[llvm] [RFC][WIP][X86] Attempt to move the AVX512 VSELECT(COND, 0, X) -> VSELECT(!COND, X, 0) fold to DAGToDAG (PR #145724)

Simon Pilgrim via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 26 00:25:58 PDT 2025


https://github.com/RKSimon updated https://github.com/llvm/llvm-project/pull/145724

>From a9928055f4feb39f11c9227b25e8bb97ede2edc3 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Wed, 25 Jun 2025 16:44:45 +0100
Subject: [PATCH 1/2] [RFC][WIP][X86] Attempt to move the AVX512 VSELECT(COND,
 0, X) -> VSELECT(!COND, X, 0) fold to DAGToDAG

Initial attempt to remove the fold out of ISel to avoid regressions identified in #145473

It still doesn't handle predicate widening which might not be very pretty......
---
 llvm/lib/Target/X86/X86ISelDAGToDAG.cpp       |  59 ++++--
 llvm/lib/Target/X86/X86ISelLowering.cpp       |  32 ++--
 .../test/CodeGen/X86/extract-vselect-setcc.ll |   3 +-
 llvm/test/CodeGen/X86/psubus.ll               |   4 +-
 llvm/test/CodeGen/X86/var-permute-128.ll      | 128 ++++++-------
 llvm/test/CodeGen/X86/var-permute-256.ll      | 170 +++++++++---------
 6 files changed, 217 insertions(+), 179 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 32c7d2bfea6c2..768f033356959 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1139,24 +1139,51 @@ void X86DAGToDAGISel::PreprocessISelDAG() {
       break;
     }
     case ISD::VSELECT: {
-      // Replace VSELECT with non-mask conditions with with BLENDV/VPTERNLOG.
-      EVT EleVT = N->getOperand(0).getValueType().getVectorElementType();
-      if (EleVT == MVT::i1)
-        break;
-
-      assert(Subtarget->hasSSE41() && "Expected SSE4.1 support!");
-      assert(N->getValueType(0).getVectorElementType() != MVT::i16 &&
-             "We can't replace VSELECT with BLENDV in vXi16!");
+      SDValue Cond = N->getOperand(0);
+      SDValue LHS = N->getOperand(1);
+      SDValue RHS = N->getOperand(2);
+      EVT CondVT = Cond.getValueType();
+      EVT EleVT = CondVT.getVectorElementType();
       SDValue R;
-      if (Subtarget->hasVLX() && CurDAG->ComputeNumSignBits(N->getOperand(0)) ==
-                                     EleVT.getSizeInBits()) {
-        R = CurDAG->getNode(X86ISD::VPTERNLOG, SDLoc(N), N->getValueType(0),
-                            N->getOperand(0), N->getOperand(1), N->getOperand(2),
-                            CurDAG->getTargetConstant(0xCA, SDLoc(N), MVT::i8));
+
+      if (EleVT == MVT::i1) {
+        assert(Subtarget->hasAVX512() && "Expected AVX512 support!");
+        if (!ISD::isBuildVectorAllZeros(LHS.getNode()) ||
+            ISD::isBuildVectorAllZeros(RHS.getNode()))
+          break;
+        // If this an avx512 target we can improve the use of zero masking by
+        // swapping the operands and inverting the condition.
+        // vselect cond, op1, op2 = vselect not(cond), op2, op1
+        if (Cond.getOpcode() == ISD::SETCC &&
+            !ISD::isBuildVectorAllZeros(Cond.getOperand(0).getNode())) {
+          ISD::CondCode CC = cast<CondCodeSDNode>(Cond.getOperand(2))->get();
+          CC = ISD::getSetCCInverse(CC, Cond.getOperand(0).getValueType());
+          R = CurDAG->getSetCC(SDLoc(N), CondVT, Cond.getOperand(0),
+                               Cond.getOperand(1), CC);
+        } else if (Cond.getOpcode() == X86ISD::CMPM &&
+                   Cond.getConstantOperandVal(2) == 0) {
+          // FLIP FCMP EQ -> (U)NE
+          R = CurDAG->getNode(Cond.getOpcode(), SDLoc(N), CondVT,
+                              Cond.getOperand(0), Cond.getOperand(1),
+                              CurDAG->getTargetConstant(4, SDLoc(N), MVT::i8));
+        } else {
+          R = CurDAG->getNOT(SDLoc(N), Cond, CondVT);
+        }
+        R = CurDAG->getSelect(SDLoc(N), N->getValueType(0), R, RHS, LHS);
       } else {
-        R = CurDAG->getNode(X86ISD::BLENDV, SDLoc(N), N->getValueType(0),
-                            N->getOperand(0), N->getOperand(1),
-                            N->getOperand(2));
+        // Replace VSELECT with non-mask conditions with BLENDV/VPTERNLOG.
+        assert(Subtarget->hasSSE41() && "Expected SSE4.1 support!");
+        assert(N->getValueType(0).getVectorElementType() != MVT::i16 &&
+               "We can't replace VSELECT with BLENDV in vXi16!");
+        if (Subtarget->hasVLX() &&
+            CurDAG->ComputeNumSignBits(Cond) == EleVT.getSizeInBits()) {
+          R = CurDAG->getNode(
+              X86ISD::VPTERNLOG, SDLoc(N), N->getValueType(0), Cond, LHS, RHS,
+              CurDAG->getTargetConstant(0xCA, SDLoc(N), MVT::i8));
+        } else {
+          R = CurDAG->getNode(X86ISD::BLENDV, SDLoc(N), N->getValueType(0),
+                              Cond, LHS, RHS);
+        }
       }
       --I;
       CurDAG->ReplaceAllUsesWith(N, R.getNode());
diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 7c26dd6e2dc2f..da1f48ede5402 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -5415,6 +5415,20 @@ static SDValue IsNOT(SDValue V, SelectionDAG &DAG) {
     }
   }
 
+  // Match not(insert_subvector(undef, setcc(), c))
+  // --> insert_subvector(undef, not(setcc()), c)
+  if (V.getOpcode() == ISD::INSERT_SUBVECTOR && V.getOperand(0).isUndef() &&
+      V.getOperand(1).getOpcode() == ISD::SETCC &&
+      V.getValueType().getScalarType() == MVT::i1) {
+    SDValue Cond = V.getOperand(1);
+    ISD::CondCode CC = cast<CondCodeSDNode>(Cond.getOperand(2))->get();
+    CC = ISD::getSetCCInverse(CC, Cond.getOperand(0).getValueType());
+    SDValue NotSub = DAG.getSetCC(SDLoc(Cond), Cond.getValueType(),
+                                  Cond.getOperand(0), Cond.getOperand(1), CC);
+    return DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(V), V.getValueType(),
+                       V.getOperand(0), NotSub, V.getOperand(2));
+  }
+
   // Match not(concat_vectors(not(X), not(Y))) -> concat_vectors(X, Y).
   SmallVector<SDValue, 2> CatOps;
   if (collectConcatOps(V.getNode(), CatOps, DAG)) {
@@ -48049,19 +48063,6 @@ static SDValue combineSelect(SDNode *N, SelectionDAG &DAG,
     }
   }
 
-  // Check if the first operand is all zeros and Cond type is vXi1.
-  // If this an avx512 target we can improve the use of zero masking by
-  // swapping the operands and inverting the condition.
-  if (N->getOpcode() == ISD::VSELECT && Cond.hasOneUse() &&
-      Subtarget.hasAVX512() && CondVT.getVectorElementType() == MVT::i1 &&
-      ISD::isBuildVectorAllZeros(LHS.getNode()) &&
-      !ISD::isBuildVectorAllZeros(RHS.getNode())) {
-    // Invert the cond to not(cond) : xor(op,allones)=not(op)
-    SDValue CondNew = DAG.getNOT(DL, Cond, CondVT);
-    // Vselect cond, op1, op2 = Vselect not(cond), op2, op1
-    return DAG.getSelect(DL, VT, CondNew, RHS, LHS);
-  }
-
   // Attempt to convert a (vXi1 bitcast(iX Cond)) selection mask before it might
   // get split by legalization.
   if (N->getOpcode() == ISD::VSELECT && Cond.getOpcode() == ISD::BITCAST &&
@@ -48125,11 +48126,14 @@ static SDValue combineSelect(SDNode *N, SelectionDAG &DAG,
     return V;
 
   // select(~Cond, X, Y) -> select(Cond, Y, X)
-  if (CondVT.getScalarType() != MVT::i1) {
+  if (CondVT.getScalarType() != MVT::i1 ||
+      (ISD::isBuildVectorAllZeros(LHS.getNode()) &&
+       !ISD::isBuildVectorAllZeros(RHS.getNode())))
     if (SDValue CondNot = IsNOT(Cond, DAG))
       return DAG.getNode(N->getOpcode(), DL, VT,
                          DAG.getBitcast(CondVT, CondNot), RHS, LHS);
 
+  if (CondVT.getScalarType() != MVT::i1) {
     // select(pcmpeq(and(X,Pow2),0),A,B) -> select(pcmpeq(and(X,Pow2),Pow2),B,A)
     if (Cond.getOpcode() == X86ISD::PCMPEQ &&
         Cond.getOperand(0).getOpcode() == ISD::AND &&
diff --git a/llvm/test/CodeGen/X86/extract-vselect-setcc.ll b/llvm/test/CodeGen/X86/extract-vselect-setcc.ll
index 96c8e773d5edd..1997323ed61a6 100644
--- a/llvm/test/CodeGen/X86/extract-vselect-setcc.ll
+++ b/llvm/test/CodeGen/X86/extract-vselect-setcc.ll
@@ -5,7 +5,8 @@ define void @PR117684(i1 %cond, <8 x float> %vec, ptr %ptr1, ptr %ptr2) #0 {
 ; CHECK-LABEL: PR117684:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; CHECK-NEXT:    vcmpnltss %xmm1, %xmm0, %k1
+; CHECK-NEXT:    vcmpltss %xmm1, %xmm0, %k0
+; CHECK-NEXT:    knotb %k0, %k1
 ; CHECK-NEXT:    vbroadcastss {{.*#+}} xmm0 = [NaN,NaN,NaN,NaN]
 ; CHECK-NEXT:    vinsertf32x4 $0, %xmm0, %ymm0, %ymm0 {%k1} {z}
 ; CHECK-NEXT:    vmulss %xmm1, %xmm0, %xmm0
diff --git a/llvm/test/CodeGen/X86/psubus.ll b/llvm/test/CodeGen/X86/psubus.ll
index e10b360b35b56..cc3aee4feba2d 100644
--- a/llvm/test/CodeGen/X86/psubus.ll
+++ b/llvm/test/CodeGen/X86/psubus.ll
@@ -981,9 +981,9 @@ define <16 x i8> @test14(<16 x i8> %x, <16 x i32> %y) nounwind {
 ; AVX512-LABEL: test14:
 ; AVX512:       # %bb.0: # %vector.ph
 ; AVX512-NEXT:    vpmovzxbd {{.*#+}} zmm2 = xmm0[0],zero,zero,zero,xmm0[1],zero,zero,zero,xmm0[2],zero,zero,zero,xmm0[3],zero,zero,zero,xmm0[4],zero,zero,zero,xmm0[5],zero,zero,zero,xmm0[6],zero,zero,zero,xmm0[7],zero,zero,zero,xmm0[8],zero,zero,zero,xmm0[9],zero,zero,zero,xmm0[10],zero,zero,zero,xmm0[11],zero,zero,zero,xmm0[12],zero,zero,zero,xmm0[13],zero,zero,zero,xmm0[14],zero,zero,zero,xmm0[15],zero,zero,zero
+; AVX512-NEXT:    vpmovdb %zmm1, %xmm3
 ; AVX512-NEXT:    vpcmpnltud %zmm2, %zmm1, %k1
-; AVX512-NEXT:    vpmovdb %zmm1, %xmm1
-; AVX512-NEXT:    vpsubb %xmm0, %xmm1, %xmm0 {%k1} {z}
+; AVX512-NEXT:    vpsubb %xmm0, %xmm3, %xmm0 {%k1} {z}
 ; AVX512-NEXT:    vzeroupper
 ; AVX512-NEXT:    retq
 vector.ph:
diff --git a/llvm/test/CodeGen/X86/var-permute-128.ll b/llvm/test/CodeGen/X86/var-permute-128.ll
index 7f4111e65cc17..067d4c569d276 100644
--- a/llvm/test/CodeGen/X86/var-permute-128.ll
+++ b/llvm/test/CodeGen/X86/var-permute-128.ll
@@ -170,25 +170,26 @@ define <2 x i64> @var_shuffle_zero_v2i64(<2 x i64> %v, <2 x i64> %indices) nounw
 ; AVX512-NEXT:    # kill: def $xmm1 killed $xmm1 def $zmm1
 ; AVX512-NEXT:    vpmovsxbq {{.*#+}} xmm2 = [3,3]
 ; AVX512-NEXT:    vpcmpnleuq %zmm2, %zmm1, %k1
-; AVX512-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512-NEXT:    vmovdqa64 %zmm2, %zmm1 {%k1}
-; AVX512-NEXT:    vpaddq %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vpermilpd %xmm1, %xmm0, %xmm0
-; AVX512-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vmovdqa64 %zmm1, %zmm0 {%k1}
+; AVX512-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512-NEXT:    vpblendmq %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512-NEXT:    vpaddq %xmm3, %xmm3, %xmm3
+; AVX512-NEXT:    vpermilpd %xmm3, %xmm0, %xmm0
+; AVX512-NEXT:    vpcmpleuq %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vmovdqa64 %zmm0, %zmm0 {%k1} {z}
 ; AVX512-NEXT:    # kill: def $xmm0 killed $xmm0 killed $zmm0
 ; AVX512-NEXT:    vzeroupper
 ; AVX512-NEXT:    retq
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v2i64:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleuq {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to2}, %xmm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512VL-NEXT:    vmovdqa64 %xmm2, %xmm1 {%k1}
-; AVX512VL-NEXT:    vpaddq %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vpermilpd %xmm1, %xmm0, %xmm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovdqa64 %xmm1, %xmm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastq {{.*#+}} xmm2 = [3,3]
+; AVX512VL-NEXT:    vpcmpnleuq %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpblendmq %xmm3, %xmm1, %xmm3 {%k1}
+; AVX512VL-NEXT:    vpaddq %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpermilpd %xmm3, %xmm0, %xmm0
+; AVX512VL-NEXT:    vpcmpleuq %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vmovdqa64 %xmm0, %xmm0 {%k1} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <2 x i64> %indices, <i64 3, i64 3>
   %or = select <2 x i1> %cmp, <2 x i64> <i64 -1, i64 -1>, <2 x i64> %indices
@@ -355,24 +356,26 @@ define <4 x i32> @var_shuffle_zero_v4i32(<4 x i32> %v, <4 x i32> %indices) nounw
 ; AVX512-LABEL: var_shuffle_zero_v4i32:
 ; AVX512:       # %bb.0:
 ; AVX512-NEXT:    # kill: def $xmm1 killed $xmm1 def $zmm1
-; AVX512-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm1, %k1
-; AVX512-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512-NEXT:    vmovdqa32 %zmm2, %zmm1 {%k1}
-; AVX512-NEXT:    vpermilps %xmm1, %xmm0, %xmm0
-; AVX512-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vmovdqa32 %zmm1, %zmm0 {%k1}
+; AVX512-NEXT:    vpbroadcastd {{.*#+}} xmm2 = [3,3,3,3]
+; AVX512-NEXT:    vpcmpnleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512-NEXT:    vpblendmd %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512-NEXT:    vpermilps %xmm3, %xmm0, %xmm0
+; AVX512-NEXT:    vpcmpleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vmovdqa32 %zmm0, %zmm0 {%k1} {z}
 ; AVX512-NEXT:    # kill: def $xmm0 killed $xmm0 killed $zmm0
 ; AVX512-NEXT:    vzeroupper
 ; AVX512-NEXT:    retq
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v4i32:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to4}, %xmm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512VL-NEXT:    vmovdqa32 %xmm2, %xmm1 {%k1}
-; AVX512VL-NEXT:    vpermilps %xmm1, %xmm0, %xmm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovdqa32 %xmm1, %xmm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastd {{.*#+}} xmm2 = [3,3,3,3]
+; AVX512VL-NEXT:    vpcmpnleud %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpblendmd %xmm3, %xmm1, %xmm3 {%k1}
+; AVX512VL-NEXT:    vpermilps %xmm3, %xmm0, %xmm0
+; AVX512VL-NEXT:    vpcmpleud %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vmovdqa32 %xmm0, %xmm0 {%k1} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <4 x i32> %indices, <i32 3, i32 3, i32 3, i32 3>
   %or = select <4 x i1> %cmp, <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>, <4 x i32> %indices
@@ -600,12 +603,12 @@ define <8 x i16> @var_shuffle_zero_v8i16(<8 x i16> %v, <8 x i16> %indices) nounw
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v8i16:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleuw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512VL-NEXT:    vmovdqu16 %xmm2, %xmm1 {%k1}
-; AVX512VL-NEXT:    vpermw %xmm0, %xmm1, %xmm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovdqu16 %xmm1, %xmm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastw {{.*#+}} xmm2 = [7,7,7,7,7,7,7,7]
+; AVX512VL-NEXT:    vpcmpnleuw %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpcmpleuw %xmm2, %xmm1, %k2
+; AVX512VL-NEXT:    vmovdqu16 %xmm3, %xmm1 {%k1}
+; AVX512VL-NEXT:    vpermw %xmm0, %xmm1, %xmm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <8 x i16> %indices, <i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7, i16 7>
   %or = select <8 x i1> %cmp, <8 x i16> <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>, <8 x i16> %indices
@@ -923,12 +926,12 @@ define <16 x i8> @var_shuffle_zero_v16i8(<16 x i8> %v, <16 x i8> %indices) nounw
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v16i8:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleub {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512VL-NEXT:    vmovdqu8 %xmm2, %xmm1 {%k1}
-; AVX512VL-NEXT:    vpshufb %xmm1, %xmm0, %xmm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovdqu8 %xmm1, %xmm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastb {{.*#+}} xmm2 = [15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15]
+; AVX512VL-NEXT:    vpcmpnleub %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpcmpleub %xmm2, %xmm1, %k2
+; AVX512VL-NEXT:    vmovdqu8 %xmm3, %xmm1 {%k1}
+; AVX512VL-NEXT:    vpshufb %xmm1, %xmm0, %xmm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <16 x i8> %indices, <i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15, i8 15>
   %or = select <16 x i1> %cmp, <16 x i8> <i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1>, <16 x i8> %indices
@@ -1139,25 +1142,25 @@ define <2 x double> @var_shuffle_zero_v2f64(<2 x double> %v, <2 x i64> %indices)
 ; AVX512-NEXT:    # kill: def $xmm1 killed $xmm1 def $zmm1
 ; AVX512-NEXT:    vpmovsxbq {{.*#+}} xmm2 = [3,3]
 ; AVX512-NEXT:    vpcmpnleuq %zmm2, %zmm1, %k1
-; AVX512-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512-NEXT:    vmovdqa64 %zmm2, %zmm1 {%k1}
-; AVX512-NEXT:    vpaddq %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vpermilpd %xmm1, %xmm0, %xmm0
-; AVX512-NEXT:    vxorpd %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vmovapd %zmm1, %zmm0 {%k1}
+; AVX512-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512-NEXT:    vpblendmq %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512-NEXT:    vpaddq %xmm3, %xmm3, %xmm3
+; AVX512-NEXT:    vpermilpd %xmm3, %xmm0, %xmm0
+; AVX512-NEXT:    vpcmpleuq %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vmovapd %zmm0, %zmm0 {%k1} {z}
 ; AVX512-NEXT:    # kill: def $xmm0 killed $xmm0 killed $zmm0
 ; AVX512-NEXT:    vzeroupper
 ; AVX512-NEXT:    retq
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v2f64:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleuq {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to2}, %xmm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512VL-NEXT:    vmovdqa64 %xmm2, %xmm1 {%k1}
-; AVX512VL-NEXT:    vpaddq %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vpermilpd %xmm1, %xmm0, %xmm0
-; AVX512VL-NEXT:    vxorpd %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovapd %xmm1, %xmm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastq {{.*#+}} xmm2 = [3,3]
+; AVX512VL-NEXT:    vpcmpnleuq %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpblendmq %xmm3, %xmm1, %xmm3 {%k1}
+; AVX512VL-NEXT:    vpaddq %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpcmpleuq %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpermilpd %xmm3, %xmm0, %xmm0 {%k1} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <2 x i64> %indices, <i64 3, i64 3>
   %or = select <2 x i1> %cmp, <2 x i64> <i64 -1, i64 -1>, <2 x i64> %indices
@@ -1324,24 +1327,25 @@ define <4 x float> @var_shuffle_zero_v4f32(<4 x float> %v, <4 x i32> %indices) n
 ; AVX512-LABEL: var_shuffle_zero_v4f32:
 ; AVX512:       # %bb.0:
 ; AVX512-NEXT:    # kill: def $xmm1 killed $xmm1 def $zmm1
-; AVX512-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm1, %k1
-; AVX512-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512-NEXT:    vmovdqa32 %zmm2, %zmm1 {%k1}
-; AVX512-NEXT:    vpermilps %xmm1, %xmm0, %xmm0
-; AVX512-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vmovaps %zmm1, %zmm0 {%k1}
+; AVX512-NEXT:    vpbroadcastd {{.*#+}} xmm2 = [3,3,3,3]
+; AVX512-NEXT:    vpcmpnleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512-NEXT:    vpblendmd %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512-NEXT:    vpermilps %xmm3, %xmm0, %xmm0
+; AVX512-NEXT:    vpcmpleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vmovaps %zmm0, %zmm0 {%k1} {z}
 ; AVX512-NEXT:    # kill: def $xmm0 killed $xmm0 killed $zmm0
 ; AVX512-NEXT:    vzeroupper
 ; AVX512-NEXT:    retq
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v4f32:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to4}, %xmm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %xmm2, %xmm2, %xmm2
-; AVX512VL-NEXT:    vmovdqa32 %xmm2, %xmm1 {%k1}
-; AVX512VL-NEXT:    vpermilps %xmm1, %xmm0, %xmm0
-; AVX512VL-NEXT:    vxorps %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovaps %xmm1, %xmm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastd {{.*#+}} xmm2 = [3,3,3,3]
+; AVX512VL-NEXT:    vpcmpnleud %xmm2, %xmm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %xmm3, %xmm3, %xmm3
+; AVX512VL-NEXT:    vpcmpleud %xmm2, %xmm1, %k2
+; AVX512VL-NEXT:    vmovdqa32 %xmm3, %xmm1 {%k1}
+; AVX512VL-NEXT:    vpermilps %xmm1, %xmm0, %xmm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <4 x i32> %indices, <i32 3, i32 3, i32 3, i32 3>
   %or = select <4 x i1> %cmp, <4 x i32> <i32 -1, i32 -1, i32 -1, i32 -1>, <4 x i32> %indices
diff --git a/llvm/test/CodeGen/X86/var-permute-256.ll b/llvm/test/CodeGen/X86/var-permute-256.ll
index 283c6a303a581..6a450e2665171 100644
--- a/llvm/test/CodeGen/X86/var-permute-256.ll
+++ b/llvm/test/CodeGen/X86/var-permute-256.ll
@@ -158,12 +158,12 @@ define <4 x i64> @var_shuffle_zero_v4i64(<4 x i64> %v, <4 x i64> %indices) nounw
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v4i64:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleuq {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to4}, %ymm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512VL-NEXT:    vmovdqa64 %ymm2, %ymm1 {%k1}
-; AVX512VL-NEXT:    vpermq %ymm0, %ymm1, %ymm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovdqa64 %ymm1, %ymm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastq {{.*#+}} ymm2 = [3,3,3,3]
+; AVX512VL-NEXT:    vpcmpnleuq %ymm2, %ymm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512VL-NEXT:    vpcmpleuq %ymm2, %ymm1, %k2
+; AVX512VL-NEXT:    vmovdqa64 %ymm3, %ymm1 {%k1}
+; AVX512VL-NEXT:    vpermq %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <4 x i64> %indices, <i64 3, i64 3, i64 3, i64 3>
   %or = select <4 x i1> %cmp, <4 x i64> <i64 -1, i64 -1, i64 -1, i64 -1>, <4 x i64> %indices
@@ -285,23 +285,24 @@ define <8 x i32> @var_shuffle_zero_v8i32(<8 x i32> %v, <8 x i32> %indices) nounw
 ; AVX512-LABEL: var_shuffle_zero_v8i32:
 ; AVX512:       # %bb.0:
 ; AVX512-NEXT:    # kill: def $ymm1 killed $ymm1 def $zmm1
-; AVX512-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm1, %k1
-; AVX512-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512-NEXT:    vmovdqa32 %zmm2, %zmm1 {%k1}
-; AVX512-NEXT:    vpermd %ymm0, %ymm1, %ymm0
-; AVX512-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vmovdqa32 %zmm1, %zmm0 {%k1}
+; AVX512-NEXT:    vpbroadcastd {{.*#+}} ymm2 = [7,7,7,7,7,7,7,7]
+; AVX512-NEXT:    vpcmpnleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512-NEXT:    vpblendmd %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512-NEXT:    vpermd %ymm0, %ymm3, %ymm0
+; AVX512-NEXT:    vpcmpleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vmovdqa32 %zmm0, %zmm0 {%k1} {z}
 ; AVX512-NEXT:    # kill: def $ymm0 killed $ymm0 killed $zmm0
 ; AVX512-NEXT:    retq
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v8i32:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to8}, %ymm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512VL-NEXT:    vmovdqa32 %ymm2, %ymm1 {%k1}
-; AVX512VL-NEXT:    vpermd %ymm0, %ymm1, %ymm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovdqa32 %ymm1, %ymm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastd {{.*#+}} ymm2 = [7,7,7,7,7,7,7,7]
+; AVX512VL-NEXT:    vpcmpnleud %ymm2, %ymm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512VL-NEXT:    vpcmpleud %ymm2, %ymm1, %k2
+; AVX512VL-NEXT:    vmovdqa32 %ymm3, %ymm1 {%k1}
+; AVX512VL-NEXT:    vpermd %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <8 x i32> %indices, <i32 7, i32 7, i32 7, i32 7, i32 7, i32 7, i32 7, i32 7>
   %or = select <8 x i1> %cmp, <8 x i32> <i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1>, <8 x i32> %indices
@@ -554,18 +555,18 @@ define <16 x i16> @var_shuffle_zero_v16i16(<16 x i16> %v, <16 x i16> %indices) n
 ; AVX512BW-NEXT:    # kill: def $ymm1 killed $ymm1 def $zmm1
 ; AVX512BW-NEXT:    vpbroadcastw {{.*#+}} ymm2 = [15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15]
 ; AVX512BW-NEXT:    vpcmpnleuw %zmm2, %zmm1, %k1
-; AVX512BW-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512BW-NEXT:    vmovdqu16 %zmm2, %zmm1 {%k1}
-; AVX512BW-NEXT:    vpmullw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %ymm1 # [514,514,514,514,514,514,514,514,514,514,514,514,514,514,514,514]
-; AVX512BW-NEXT:    vpaddw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %ymm1
-; AVX512BW-NEXT:    vpermq {{.*#+}} ymm2 = ymm0[2,3,2,3]
-; AVX512BW-NEXT:    vpshufb %ymm1, %ymm2, %ymm2
+; AVX512BW-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512BW-NEXT:    vpblendmw %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512BW-NEXT:    vpmullw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm3, %ymm3 # [514,514,514,514,514,514,514,514,514,514,514,514,514,514,514,514]
+; AVX512BW-NEXT:    vpaddw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm3, %ymm3
+; AVX512BW-NEXT:    vpermq {{.*#+}} ymm4 = ymm0[2,3,2,3]
+; AVX512BW-NEXT:    vpshufb %ymm3, %ymm4, %ymm4
 ; AVX512BW-NEXT:    vinserti128 $1, %xmm0, %ymm0, %ymm0
-; AVX512BW-NEXT:    vpshufb %ymm1, %ymm0, %ymm0
-; AVX512BW-NEXT:    vpcmpgtb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %ymm1
-; AVX512BW-NEXT:    vpblendvb %ymm1, %ymm2, %ymm0, %ymm0
-; AVX512BW-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512BW-NEXT:    vmovdqu16 %zmm1, %zmm0 {%k1}
+; AVX512BW-NEXT:    vpshufb %ymm3, %ymm0, %ymm0
+; AVX512BW-NEXT:    vpcmpgtb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm3, %ymm3
+; AVX512BW-NEXT:    vpblendvb %ymm3, %ymm4, %ymm0, %ymm0
+; AVX512BW-NEXT:    vpcmpleuw %zmm2, %zmm1, %k1
+; AVX512BW-NEXT:    vmovdqu16 %zmm0, %zmm0 {%k1} {z}
 ; AVX512BW-NEXT:    # kill: def $ymm0 killed $ymm0 killed $zmm0
 ; AVX512BW-NEXT:    retq
 ;
@@ -587,22 +588,22 @@ define <16 x i16> @var_shuffle_zero_v16i16(<16 x i16> %v, <16 x i16> %indices) n
 ;
 ; AVX512VLBW-LABEL: var_shuffle_zero_v16i16:
 ; AVX512VLBW:       # %bb.0:
-; AVX512VLBW-NEXT:    vpcmpnleuw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %k1
-; AVX512VLBW-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512VLBW-NEXT:    vmovdqu16 %ymm2, %ymm1 {%k1}
-; AVX512VLBW-NEXT:    vpermw %ymm0, %ymm1, %ymm0
-; AVX512VLBW-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VLBW-NEXT:    vmovdqu16 %ymm1, %ymm0 {%k1}
+; AVX512VLBW-NEXT:    vpbroadcastw {{.*#+}} ymm2 = [15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15]
+; AVX512VLBW-NEXT:    vpcmpnleuw %ymm2, %ymm1, %k1
+; AVX512VLBW-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512VLBW-NEXT:    vpcmpleuw %ymm2, %ymm1, %k2
+; AVX512VLBW-NEXT:    vmovdqu16 %ymm3, %ymm1 {%k1}
+; AVX512VLBW-NEXT:    vpermw %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; AVX512VLBW-NEXT:    retq
 ;
 ; VLVBMI-LABEL: var_shuffle_zero_v16i16:
 ; VLVBMI:       # %bb.0:
-; VLVBMI-NEXT:    vpcmpnleuw {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %k1
-; VLVBMI-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; VLVBMI-NEXT:    vmovdqu16 %ymm2, %ymm1 {%k1}
-; VLVBMI-NEXT:    vpermw %ymm0, %ymm1, %ymm0
-; VLVBMI-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; VLVBMI-NEXT:    vmovdqu16 %ymm1, %ymm0 {%k1}
+; VLVBMI-NEXT:    vpbroadcastw {{.*#+}} ymm2 = [15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15]
+; VLVBMI-NEXT:    vpcmpnleuw %ymm2, %ymm1, %k1
+; VLVBMI-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; VLVBMI-NEXT:    vpcmpleuw %ymm2, %ymm1, %k2
+; VLVBMI-NEXT:    vmovdqu16 %ymm3, %ymm1 {%k1}
+; VLVBMI-NEXT:    vpermw %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; VLVBMI-NEXT:    retq
   %cmp = icmp ugt <16 x i16> %indices, <i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15, i16 15>
   %or = select <16 x i1> %cmp, <16 x i16> <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>, <16 x i16> %indices
@@ -902,16 +903,16 @@ define <32 x i8> @var_shuffle_zero_v32i8(<32 x i8> %v, <32 x i8> %indices) nounw
 ; AVX512BW-NEXT:    # kill: def $ymm1 killed $ymm1 def $zmm1
 ; AVX512BW-NEXT:    vpbroadcastb {{.*#+}} ymm2 = [31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31]
 ; AVX512BW-NEXT:    vpcmpnleub %zmm2, %zmm1, %k1
-; AVX512BW-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512BW-NEXT:    vmovdqu8 %zmm2, %zmm1 {%k1}
-; AVX512BW-NEXT:    vpermq {{.*#+}} ymm2 = ymm0[2,3,2,3]
-; AVX512BW-NEXT:    vpshufb %ymm1, %ymm2, %ymm2
+; AVX512BW-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512BW-NEXT:    vpblendmb %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512BW-NEXT:    vpermq {{.*#+}} ymm4 = ymm0[2,3,2,3]
+; AVX512BW-NEXT:    vpshufb %ymm3, %ymm4, %ymm4
 ; AVX512BW-NEXT:    vinserti128 $1, %xmm0, %ymm0, %ymm0
-; AVX512BW-NEXT:    vpshufb %ymm1, %ymm0, %ymm0
-; AVX512BW-NEXT:    vpcmpgtb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %ymm1
-; AVX512BW-NEXT:    vpblendvb %ymm1, %ymm2, %ymm0, %ymm0
-; AVX512BW-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512BW-NEXT:    vmovdqu8 %zmm1, %zmm0 {%k1}
+; AVX512BW-NEXT:    vpshufb %ymm3, %ymm0, %ymm0
+; AVX512BW-NEXT:    vpcmpgtb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm3, %ymm3
+; AVX512BW-NEXT:    vpblendvb %ymm3, %ymm4, %ymm0, %ymm0
+; AVX512BW-NEXT:    vpcmpleub %zmm2, %zmm1, %k1
+; AVX512BW-NEXT:    vmovdqu8 %zmm0, %zmm0 {%k1} {z}
 ; AVX512BW-NEXT:    # kill: def $ymm0 killed $ymm0 killed $zmm0
 ; AVX512BW-NEXT:    retq
 ;
@@ -931,27 +932,27 @@ define <32 x i8> @var_shuffle_zero_v32i8(<32 x i8> %v, <32 x i8> %indices) nounw
 ;
 ; AVX512VLBW-LABEL: var_shuffle_zero_v32i8:
 ; AVX512VLBW:       # %bb.0:
-; AVX512VLBW-NEXT:    vpcmpnleub {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %k1
-; AVX512VLBW-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512VLBW-NEXT:    vmovdqu8 %ymm2, %ymm1 {%k1}
-; AVX512VLBW-NEXT:    vinserti128 $1, %xmm0, %ymm0, %ymm2
-; AVX512VLBW-NEXT:    vpshufb %ymm1, %ymm2, %ymm2
-; AVX512VLBW-NEXT:    vpcmpgtb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %k2
+; AVX512VLBW-NEXT:    vpbroadcastb {{.*#+}} ymm2 = [31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31]
+; AVX512VLBW-NEXT:    vpcmpnleub %ymm2, %ymm1, %k1
+; AVX512VLBW-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512VLBW-NEXT:    vpblendmb %ymm3, %ymm1, %ymm3 {%k1}
+; AVX512VLBW-NEXT:    vinserti128 $1, %xmm0, %ymm0, %ymm4
+; AVX512VLBW-NEXT:    vpshufb %ymm3, %ymm4, %ymm4
+; AVX512VLBW-NEXT:    vpcmpgtb {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm3, %k1
 ; AVX512VLBW-NEXT:    vpermq {{.*#+}} ymm0 = ymm0[2,3,2,3]
-; AVX512VLBW-NEXT:    vpshufb %ymm1, %ymm0, %ymm2 {%k2}
-; AVX512VLBW-NEXT:    vpxor %xmm0, %xmm0, %xmm0
-; AVX512VLBW-NEXT:    vmovdqu8 %ymm0, %ymm2 {%k1}
-; AVX512VLBW-NEXT:    vmovdqa %ymm2, %ymm0
+; AVX512VLBW-NEXT:    vpshufb %ymm3, %ymm0, %ymm4 {%k1}
+; AVX512VLBW-NEXT:    vpcmpleub %ymm2, %ymm1, %k1
+; AVX512VLBW-NEXT:    vmovdqu8 %ymm4, %ymm0 {%k1} {z}
 ; AVX512VLBW-NEXT:    retq
 ;
 ; VLVBMI-LABEL: var_shuffle_zero_v32i8:
 ; VLVBMI:       # %bb.0:
-; VLVBMI-NEXT:    vpcmpnleub {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %ymm1, %k1
-; VLVBMI-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; VLVBMI-NEXT:    vmovdqu8 %ymm2, %ymm1 {%k1}
-; VLVBMI-NEXT:    vpermb %ymm0, %ymm1, %ymm0
-; VLVBMI-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; VLVBMI-NEXT:    vmovdqu8 %ymm1, %ymm0 {%k1}
+; VLVBMI-NEXT:    vpbroadcastb {{.*#+}} ymm2 = [31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31,31]
+; VLVBMI-NEXT:    vpcmpnleub %ymm2, %ymm1, %k1
+; VLVBMI-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; VLVBMI-NEXT:    vpcmpleub %ymm2, %ymm1, %k2
+; VLVBMI-NEXT:    vmovdqu8 %ymm3, %ymm1 {%k1}
+; VLVBMI-NEXT:    vpermb %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; VLVBMI-NEXT:    retq
   %cmp = icmp ugt <32 x i8> %indices, <i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31, i8 31>
   %or = select <32 x i1> %cmp, <32 x i8> <i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1>, <32 x i8> %indices
@@ -1202,12 +1203,12 @@ define <4 x double> @var_shuffle_zero_v4f64(<4 x double> %v, <4 x i64> %indices)
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v4f64:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleuq {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to4}, %ymm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512VL-NEXT:    vmovdqa64 %ymm2, %ymm1 {%k1}
-; AVX512VL-NEXT:    vpermq %ymm0, %ymm1, %ymm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovapd %ymm1, %ymm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastq {{.*#+}} ymm2 = [3,3,3,3]
+; AVX512VL-NEXT:    vpcmpnleuq %ymm2, %ymm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512VL-NEXT:    vpcmpleuq %ymm2, %ymm1, %k2
+; AVX512VL-NEXT:    vmovdqa64 %ymm3, %ymm1 {%k1}
+; AVX512VL-NEXT:    vpermpd %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <4 x i64> %indices, <i64 3, i64 3, i64 3, i64 3>
   %or = select <4 x i1> %cmp, <4 x i64> <i64 -1, i64 -1, i64 -1, i64 -1>, <4 x i64> %indices
@@ -1329,23 +1330,24 @@ define <8 x float> @var_shuffle_zero_v8f32(<8 x float> %v, <8 x i32> %indices) n
 ; AVX512-LABEL: var_shuffle_zero_v8f32:
 ; AVX512:       # %bb.0:
 ; AVX512-NEXT:    # kill: def $ymm1 killed $ymm1 def $zmm1
-; AVX512-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to16}, %zmm1, %k1
-; AVX512-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512-NEXT:    vmovdqa32 %zmm2, %zmm1 {%k1}
-; AVX512-NEXT:    vpermd %ymm0, %ymm1, %ymm0
-; AVX512-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512-NEXT:    vmovaps %zmm1, %zmm0 {%k1}
+; AVX512-NEXT:    vpbroadcastd {{.*#+}} ymm2 = [7,7,7,7,7,7,7,7]
+; AVX512-NEXT:    vpcmpnleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512-NEXT:    vpblendmd %zmm3, %zmm1, %zmm3 {%k1}
+; AVX512-NEXT:    vpermd %ymm0, %ymm3, %ymm0
+; AVX512-NEXT:    vpcmpleud %zmm2, %zmm1, %k1
+; AVX512-NEXT:    vmovaps %zmm0, %zmm0 {%k1} {z}
 ; AVX512-NEXT:    # kill: def $ymm0 killed $ymm0 killed $zmm0
 ; AVX512-NEXT:    retq
 ;
 ; AVX512VL-LABEL: var_shuffle_zero_v8f32:
 ; AVX512VL:       # %bb.0:
-; AVX512VL-NEXT:    vpcmpnleud {{\.?LCPI[0-9]+_[0-9]+}}(%rip){1to8}, %ymm1, %k1
-; AVX512VL-NEXT:    vpcmpeqd %ymm2, %ymm2, %ymm2
-; AVX512VL-NEXT:    vmovdqa32 %ymm2, %ymm1 {%k1}
-; AVX512VL-NEXT:    vpermd %ymm0, %ymm1, %ymm0
-; AVX512VL-NEXT:    vpxor %xmm1, %xmm1, %xmm1
-; AVX512VL-NEXT:    vmovaps %ymm1, %ymm0 {%k1}
+; AVX512VL-NEXT:    vpbroadcastd {{.*#+}} ymm2 = [7,7,7,7,7,7,7,7]
+; AVX512VL-NEXT:    vpcmpnleud %ymm2, %ymm1, %k1
+; AVX512VL-NEXT:    vpcmpeqd %ymm3, %ymm3, %ymm3
+; AVX512VL-NEXT:    vpcmpleud %ymm2, %ymm1, %k2
+; AVX512VL-NEXT:    vmovdqa32 %ymm3, %ymm1 {%k1}
+; AVX512VL-NEXT:    vpermps %ymm0, %ymm1, %ymm0 {%k2} {z}
 ; AVX512VL-NEXT:    retq
   %cmp = icmp ugt <8 x i32> %indices, <i32 7, i32 7, i32 7, i32 7, i32 7, i32 7, i32 7, i32 7>
   %or = select <8 x i1> %cmp, <8 x i32> <i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1, i32 -1>, <8 x i32> %indices

>From b8aa447235fd88130474211142287ba07aaf938c Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Thu, 26 Jun 2025 08:25:32 +0100
Subject: [PATCH 2/2] add comment to fold

---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index da1f48ede5402..c3ef78c404267 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -48126,6 +48126,7 @@ static SDValue combineSelect(SDNode *N, SelectionDAG &DAG,
     return V;
 
   // select(~Cond, X, Y) -> select(Cond, Y, X)
+  // Limit vXi1 cases to AVX512 canonicalization of zero mask to the RHS.
   if (CondVT.getScalarType() != MVT::i1 ||
       (ISD::isBuildVectorAllZeros(LHS.getNode()) &&
        !ISD::isBuildVectorAllZeros(RHS.getNode())))



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