Index: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
===================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7331,6 +7331,36 @@
       AddToWorklist(Add.getNode());
       return DAG.getNode(ISD::XOR, DL, VT, Add, Shift);
     }
+
+    // If this select has a condition (setcc) with narrower operands than the
+    // select, try to widen the compare to match the select width.
+    // TODO: This should be extended to handle any constant.
+    // TODO: This could be extended to handle non-loading patterns, but that
+    //       requires thorough testing to avoid regressions.
+    if (isNullConstantOrNullSplatConstant(RHS)) {
+      EVT NarrowVT = LHS.getValueType();
+      EVT WideVT = N1.getValueType().changeVectorElementTypeToInteger();
+      EVT SetCCVT = getSetCCResultType(LHS.getValueType());
+      unsigned SetCCWidth = SetCCVT.getScalarSizeInBits();
+      unsigned WideWidth = WideVT.getScalarSizeInBits();
+      bool IsSigned = isSignedIntSetCC(CC);
+      auto LoadExtOpcode = IsSigned ? ISD::SEXTLOAD : ISD::ZEXTLOAD;
+      if (LHS.getOpcode() == ISD::LOAD && LHS.hasOneUse() &&
+          SetCCWidth != 1 && SetCCWidth < WideWidth &&
+          TLI.isLoadExtLegalOrCustom(LoadExtOpcode, WideVT, NarrowVT) &&
+          TLI.isOperationLegalOrCustom(ISD::SETCC, WideVT)) {
+        // Both compare operands can be widened for free. The LHS can use an
+        // extended load, and the RHS is a constant:
+        //   vselect (ext (setcc load(X), C)), N1, N2 -->
+        //   vselect (setcc extload(X), C'), N1, N2
+        auto ExtOpcode = IsSigned ? ISD::SIGN_EXTEND : ISD::ZERO_EXTEND;
+        SDValue WideLHS = DAG.getNode(ExtOpcode, DL, WideVT, LHS);
+        SDValue WideRHS = DAG.getNode(ExtOpcode, DL, WideVT, RHS);
+        EVT WideSetCCVT = getSetCCResultType(WideVT);
+        SDValue WideSetCC = DAG.getSetCC(DL, WideSetCCVT, WideLHS, WideRHS, CC);
+        return DAG.getSelect(DL, N1.getValueType(), WideSetCC, N1, N2);
+      }
+    }
   }
 
   if (SimplifySelectOps(N, N1, N2))
Index: llvm/trunk/test/CodeGen/X86/vsel-cmp-load.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/vsel-cmp-load.ll
+++ llvm/trunk/test/CodeGen/X86/vsel-cmp-load.ll
@@ -21,11 +21,9 @@
 ;
 ; AVX2-LABEL: eq_zero:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vpmovzxbw {{.*#+}} xmm2 = mem[0],zero,mem[1],zero,mem[2],zero,mem[3],zero,mem[4],zero,mem[5],zero,mem[6],zero,mem[7],zero
+; AVX2-NEXT:    vpmovzxbd {{.*#+}} ymm2 = mem[0],zero,zero,zero,mem[1],zero,zero,zero,mem[2],zero,zero,zero,mem[3],zero,zero,zero,mem[4],zero,zero,zero,mem[5],zero,zero,zero,mem[6],zero,zero,zero,mem[7],zero,zero,zero
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpeqw %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpmovzxwd {{.*#+}} ymm2 = xmm2[0],zero,xmm2[1],zero,xmm2[2],zero,xmm2[3],zero,xmm2[4],zero,xmm2[5],zero,xmm2[6],zero,xmm2[7],zero
-; AVX2-NEXT:    vpslld $24, %ymm2, %ymm2
+; AVX2-NEXT:    vpcmpeqd %ymm3, %ymm2, %ymm2
 ; AVX2-NEXT:    vblendvps %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -58,12 +56,11 @@
 ;
 ; AVX2-LABEL: ne_zero:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vpmovzxwd {{.*#+}} xmm2 = mem[0],zero,mem[1],zero,mem[2],zero,mem[3],zero
+; AVX2-NEXT:    vpmovzxwq {{.*#+}} ymm2 = mem[0],zero,zero,zero,mem[1],zero,zero,zero,mem[2],zero,zero,zero,mem[3],zero,zero,zero
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpeqd %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpxor %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpmovsxdq %xmm2, %ymm2
+; AVX2-NEXT:    vpcmpeqq %ymm3, %ymm2, %ymm2
+; AVX2-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX2-NEXT:    vpxor %ymm3, %ymm2, %ymm2
 ; AVX2-NEXT:    vblendvpd %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -96,10 +93,9 @@
 ;
 ; AVX2-LABEL: sgt_zero:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vmovdqa (%rdi), %xmm2
+; AVX2-NEXT:    vpmovsxbw (%rdi), %ymm2
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpgtb %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpmovsxbw %xmm2, %ymm2
+; AVX2-NEXT:    vpcmpgtw %ymm3, %ymm2, %ymm2
 ; AVX2-NEXT:    vpblendvb %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -119,23 +115,21 @@
 ; AVX1-LABEL: slt_zero:
 ; AVX1:       # %bb.0:
 ; AVX1-NEXT:    vpmovsxbw (%rdi), %xmm2
-; AVX1-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX1-NEXT:    vpcmpgtw %xmm2, %xmm3, %xmm2
-; AVX1-NEXT:    vpmovzxwd {{.*#+}} xmm3 = xmm2[0],zero,xmm2[1],zero,xmm2[2],zero,xmm2[3],zero
-; AVX1-NEXT:    vpslld $24, %xmm3, %xmm3
-; AVX1-NEXT:    vpunpckhwd {{.*#+}} xmm2 = xmm2[4],xmm0[4],xmm2[5],xmm0[5],xmm2[6],xmm0[6],xmm2[7],xmm0[7]
-; AVX1-NEXT:    vpslld $24, %xmm2, %xmm2
+; AVX1-NEXT:    vpmovsxwd %xmm2, %xmm3
+; AVX1-NEXT:    vpshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
+; AVX1-NEXT:    vpmovsxwd %xmm2, %xmm2
+; AVX1-NEXT:    vpxor %xmm4, %xmm4, %xmm4
+; AVX1-NEXT:    vpcmpgtd %xmm2, %xmm4, %xmm2
+; AVX1-NEXT:    vpcmpgtd %xmm3, %xmm4, %xmm3
 ; AVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm3, %ymm2
 ; AVX1-NEXT:    vblendvps %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: slt_zero:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vpmovsxbw (%rdi), %xmm2
+; AVX2-NEXT:    vpmovsxbd (%rdi), %ymm2
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpgtw %xmm2, %xmm3, %xmm2
-; AVX2-NEXT:    vpmovzxwd {{.*#+}} ymm2 = xmm2[0],zero,xmm2[1],zero,xmm2[2],zero,xmm2[3],zero,xmm2[4],zero,xmm2[5],zero,xmm2[6],zero,xmm2[7],zero
-; AVX2-NEXT:    vpslld $24, %ymm2, %ymm2
+; AVX2-NEXT:    vpcmpgtd %ymm2, %ymm3, %ymm2
 ; AVX2-NEXT:    vblendvps %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -166,10 +160,9 @@
 ;
 ; AVX2-LABEL: eq_zero_fp_select:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vpmovzxbd {{.*#+}} xmm2 = mem[0],zero,zero,zero,mem[1],zero,zero,zero,mem[2],zero,zero,zero,mem[3],zero,zero,zero
+; AVX2-NEXT:    vpmovzxbq {{.*#+}} ymm2 = mem[0],zero,zero,zero,zero,zero,zero,zero,mem[1],zero,zero,zero,zero,zero,zero,zero,mem[2],zero,zero,zero,zero,zero,zero,zero,mem[3],zero,zero,zero,zero,zero,zero,zero
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpeqd %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpmovsxdq %xmm2, %ymm2
+; AVX2-NEXT:    vpcmpeqq %ymm3, %ymm2, %ymm2
 ; AVX2-NEXT:    vblendvpd %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -203,13 +196,11 @@
 ;
 ; AVX2-LABEL: ne_zero_fp_select:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vpmovzxbw {{.*#+}} xmm2 = mem[0],zero,mem[1],zero,mem[2],zero,mem[3],zero,mem[4],zero,mem[5],zero,mem[6],zero,mem[7],zero
+; AVX2-NEXT:    vpmovzxbd {{.*#+}} ymm2 = mem[0],zero,zero,zero,mem[1],zero,zero,zero,mem[2],zero,zero,zero,mem[3],zero,zero,zero,mem[4],zero,zero,zero,mem[5],zero,zero,zero,mem[6],zero,zero,zero,mem[7],zero,zero,zero
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpeqw %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpxor %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpmovzxwd {{.*#+}} ymm2 = xmm2[0],zero,xmm2[1],zero,xmm2[2],zero,xmm2[3],zero,xmm2[4],zero,xmm2[5],zero,xmm2[6],zero,xmm2[7],zero
-; AVX2-NEXT:    vpslld $24, %ymm2, %ymm2
+; AVX2-NEXT:    vpcmpeqd %ymm3, %ymm2, %ymm2
+; AVX2-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX2-NEXT:    vpxor %ymm3, %ymm2, %ymm2
 ; AVX2-NEXT:    vblendvps %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -229,21 +220,21 @@
 ; AVX1-LABEL: sgt_zero_fp_select:
 ; AVX1:       # %bb.0:
 ; AVX1-NEXT:    vpmovsxbd (%rdi), %xmm2
-; AVX1-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX1-NEXT:    vpcmpgtd %xmm3, %xmm2, %xmm2
 ; AVX1-NEXT:    vpmovsxdq %xmm2, %xmm3
 ; AVX1-NEXT:    vpshufd {{.*#+}} xmm2 = xmm2[2,3,0,1]
 ; AVX1-NEXT:    vpmovsxdq %xmm2, %xmm2
+; AVX1-NEXT:    vpxor %xmm4, %xmm4, %xmm4
+; AVX1-NEXT:    vpcmpgtq %xmm4, %xmm2, %xmm2
+; AVX1-NEXT:    vpcmpgtq %xmm4, %xmm3, %xmm3
 ; AVX1-NEXT:    vinsertf128 $1, %xmm2, %ymm3, %ymm2
 ; AVX1-NEXT:    vblendvpd %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX1-NEXT:    retq
 ;
 ; AVX2-LABEL: sgt_zero_fp_select:
 ; AVX2:       # %bb.0:
-; AVX2-NEXT:    vpmovsxbd (%rdi), %xmm2
+; AVX2-NEXT:    vpmovsxbq (%rdi), %ymm2
 ; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
-; AVX2-NEXT:    vpcmpgtd %xmm3, %xmm2, %xmm2
-; AVX2-NEXT:    vpmovsxdq %xmm2, %ymm2
+; AVX2-NEXT:    vpcmpgtq %ymm3, %ymm2, %ymm2
 ; AVX2-NEXT:    vblendvpd %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;
@@ -260,6 +251,8 @@
   ret <4 x double> %sel
 }
 
+; FIXME: The compare with 0 for AVX2 should be eliminated.
+
 define <8 x float> @slt_zero_fp_select(<8 x i16>* %p, <8 x float> %x, <8 x float> %y) {
 ; AVX1-LABEL: slt_zero_fp_select:
 ; AVX1:       # %bb.0:
@@ -272,6 +265,8 @@
 ; AVX2-LABEL: slt_zero_fp_select:
 ; AVX2:       # %bb.0:
 ; AVX2-NEXT:    vpmovsxwd (%rdi), %ymm2
+; AVX2-NEXT:    vpxor %xmm3, %xmm3, %xmm3
+; AVX2-NEXT:    vpcmpgtd %ymm2, %ymm3, %ymm2
 ; AVX2-NEXT:    vblendvps %ymm2, %ymm0, %ymm1, %ymm0
 ; AVX2-NEXT:    retq
 ;