXT:    vpshuflw {{.*#+}} xmm0 = xmm0[0,0,0,0,4,5,6,7]
-; AVX2-SLOW-NEXT:    retq
+; SSE-LABEL: PR141475:
+; SSE:       # %bb.0:
+; SSE-NEXT:    movd %edi, %xmm0
+; SSE-NEXT:    pslld $1, %xmm0
+; SSE-NEXT:    pshuflw {{.*#+}} xmm0 = xmm0[0,0,0,0,4,5,6,7]
+; SSE-NEXT:    retq
 ;
-; AVX2-FAST-LABEL: PR141475:
-; AVX2-FAST:       # %bb.0:
-; AVX2-FAST-NEXT:    vmovd %edi, %xmm0
-; AVX2-FAST-NEXT:    vpslld $1, %xmm0, %xmm0
-; AVX2-FAST-NEXT:    vpshufb {{.*#+}} xmm0 = xmm0[0,1,0,1,0,1,0,1],zero,zero,zero,zero,zero,zero,zero,zero
-; AVX2-FAST-NEXT:    retq
+; AVX-LABEL: PR141475:
+; AVX:       # %bb.0:
+; AVX-NEXT:    vmovd %edi, %xmm0
+; AVX-NEXT:    vpslld $1, %xmm0, %xmm0
+; AVX-NEXT:    vpshuflw {{.*#+}} xmm0 = xmm0[0,0,0,0,4,5,6,7]
+; AVX-NEXT:    retq
   %mul = shl i32 %in, 1
   %vecinit = insertelement <4 x i32> zeroinitializer, i32 %mul, i64 0
   %cast = bitcast <4 x i32> %vecinit to <8 x i16>