[llvm] [LV] Add extra check for signed oveflow for SDiv/SRem (PR #170818)

Shih-Po Hung via llvm-commits llvm-commits at lists.llvm.org
Wed Dec 10 22:46:07 PST 2025


https://github.com/arcbbb updated https://github.com/llvm/llvm-project/pull/170818

>From 5f81156dcdd2ab5414e509afa57e15a567b3aaae Mon Sep 17 00:00:00 2001
From: ShihPo Hung <shihpo.hung at sifive.com>
Date: Fri, 5 Dec 2025 00:53:15 -0800
Subject: [PATCH 1/6] [LV] Add extra check for signed oveflow for SDiv/SRem

---
 .../Transforms/Vectorize/LoopVectorize.cpp    |  14 +-
 .../Transforms/LoopVectorize/RISCV/divrem.ll  |   6 +-
 .../LoopVectorize/RISCV/tail-folding-div.ll   | 387 +++++++++++++++++-
 ...-order-recurrence-sink-replicate-region.ll |  58 ++-
 .../predicatedinst-loop-invariant.ll          |   3 +-
 5 files changed, 434 insertions(+), 34 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index f78acf31a0de2..1625deb38f0d5 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2878,11 +2878,21 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
              TheLoop->isLoopInvariant(cast<StoreInst>(I)->getValueOperand()));
   }
   case Instruction::UDiv:
-  case Instruction::SDiv:
-  case Instruction::SRem:
   case Instruction::URem:
     // If the divisor is loop-invariant no predication is needed.
     return !Legal->isInvariant(I->getOperand(1));
+  case Instruction::SDiv:
+  case Instruction::SRem: {
+    auto *LHS = I->getOperand(0);
+    auto *RHS = I->getOperand(1);
+    // If RHS is loop-invariant, signed-division overflow is possible
+    // when RHS == −1 or when it isn’t a known constant.
+    return !Legal->isInvariant(RHS) ||
+           (!Legal->isInvariant(LHS) &&
+            (!isa<ConstantInt>(RHS) ||
+             (isa<ConstantInt>(RHS) &&
+              cast<ConstantInt>(RHS)->getValue().isAllOnes())));
+  }
   }
 }
 
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/divrem.ll b/llvm/test/Transforms/LoopVectorize/RISCV/divrem.ll
index e4ba6fe9d757d..a14ffc782b6ff 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/divrem.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/divrem.ll
@@ -85,7 +85,8 @@ define void @vector_sdiv(ptr noalias nocapture %a, i64 %v, i64 %n) {
 ; CHECK-NEXT:    [[TMP10:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
 ; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[A:%.*]], i64 [[INDEX]]
 ; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.vp.load.nxv2i64.p0(ptr align 8 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP10]])
-; CHECK-NEXT:    [[TMP9:%.*]] = sdiv <vscale x 2 x i64> [[WIDE_LOAD]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP2:%.*]] = call <vscale x 2 x i64> @llvm.vp.merge.nxv2i64(<vscale x 2 x i1> splat (i1 true), <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> splat (i64 1), i32 [[TMP10]])
+; CHECK-NEXT:    [[TMP9:%.*]] = sdiv <vscale x 2 x i64> [[WIDE_LOAD]], [[TMP2]]
 ; CHECK-NEXT:    call void @llvm.vp.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP9]], ptr align 8 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP10]])
 ; CHECK-NEXT:    [[TMP8:%.*]] = zext i32 [[TMP10]] to i64
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[TMP8]], [[INDEX]]
@@ -213,7 +214,8 @@ define void @vector_srem(ptr noalias nocapture %a, i64 %v, i64 %n) {
 ; CHECK-NEXT:    [[TMP10:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
 ; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[A:%.*]], i64 [[INDEX]]
 ; CHECK-NEXT:    [[WIDE_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.vp.load.nxv2i64.p0(ptr align 8 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP10]])
-; CHECK-NEXT:    [[TMP9:%.*]] = srem <vscale x 2 x i64> [[WIDE_LOAD]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP2:%.*]] = call <vscale x 2 x i64> @llvm.vp.merge.nxv2i64(<vscale x 2 x i1> splat (i1 true), <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> splat (i64 1), i32 [[TMP10]])
+; CHECK-NEXT:    [[TMP9:%.*]] = srem <vscale x 2 x i64> [[WIDE_LOAD]], [[TMP2]]
 ; CHECK-NEXT:    call void @llvm.vp.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP9]], ptr align 8 [[TMP7]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP10]])
 ; CHECK-NEXT:    [[TMP8:%.*]] = zext i32 [[TMP10]] to i64
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[TMP8]], [[INDEX]]
diff --git a/llvm/test/Transforms/LoopVectorize/RISCV/tail-folding-div.ll b/llvm/test/Transforms/LoopVectorize/RISCV/tail-folding-div.ll
index 8cd540c3888db..dfc4e46679511 100644
--- a/llvm/test/Transforms/LoopVectorize/RISCV/tail-folding-div.ll
+++ b/llvm/test/Transforms/LoopVectorize/RISCV/tail-folding-div.ll
@@ -102,6 +102,363 @@ exit:
   ret void
 }
 
+define void @test_sdiv_divisor_invariant_nonconst(ptr noalias %a, i64 %b, ptr noalias %c) {
+; IF-EVL-LABEL: define void @test_sdiv_divisor_invariant_nonconst(
+; IF-EVL-SAME: ptr noalias [[A:%.*]], i64 [[B:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; IF-EVL-NEXT:  [[LOOP_PREHEADER:.*:]]
+; IF-EVL-NEXT:    br label %[[VECTOR_PH:.*]]
+; IF-EVL:       [[VECTOR_PH]]:
+; IF-EVL-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[B]], i64 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; IF-EVL-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IF-EVL:       [[VECTOR_BODY]]:
+; IF-EVL-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_EVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[AVL:%.*]] = phi i64 [ 1024, %[[VECTOR_PH]] ], [ [[AVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[TMP0:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
+; IF-EVL-NEXT:    [[TMP1:%.*]] = getelementptr i64, ptr [[A]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[VP_OP_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.vp.load.nxv2i64.p0(ptr align 8 [[TMP1]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP2:%.*]] = call <vscale x 2 x i64> @llvm.vp.merge.nxv2i64(<vscale x 2 x i1> splat (i1 true), <vscale x 2 x i64> [[BROADCAST_SPLAT]], <vscale x 2 x i64> splat (i64 1), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP3:%.*]] = sdiv <vscale x 2 x i64> [[VP_OP_LOAD]], [[TMP2]]
+; IF-EVL-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[C]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    call void @llvm.vp.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP3]], ptr align 8 [[TMP4]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP5:%.*]] = zext i32 [[TMP0]] to i64
+; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP5]], [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP5]]
+; IF-EVL-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
+; IF-EVL-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; IF-EVL:       [[MIDDLE_BLOCK]]:
+; IF-EVL-NEXT:    br label %[[EXIT:.*]]
+; IF-EVL:       [[EXIT]]:
+; IF-EVL-NEXT:    ret void
+;
+; NO-VP-LABEL: define void @test_sdiv_divisor_invariant_nonconst(
+; NO-VP-SAME: ptr noalias [[A:%.*]], i64 [[B:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; NO-VP-NEXT:  [[LOOP_PREHEADER:.*]]:
+; NO-VP-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP1:%.*]] = shl nuw i64 [[TMP0]], 1
+; NO-VP-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
+; NO-VP-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; NO-VP:       [[VECTOR_PH]]:
+; NO-VP-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 2
+; NO-VP-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; NO-VP-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; NO-VP-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[B]], i64 0
+; NO-VP-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; NO-VP-NEXT:    br label %[[VECTOR_BODY:.*]]
+; NO-VP:       [[VECTOR_BODY]]:
+; NO-VP-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; NO-VP-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[INDEX]]
+; NO-VP-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 2 x i64>, ptr [[TMP4]], align 8
+; NO-VP-NEXT:    [[TMP5:%.*]] = sdiv <vscale x 2 x i64> [[WIDE_LOAD]], [[BROADCAST_SPLAT]]
+; NO-VP-NEXT:    [[TMP6:%.*]] = getelementptr i64, ptr [[C]], i64 [[INDEX]]
+; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP5]], ptr [[TMP6]], align 8
+; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
+; NO-VP-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; NO-VP:       [[MIDDLE_BLOCK]]:
+; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; NO-VP:       [[SCALAR_PH]]:
+; NO-VP-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[LOOP_PREHEADER]] ]
+; NO-VP-NEXT:    br label %[[LOOP:.*]]
+; NO-VP:       [[LOOP]]:
+; NO-VP-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; NO-VP-NEXT:    [[A_GEP:%.*]] = getelementptr i64, ptr [[A]], i64 [[IV]]
+; NO-VP-NEXT:    [[TMP8:%.*]] = load i64, ptr [[A_GEP]], align 8
+; NO-VP-NEXT:    [[TMP9:%.*]] = sdiv i64 [[TMP8]], [[B]]
+; NO-VP-NEXT:    [[C_GEP:%.*]] = getelementptr i64, ptr [[C]], i64 [[IV]]
+; NO-VP-NEXT:    store i64 [[TMP9]], ptr [[C_GEP]], align 8
+; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
+; NO-VP:       [[EXIT]]:
+; NO-VP-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, %b
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1024
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+define void @test_sdiv_both_invariant_nonconst(ptr noalias %a, i64 %b, i64 %b2, ptr noalias %c) {
+; IF-EVL-LABEL: define void @test_sdiv_both_invariant_nonconst(
+; IF-EVL-SAME: ptr noalias [[A:%.*]], i64 [[B:%.*]], i64 [[B2:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; IF-EVL-NEXT:  [[LOOP_PREHEADER:.*:]]
+; IF-EVL-NEXT:    br label %[[VECTOR_PH:.*]]
+; IF-EVL:       [[VECTOR_PH]]:
+; IF-EVL-NEXT:    [[TMP0:%.*]] = sdiv i64 [[B]], [[B2]]
+; IF-EVL-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP0]], i64 0
+; IF-EVL-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; IF-EVL-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IF-EVL:       [[VECTOR_BODY]]:
+; IF-EVL-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_EVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[AVL:%.*]] = phi i64 [ 1024, %[[VECTOR_PH]] ], [ [[AVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[TMP1:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
+; IF-EVL-NEXT:    [[TMP2:%.*]] = getelementptr i64, ptr [[A]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[VP_OP_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.vp.load.nxv2i64.p0(ptr align 8 [[TMP2]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP1]])
+; IF-EVL-NEXT:    [[TMP3:%.*]] = add <vscale x 2 x i64> [[VP_OP_LOAD]], [[BROADCAST_SPLAT]]
+; IF-EVL-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[C]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    call void @llvm.vp.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP3]], ptr align 8 [[TMP4]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP1]])
+; IF-EVL-NEXT:    [[TMP5:%.*]] = zext i32 [[TMP1]] to i64
+; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP5]], [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP5]]
+; IF-EVL-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
+; IF-EVL-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; IF-EVL:       [[MIDDLE_BLOCK]]:
+; IF-EVL-NEXT:    br label %[[EXIT:.*]]
+; IF-EVL:       [[EXIT]]:
+; IF-EVL-NEXT:    ret void
+;
+; NO-VP-LABEL: define void @test_sdiv_both_invariant_nonconst(
+; NO-VP-SAME: ptr noalias [[A:%.*]], i64 [[B:%.*]], i64 [[B2:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; NO-VP-NEXT:  [[LOOP_PREHEADER:.*]]:
+; NO-VP-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP1:%.*]] = shl nuw i64 [[TMP0]], 1
+; NO-VP-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
+; NO-VP-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; NO-VP:       [[VECTOR_PH]]:
+; NO-VP-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 2
+; NO-VP-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; NO-VP-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; NO-VP-NEXT:    [[TMP4:%.*]] = sdiv i64 [[B]], [[B2]]
+; NO-VP-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 2 x i64> poison, i64 [[TMP4]], i64 0
+; NO-VP-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 2 x i64> [[BROADCAST_SPLATINSERT]], <vscale x 2 x i64> poison, <vscale x 2 x i32> zeroinitializer
+; NO-VP-NEXT:    br label %[[VECTOR_BODY:.*]]
+; NO-VP:       [[VECTOR_BODY]]:
+; NO-VP-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; NO-VP-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr [[A]], i64 [[INDEX]]
+; NO-VP-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 2 x i64>, ptr [[TMP5]], align 8
+; NO-VP-NEXT:    [[TMP6:%.*]] = add <vscale x 2 x i64> [[WIDE_LOAD]], [[BROADCAST_SPLAT]]
+; NO-VP-NEXT:    [[TMP7:%.*]] = getelementptr i64, ptr [[C]], i64 [[INDEX]]
+; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP6]], ptr [[TMP7]], align 8
+; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
+; NO-VP-NEXT:    [[TMP8:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[TMP8]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; NO-VP:       [[MIDDLE_BLOCK]]:
+; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; NO-VP:       [[SCALAR_PH]]:
+; NO-VP-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[LOOP_PREHEADER]] ]
+; NO-VP-NEXT:    br label %[[LOOP:.*]]
+; NO-VP:       [[LOOP]]:
+; NO-VP-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; NO-VP-NEXT:    [[A_GEP:%.*]] = getelementptr i64, ptr [[A]], i64 [[IV]]
+; NO-VP-NEXT:    [[TMP9:%.*]] = load i64, ptr [[A_GEP]], align 8
+; NO-VP-NEXT:    [[TMP10:%.*]] = sdiv i64 [[B]], [[B2]]
+; NO-VP-NEXT:    [[TMP11:%.*]] = add i64 [[TMP9]], [[TMP10]]
+; NO-VP-NEXT:    [[C_GEP:%.*]] = getelementptr i64, ptr [[C]], i64 [[IV]]
+; NO-VP-NEXT:    store i64 [[TMP11]], ptr [[C_GEP]], align 8
+; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; NO-VP:       [[EXIT]]:
+; NO-VP-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %b, %b2
+  %3 = add i64 %0, %2
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %3, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1024
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+define void @test_sdiv_divisor_invariant_minusone(ptr noalias %a, ptr noalias %c) {
+; IF-EVL-LABEL: define void @test_sdiv_divisor_invariant_minusone(
+; IF-EVL-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; IF-EVL-NEXT:  [[LOOP_PREHEADER:.*:]]
+; IF-EVL-NEXT:    br label %[[VECTOR_PH:.*]]
+; IF-EVL:       [[VECTOR_PH]]:
+; IF-EVL-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IF-EVL:       [[VECTOR_BODY]]:
+; IF-EVL-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_EVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[AVL:%.*]] = phi i64 [ 1024, %[[VECTOR_PH]] ], [ [[AVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[TMP0:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
+; IF-EVL-NEXT:    [[TMP1:%.*]] = getelementptr i64, ptr [[A]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[VP_OP_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.vp.load.nxv2i64.p0(ptr align 8 [[TMP1]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP2:%.*]] = call <vscale x 2 x i64> @llvm.vp.merge.nxv2i64(<vscale x 2 x i1> splat (i1 true), <vscale x 2 x i64> splat (i64 -1), <vscale x 2 x i64> splat (i64 1), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP3:%.*]] = sdiv <vscale x 2 x i64> [[VP_OP_LOAD]], [[TMP2]]
+; IF-EVL-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[C]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    call void @llvm.vp.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP3]], ptr align 8 [[TMP4]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP5:%.*]] = zext i32 [[TMP0]] to i64
+; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP5]], [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP5]]
+; IF-EVL-NEXT:    [[TMP6:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
+; IF-EVL-NEXT:    br i1 [[TMP6]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; IF-EVL:       [[MIDDLE_BLOCK]]:
+; IF-EVL-NEXT:    br label %[[EXIT:.*]]
+; IF-EVL:       [[EXIT]]:
+; IF-EVL-NEXT:    ret void
+;
+; NO-VP-LABEL: define void @test_sdiv_divisor_invariant_minusone(
+; NO-VP-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; NO-VP-NEXT:  [[LOOP_PREHEADER:.*]]:
+; NO-VP-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP1:%.*]] = shl nuw i64 [[TMP0]], 1
+; NO-VP-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
+; NO-VP-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; NO-VP:       [[VECTOR_PH]]:
+; NO-VP-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 2
+; NO-VP-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; NO-VP-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; NO-VP-NEXT:    br label %[[VECTOR_BODY:.*]]
+; NO-VP:       [[VECTOR_BODY]]:
+; NO-VP-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; NO-VP-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[INDEX]]
+; NO-VP-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 2 x i64>, ptr [[TMP4]], align 8
+; NO-VP-NEXT:    [[TMP5:%.*]] = sdiv <vscale x 2 x i64> [[WIDE_LOAD]], splat (i64 -1)
+; NO-VP-NEXT:    [[TMP6:%.*]] = getelementptr i64, ptr [[C]], i64 [[INDEX]]
+; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP5]], ptr [[TMP6]], align 8
+; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
+; NO-VP-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; NO-VP:       [[MIDDLE_BLOCK]]:
+; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; NO-VP:       [[SCALAR_PH]]:
+; NO-VP-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[LOOP_PREHEADER]] ]
+; NO-VP-NEXT:    br label %[[LOOP:.*]]
+; NO-VP:       [[LOOP]]:
+; NO-VP-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; NO-VP-NEXT:    [[A_GEP:%.*]] = getelementptr i64, ptr [[A]], i64 [[IV]]
+; NO-VP-NEXT:    [[TMP8:%.*]] = load i64, ptr [[A_GEP]], align 8
+; NO-VP-NEXT:    [[TMP9:%.*]] = sdiv i64 [[TMP8]], -1
+; NO-VP-NEXT:    [[C_GEP:%.*]] = getelementptr i64, ptr [[C]], i64 [[IV]]
+; NO-VP-NEXT:    store i64 [[TMP9]], ptr [[C_GEP]], align 8
+; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP9:![0-9]+]]
+; NO-VP:       [[EXIT]]:
+; NO-VP-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, -1
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1024
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+define void @test_sdiv_divisor_invariant_safeimm(ptr noalias %a, ptr noalias %c) {
+; IF-EVL-LABEL: define void @test_sdiv_divisor_invariant_safeimm(
+; IF-EVL-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; IF-EVL-NEXT:  [[LOOP_PREHEADER:.*:]]
+; IF-EVL-NEXT:    br label %[[VECTOR_PH:.*]]
+; IF-EVL:       [[VECTOR_PH]]:
+; IF-EVL-NEXT:    br label %[[VECTOR_BODY:.*]]
+; IF-EVL:       [[VECTOR_BODY]]:
+; IF-EVL-NEXT:    [[EVL_BASED_IV:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_EVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[AVL:%.*]] = phi i64 [ 1024, %[[VECTOR_PH]] ], [ [[AVL_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; IF-EVL-NEXT:    [[TMP0:%.*]] = call i32 @llvm.experimental.get.vector.length.i64(i64 [[AVL]], i32 2, i1 true)
+; IF-EVL-NEXT:    [[TMP1:%.*]] = getelementptr i64, ptr [[A]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[VP_OP_LOAD:%.*]] = call <vscale x 2 x i64> @llvm.vp.load.nxv2i64.p0(ptr align 8 [[TMP1]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP2:%.*]] = sdiv <vscale x 2 x i64> [[VP_OP_LOAD]], splat (i64 3)
+; IF-EVL-NEXT:    [[TMP3:%.*]] = getelementptr i64, ptr [[C]], i64 [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    call void @llvm.vp.store.nxv2i64.p0(<vscale x 2 x i64> [[TMP2]], ptr align 8 [[TMP3]], <vscale x 2 x i1> splat (i1 true), i32 [[TMP0]])
+; IF-EVL-NEXT:    [[TMP4:%.*]] = zext i32 [[TMP0]] to i64
+; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP4]], [[EVL_BASED_IV]]
+; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP4]]
+; IF-EVL-NEXT:    [[TMP5:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
+; IF-EVL-NEXT:    br i1 [[TMP5]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; IF-EVL:       [[MIDDLE_BLOCK]]:
+; IF-EVL-NEXT:    br label %[[EXIT:.*]]
+; IF-EVL:       [[EXIT]]:
+; IF-EVL-NEXT:    ret void
+;
+; NO-VP-LABEL: define void @test_sdiv_divisor_invariant_safeimm(
+; NO-VP-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) #[[ATTR0]] {
+; NO-VP-NEXT:  [[LOOP_PREHEADER:.*]]:
+; NO-VP-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP1:%.*]] = shl nuw i64 [[TMP0]], 1
+; NO-VP-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
+; NO-VP-NEXT:    br i1 [[MIN_ITERS_CHECK]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; NO-VP:       [[VECTOR_PH]]:
+; NO-VP-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; NO-VP-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 2
+; NO-VP-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; NO-VP-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; NO-VP-NEXT:    br label %[[VECTOR_BODY:.*]]
+; NO-VP:       [[VECTOR_BODY]]:
+; NO-VP-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[VECTOR_BODY]] ]
+; NO-VP-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[INDEX]]
+; NO-VP-NEXT:    [[WIDE_LOAD:%.*]] = load <vscale x 2 x i64>, ptr [[TMP4]], align 8
+; NO-VP-NEXT:    [[TMP5:%.*]] = sdiv <vscale x 2 x i64> [[WIDE_LOAD]], splat (i64 3)
+; NO-VP-NEXT:    [[TMP6:%.*]] = getelementptr i64, ptr [[C]], i64 [[INDEX]]
+; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP5]], ptr [[TMP6]], align 8
+; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
+; NO-VP-NEXT:    [[TMP7:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[TMP7]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
+; NO-VP:       [[MIDDLE_BLOCK]]:
+; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
+; NO-VP:       [[SCALAR_PH]]:
+; NO-VP-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], %[[MIDDLE_BLOCK]] ], [ 0, %[[LOOP_PREHEADER]] ]
+; NO-VP-NEXT:    br label %[[LOOP:.*]]
+; NO-VP:       [[LOOP]]:
+; NO-VP-NEXT:    [[IV:%.*]] = phi i64 [ [[IV_NEXT:%.*]], %[[LOOP]] ], [ [[BC_RESUME_VAL]], %[[SCALAR_PH]] ]
+; NO-VP-NEXT:    [[A_GEP:%.*]] = getelementptr i64, ptr [[A]], i64 [[IV]]
+; NO-VP-NEXT:    [[TMP8:%.*]] = load i64, ptr [[A_GEP]], align 8
+; NO-VP-NEXT:    [[TMP9:%.*]] = sdiv i64 [[TMP8]], 3
+; NO-VP-NEXT:    [[C_GEP:%.*]] = getelementptr i64, ptr [[C]], i64 [[IV]]
+; NO-VP-NEXT:    store i64 [[TMP9]], ptr [[C_GEP]], align 8
+; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
+; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP11:![0-9]+]]
+; NO-VP:       [[EXIT]]:
+; NO-VP-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, 3
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1024
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
 
 define void @test_udiv(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; IF-EVL-LABEL: define void @test_udiv(
@@ -126,7 +483,7 @@ define void @test_udiv(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP14]], [[EVL_BASED_IV]]
 ; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP14]]
 ; IF-EVL-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
-; IF-EVL-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; IF-EVL-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
 ; IF-EVL:       [[MIDDLE_BLOCK]]:
 ; IF-EVL-NEXT:    br label %[[EXIT:.*]]
 ; IF-EVL:       [[EXIT]]:
@@ -156,7 +513,7 @@ define void @test_udiv(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP8]], ptr [[TMP9]], align 8
 ; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
 ; NO-VP-NEXT:    [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; NO-VP-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; NO-VP-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP12:![0-9]+]]
 ; NO-VP:       [[MIDDLE_BLOCK]]:
 ; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
 ; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
@@ -174,7 +531,7 @@ define void @test_udiv(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; NO-VP-NEXT:    store i64 [[TMP2]], ptr [[C_GEP]], align 8
 ; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
 ; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
-; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP13:![0-9]+]]
 ; NO-VP:       [[EXIT]]:
 ; NO-VP-NEXT:    ret void
 ;
@@ -221,7 +578,7 @@ define void @test_srem(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP14]], [[EVL_BASED_IV]]
 ; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP14]]
 ; IF-EVL-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
-; IF-EVL-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; IF-EVL-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
 ; IF-EVL:       [[MIDDLE_BLOCK]]:
 ; IF-EVL-NEXT:    br label %[[EXIT:.*]]
 ; IF-EVL:       [[EXIT]]:
@@ -251,7 +608,7 @@ define void @test_srem(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP8]], ptr [[TMP9]], align 8
 ; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
 ; NO-VP-NEXT:    [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; NO-VP-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; NO-VP-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
 ; NO-VP:       [[MIDDLE_BLOCK]]:
 ; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
 ; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
@@ -269,7 +626,7 @@ define void @test_srem(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; NO-VP-NEXT:    store i64 [[TMP2]], ptr [[C_GEP]], align 8
 ; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
 ; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
-; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP7:![0-9]+]]
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP15:![0-9]+]]
 ; NO-VP:       [[EXIT]]:
 ; NO-VP-NEXT:    ret void
 ;
@@ -316,7 +673,7 @@ define void @test_urem(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; IF-EVL-NEXT:    [[INDEX_EVL_NEXT]] = add nuw i64 [[TMP14]], [[EVL_BASED_IV]]
 ; IF-EVL-NEXT:    [[AVL_NEXT]] = sub nuw i64 [[AVL]], [[TMP14]]
 ; IF-EVL-NEXT:    [[TMP13:%.*]] = icmp eq i64 [[AVL_NEXT]], 0
-; IF-EVL-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; IF-EVL-NEXT:    br i1 [[TMP13]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
 ; IF-EVL:       [[MIDDLE_BLOCK]]:
 ; IF-EVL-NEXT:    br label %[[EXIT:.*]]
 ; IF-EVL:       [[EXIT]]:
@@ -346,7 +703,7 @@ define void @test_urem(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; NO-VP-NEXT:    store <vscale x 2 x i64> [[TMP8]], ptr [[TMP9]], align 8
 ; NO-VP-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
 ; NO-VP-NEXT:    [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; NO-VP-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; NO-VP-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP16:![0-9]+]]
 ; NO-VP:       [[MIDDLE_BLOCK]]:
 ; NO-VP-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
 ; NO-VP-NEXT:    br i1 [[CMP_N]], label %[[EXIT:.*]], label %[[SCALAR_PH]]
@@ -364,7 +721,7 @@ define void @test_urem(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
 ; NO-VP-NEXT:    store i64 [[TMP2]], ptr [[C_GEP]], align 8
 ; NO-VP-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
 ; NO-VP-NEXT:    [[DONE:%.*]] = icmp eq i64 [[IV_NEXT]], 1024
-; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP9:![0-9]+]]
+; NO-VP-NEXT:    br i1 [[DONE]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP17:![0-9]+]]
 ; NO-VP:       [[EXIT]]:
 ; NO-VP-NEXT:    ret void
 ;
@@ -394,6 +751,10 @@ exit:
 ; IF-EVL: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]], [[META2]]}
 ; IF-EVL: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
 ; IF-EVL: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]]}
+; IF-EVL: [[LOOP6]] = distinct !{[[LOOP6]], [[META1]], [[META2]]}
+; IF-EVL: [[LOOP7]] = distinct !{[[LOOP7]], [[META1]], [[META2]]}
+; IF-EVL: [[LOOP8]] = distinct !{[[LOOP8]], [[META1]], [[META2]]}
+; IF-EVL: [[LOOP9]] = distinct !{[[LOOP9]], [[META1]], [[META2]]}
 ;.
 ; NO-VP: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
 ; NO-VP: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
@@ -405,4 +766,12 @@ exit:
 ; NO-VP: [[LOOP7]] = distinct !{[[LOOP7]], [[META2]], [[META1]]}
 ; NO-VP: [[LOOP8]] = distinct !{[[LOOP8]], [[META1]], [[META2]]}
 ; NO-VP: [[LOOP9]] = distinct !{[[LOOP9]], [[META2]], [[META1]]}
+; NO-VP: [[LOOP10]] = distinct !{[[LOOP10]], [[META1]], [[META2]]}
+; NO-VP: [[LOOP11]] = distinct !{[[LOOP11]], [[META2]], [[META1]]}
+; NO-VP: [[LOOP12]] = distinct !{[[LOOP12]], [[META1]], [[META2]]}
+; NO-VP: [[LOOP13]] = distinct !{[[LOOP13]], [[META2]], [[META1]]}
+; NO-VP: [[LOOP14]] = distinct !{[[LOOP14]], [[META1]], [[META2]]}
+; NO-VP: [[LOOP15]] = distinct !{[[LOOP15]], [[META2]], [[META1]]}
+; NO-VP: [[LOOP16]] = distinct !{[[LOOP16]], [[META1]], [[META2]]}
+; NO-VP: [[LOOP17]] = distinct !{[[LOOP17]], [[META2]], [[META1]]}
 ;.
diff --git a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
index b72cbd333cb79..42b34d4a00743 100644
--- a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
+++ b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
@@ -49,8 +49,6 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   WIDEN-CAST ir<%conv> = sext vp<[[PRED1]]> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%0>, ir<%conv>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
-; CHECK-NEXT:   WIDEN ir<%add> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT: Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <xVFxUF> pred.store: {
@@ -59,16 +57,18 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT:   Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.if:
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%gep.dst> = getelementptr ir<%dst>, vp<[[STEPS]]>
+; CHECK-NEXT:     REPLICATE ir<%add> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE store ir<%add>, ir<%gep.dst>
 ; CHECK-NEXT:   Successor(s): pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.1
+; CHECK-NEXT: Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.1:
+; CHECK-NEXT: loop.2:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -210,8 +210,25 @@ define i32 @sink_replicate_region_3_reduction(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:   EMIT vp<[[WIDEN_CAN:%.+]]> = WIDEN-CANONICAL-INDUCTION vp<[[CAN_IV]]>
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule vp<[[WIDEN_CAN]]>, vp<[[BTC]]>
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
-; CHECK-NEXT:   WIDEN ir<%add> = add ir<%rem>, ir<%recur.next>
+; CHECK-NEXT: Successor(s): pred.srem
+; CHECK-EMPTY:
+; CHECK-NEXT:  <xVFxUF> pred.srem: {
+; CHECK-NEXT:    pred.srem.entry:
+; CHECK-NEXT:      BRANCH-ON-MASK vp<[[MASK]]>
+; CHECK-NEXT:    Successor(s): pred.srem.if, pred.srem.continue
+; CHECK-EMPTY:
+; CHECK-NEXT:    pred.srem.if:
+; CHECK-NEXT:      REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
+; CHECK-NEXT:    Successor(s): pred.srem.continue
+; CHECK-EMPTY:
+; CHECK-NEXT:   pred.srem.continue:
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%8> = ir<%rem>
+; CHECK-NEXT:   No successors
+; CHECK-NEXT:  }
+; CHECK-NEXT: Successor(s): loop.0
+; CHECK-EMPTY:
+; CHECK-NEXT: loop.0:
+; CHECK-NEXT:   WIDEN ir<%add> = add vp<%8>, ir<%recur.next>
 ; CHECK-NEXT:   WIDEN ir<%and.red.next> = and ir<%and.red>, ir<%add>
 ; CHECK-NEXT:   EMIT vp<[[SEL:%.+]]> = select vp<[[MASK]]>, ir<%and.red.next>, ir<%and.red>
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
@@ -293,7 +310,6 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   WIDEN-CAST ir<%conv> = sext vp<[[PRED]]> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%0>, ir<%conv>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT: Successor(s): pred.load
 ; CHECK-EMPTY:
 ; CHECK:      <xVFxUF> pred.load: {
@@ -302,18 +318,20 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:   Successor(s): pred.load.if, pred.load.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.load.if:
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
 ; CHECK-NEXT:     REPLICATE ir<%lv.2> = load ir<%gep> (S->V)
 ; CHECK-NEXT:   Successor(s): pred.load.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.load.continue:
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%9> = ir<%lv.2>
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%9> = ir<%rem>
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%10> = ir<%lv.2>
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT:   Successor(s): loop.1
+; CHECK-NEXT:   Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK-NEXT:  loop.1:
-; CHECK-NEXT:    WIDEN ir<%add.1> = add ir<%conv>, ir<%rem>
-; CHECK-NEXT:    WIDEN-CAST ir<%conv.lv.2> = sext vp<%9> to i32
+; CHECK-NEXT:  loop.2:
+; CHECK-NEXT:    WIDEN ir<%add.1> = add ir<%conv>, vp<%9>
+; CHECK-NEXT:    WIDEN-CAST ir<%conv.lv.2> = sext vp<%10> to i32
 ; CHECK-NEXT:    WIDEN ir<%add> = add ir<%add.1>, ir<%conv.lv.2>
 ; CHECK-NEXT:  Successor(s): pred.store
 ; CHECK-EMPTY:
@@ -330,9 +348,9 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:    pred.store.continue:
 ; CHECK-NEXT:    No successors
 ; CHECK-NEXT:  }
-; CHECK-NEXT:  Successor(s): loop.2
+; CHECK-NEXT:  Successor(s): loop.3
 ; CHECK-EMPTY:
-; CHECK:      loop.2:
+; CHECK:      loop.3:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -394,7 +412,6 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   ir<%iv> = WIDEN-INDUCTION ir<0>, ir<1>, vp<[[VF]]>
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule ir<%iv>, vp<[[BTC]]>
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT: Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <xVFxUF> pred.store: {
@@ -404,6 +421,7 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.if:
 ; CHECK-NEXT:     vp<[[STEPS:%.+]]> = SCALAR-STEPS vp<[[CAN_IV]]>, ir<1>
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%rem.div> = sdiv ir<20>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE ir<%gep> = getelementptr ir<%ptr>, vp<[[STEPS]]>
 ; CHECK-NEXT:     REPLICATE store ir<%rem.div>, ir<%gep>
@@ -414,9 +432,9 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.2
+; CHECK-NEXT: Successor(s): loop.3
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.2:
+; CHECK-NEXT: loop.3:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -474,7 +492,6 @@ define void @need_new_block_after_sinking_pr56146(i32 %x, ptr %src, ptr noalias
 ; CHECK-NEXT:     EMIT vp<[[CMP:%.+]]> = icmp ule vp<[[WIDE_IV]]>, vp<[[BTC]]>
 ; CHECK-NEXT:     CLONE ir<[[L]]> = load ir<%src>
 ; CHECK-NEXT:     EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%.pn>, ir<[[L]]>
-; CHECK-NEXT:     WIDEN ir<%val> = sdiv vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:  Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   <xVFxUF> pred.store: {
@@ -483,6 +500,7 @@ define void @need_new_block_after_sinking_pr56146(i32 %x, ptr %src, ptr noalias
 ; CHECK-NEXT:     Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:     pred.store.if:
+; CHECK-NEXT:       REPLICATE ir<%val> = sdiv vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:       vp<[[SCALAR_STEPS:%.+]]> = SCALAR-STEPS vp<[[DERIVED_IV]]>, ir<1>, vp<[[VF]]>
 ; CHECK-NEXT:       REPLICATE ir<%gep.dst> = getelementptr ir<%dst>, vp<[[SCALAR_STEPS]]>
 ; CHECK-NEXT:       REPLICATE store ir<%val>, ir<%gep.dst>
@@ -491,9 +509,9 @@ define void @need_new_block_after_sinking_pr56146(i32 %x, ptr %src, ptr noalias
 ; CHECK-NEXT:     pred.store.continue:
 ; CHECK-NEXT:     No successors
 ; CHECK-NEXT:   }
-; CHECK-NEXT:   Successor(s): loop.0
+; CHECK-NEXT:   Successor(s): loop.1
 ; CHECK-EMPTY:
-; CHECK-NEXT:   loop.0:
+; CHECK-NEXT:   loop.1:
 ; CHECK-NEXT:     EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:     EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT:   No successors
diff --git a/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll b/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll
index c94e42ddb718a..05d1fe8413a52 100644
--- a/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll
+++ b/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll
@@ -115,7 +115,8 @@ define void @loop_invariant_srem(ptr %p, i64 %a, i8 %b) {
 ; CHECK-NEXT:    [[PREDPHI:%.*]] = select <4 x i1> [[TMP5]], <4 x i32> [[TMP3]], <4 x i32> [[TMP2]]
 ; CHECK-NEXT:    [[TMP7:%.*]] = shl <4 x i32> [[PREDPHI]], splat (i32 8)
 ; CHECK-NEXT:    [[TMP8:%.*]] = trunc <4 x i32> [[TMP7]] to <4 x i8>
-; CHECK-NEXT:    [[TMP11:%.*]] = srem <4 x i8> [[VEC_IND1]], [[TMP8]]
+; CHECK-NEXT:    [[TMP9:%.*]] = select <4 x i1> [[TMP4]], <4 x i8> [[TMP8]], <4 x i8> splat (i8 1)
+; CHECK-NEXT:    [[TMP11:%.*]] = srem <4 x i8> [[VEC_IND1]], [[TMP9]]
 ; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <4 x i1> [[TMP4]], i32 0
 ; CHECK-NEXT:    br i1 [[TMP10]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
 ; CHECK:       [[PRED_STORE_IF]]:

>From b3771fd2b36a6fdce082ec2ff533e82eaa58562b Mon Sep 17 00:00:00 2001
From: ShihPo Hung <shihpo.hung at sifive.com>
Date: Fri, 5 Dec 2025 09:58:37 -0800
Subject: [PATCH 2/6] Address comments

---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 1625deb38f0d5..588cdd7049833 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2890,8 +2890,7 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
     return !Legal->isInvariant(RHS) ||
            (!Legal->isInvariant(LHS) &&
             (!isa<ConstantInt>(RHS) ||
-             (isa<ConstantInt>(RHS) &&
-              cast<ConstantInt>(RHS)->getValue().isAllOnes())));
+             (isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isMinusOne())));
   }
   }
 }

>From d80f3df7908ec500076c145bd7a74a897211ac6c Mon Sep 17 00:00:00 2001
From: ShihPo Hung <shihpo.hung at sifive.com>
Date: Sun, 7 Dec 2025 23:36:49 -0800
Subject: [PATCH 3/6] Use SCEV to detect LHS range

---
 .../Transforms/Vectorize/LoopVectorize.cpp    | 10 ++--
 ...-order-recurrence-sink-replicate-region.ll | 52 ++++++-------------
 .../predicatedinst-loop-invariant.ll          |  3 +-
 3 files changed, 24 insertions(+), 41 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 588cdd7049833..7668fe9767136 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2886,11 +2886,13 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
     auto *LHS = I->getOperand(0);
     auto *RHS = I->getOperand(1);
     // If RHS is loop-invariant, signed-division overflow is possible
-    // when RHS == −1 or when it isn’t a known constant.
+    // when LHS can be INT_MIN.
+    ScalarEvolution &SE = *PSE.getSE();
+    IntegerType *LHSTy = dyn_cast<IntegerType>(LHS->getType());
+    llvm::ConstantRange LHSRange = SE.getSignedRange(SE.getSCEV(LHS));
+    llvm::APInt Min = llvm::APInt::getSignedMinValue(LHSTy->getBitWidth());
     return !Legal->isInvariant(RHS) ||
-           (!Legal->isInvariant(LHS) &&
-            (!isa<ConstantInt>(RHS) ||
-             (isa<ConstantInt>(RHS) && cast<ConstantInt>(RHS)->isMinusOne())));
+           (!Legal->isInvariant(LHS) && LHSRange.contains(Min));
   }
   }
 }
diff --git a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
index 42b34d4a00743..23c004353339b 100644
--- a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
+++ b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
@@ -49,6 +49,8 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   WIDEN-CAST ir<%conv> = sext vp<[[PRED1]]> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%0>, ir<%conv>
+; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
+; CHECK-NEXT:   WIDEN ir<%add> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT: Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <xVFxUF> pred.store: {
@@ -57,18 +59,16 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT:   Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.if:
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%gep.dst> = getelementptr ir<%dst>, vp<[[STEPS]]>
-; CHECK-NEXT:     REPLICATE ir<%add> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE store ir<%add>, ir<%gep.dst>
 ; CHECK-NEXT:   Successor(s): pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.2
+; CHECK-NEXT: Successor(s): loop.1
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.2:
+; CHECK-NEXT: loop.1:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -210,25 +210,8 @@ define i32 @sink_replicate_region_3_reduction(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:   EMIT vp<[[WIDEN_CAN:%.+]]> = WIDEN-CANONICAL-INDUCTION vp<[[CAN_IV]]>
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule vp<[[WIDEN_CAN]]>, vp<[[BTC]]>
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT: Successor(s): pred.srem
-; CHECK-EMPTY:
-; CHECK-NEXT:  <xVFxUF> pred.srem: {
-; CHECK-NEXT:    pred.srem.entry:
-; CHECK-NEXT:      BRANCH-ON-MASK vp<[[MASK]]>
-; CHECK-NEXT:    Successor(s): pred.srem.if, pred.srem.continue
-; CHECK-EMPTY:
-; CHECK-NEXT:    pred.srem.if:
-; CHECK-NEXT:      REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
-; CHECK-NEXT:    Successor(s): pred.srem.continue
-; CHECK-EMPTY:
-; CHECK-NEXT:   pred.srem.continue:
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%8> = ir<%rem>
-; CHECK-NEXT:   No successors
-; CHECK-NEXT:  }
-; CHECK-NEXT: Successor(s): loop.0
-; CHECK-EMPTY:
-; CHECK-NEXT: loop.0:
-; CHECK-NEXT:   WIDEN ir<%add> = add vp<%8>, ir<%recur.next>
+; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
+; CHECK-NEXT:   WIDEN ir<%add> = add ir<%rem>, ir<%recur.next>
 ; CHECK-NEXT:   WIDEN ir<%and.red.next> = and ir<%and.red>, ir<%add>
 ; CHECK-NEXT:   EMIT vp<[[SEL:%.+]]> = select vp<[[MASK]]>, ir<%and.red.next>, ir<%and.red>
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
@@ -310,6 +293,7 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   WIDEN-CAST ir<%conv> = sext vp<[[PRED]]> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%0>, ir<%conv>
+; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT: Successor(s): pred.load
 ; CHECK-EMPTY:
 ; CHECK:      <xVFxUF> pred.load: {
@@ -318,20 +302,18 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:   Successor(s): pred.load.if, pred.load.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.load.if:
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
 ; CHECK-NEXT:     REPLICATE ir<%lv.2> = load ir<%gep> (S->V)
 ; CHECK-NEXT:   Successor(s): pred.load.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.load.continue:
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%9> = ir<%rem>
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%10> = ir<%lv.2>
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%9> = ir<%lv.2>
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT:   Successor(s): loop.2
+; CHECK-NEXT:   Successor(s): loop.1
 ; CHECK-EMPTY:
-; CHECK-NEXT:  loop.2:
-; CHECK-NEXT:    WIDEN ir<%add.1> = add ir<%conv>, vp<%9>
-; CHECK-NEXT:    WIDEN-CAST ir<%conv.lv.2> = sext vp<%10> to i32
+; CHECK-NEXT:  loop.1:
+; CHECK-NEXT:    WIDEN ir<%add.1> = add ir<%conv>, ir<%rem>
+; CHECK-NEXT:    WIDEN-CAST ir<%conv.lv.2> = sext vp<%9> to i32
 ; CHECK-NEXT:    WIDEN ir<%add> = add ir<%add.1>, ir<%conv.lv.2>
 ; CHECK-NEXT:  Successor(s): pred.store
 ; CHECK-EMPTY:
@@ -348,9 +330,9 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:    pred.store.continue:
 ; CHECK-NEXT:    No successors
 ; CHECK-NEXT:  }
-; CHECK-NEXT:  Successor(s): loop.3
+; CHECK-NEXT:  Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK:      loop.3:
+; CHECK:      loop.2:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -412,6 +394,7 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   ir<%iv> = WIDEN-INDUCTION ir<0>, ir<1>, vp<[[VF]]>
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule ir<%iv>, vp<[[BTC]]>
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
+; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT: Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <xVFxUF> pred.store: {
@@ -421,7 +404,6 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.if:
 ; CHECK-NEXT:     vp<[[STEPS:%.+]]> = SCALAR-STEPS vp<[[CAN_IV]]>, ir<1>
-; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%rem.div> = sdiv ir<20>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE ir<%gep> = getelementptr ir<%ptr>, vp<[[STEPS]]>
 ; CHECK-NEXT:     REPLICATE store ir<%rem.div>, ir<%gep>
@@ -432,9 +414,9 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.3
+; CHECK-NEXT: Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.3:
+; CHECK-NEXT: loop.2:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
diff --git a/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll b/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll
index 05d1fe8413a52..c94e42ddb718a 100644
--- a/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll
+++ b/llvm/test/Transforms/LoopVectorize/predicatedinst-loop-invariant.ll
@@ -115,8 +115,7 @@ define void @loop_invariant_srem(ptr %p, i64 %a, i8 %b) {
 ; CHECK-NEXT:    [[PREDPHI:%.*]] = select <4 x i1> [[TMP5]], <4 x i32> [[TMP3]], <4 x i32> [[TMP2]]
 ; CHECK-NEXT:    [[TMP7:%.*]] = shl <4 x i32> [[PREDPHI]], splat (i32 8)
 ; CHECK-NEXT:    [[TMP8:%.*]] = trunc <4 x i32> [[TMP7]] to <4 x i8>
-; CHECK-NEXT:    [[TMP9:%.*]] = select <4 x i1> [[TMP4]], <4 x i8> [[TMP8]], <4 x i8> splat (i8 1)
-; CHECK-NEXT:    [[TMP11:%.*]] = srem <4 x i8> [[VEC_IND1]], [[TMP9]]
+; CHECK-NEXT:    [[TMP11:%.*]] = srem <4 x i8> [[VEC_IND1]], [[TMP8]]
 ; CHECK-NEXT:    [[TMP10:%.*]] = extractelement <4 x i1> [[TMP4]], i32 0
 ; CHECK-NEXT:    br i1 [[TMP10]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
 ; CHECK:       [[PRED_STORE_IF]]:

>From 9b71a7f2a4a4b6ecf8f2bd8e1e758151112cd393 Mon Sep 17 00:00:00 2001
From: ShihPo Hung <shihpo.hung at sifive.com>
Date: Mon, 8 Dec 2025 00:11:17 -0800
Subject: [PATCH 4/6] Use isMinSignedValue to check

---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 7668fe9767136..353dd7a64571c 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2888,11 +2888,9 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
     // If RHS is loop-invariant, signed-division overflow is possible
     // when LHS can be INT_MIN.
     ScalarEvolution &SE = *PSE.getSE();
-    IntegerType *LHSTy = dyn_cast<IntegerType>(LHS->getType());
-    llvm::ConstantRange LHSRange = SE.getSignedRange(SE.getSCEV(LHS));
-    llvm::APInt Min = llvm::APInt::getSignedMinValue(LHSTy->getBitWidth());
     return !Legal->isInvariant(RHS) ||
-           (!Legal->isInvariant(LHS) && LHSRange.contains(Min));
+           (!Legal->isInvariant(LHS) &&
+            SE.getSignedRangeMin(SE.getSCEV(LHS)).isMinSignedValue());
   }
   }
 }

>From 0e2403a4c2e013eb99589c1d20f8969fd2246492 Mon Sep 17 00:00:00 2001
From: ShihPo Hung <shihpo.hung at sifive.com>
Date: Wed, 10 Dec 2025 01:14:39 -0800
Subject: [PATCH 5/6] Add more tests

---
 .../Transforms/Vectorize/LoopVectorize.cpp    |  30 +-
 ...-order-recurrence-sink-replicate-region.ll |  52 +-
 .../LoopVectorize/tail-folding-div.ll         | 550 ++++++++++++++++++
 3 files changed, 610 insertions(+), 22 deletions(-)
 create mode 100644 llvm/test/Transforms/LoopVectorize/tail-folding-div.ll

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 353dd7a64571c..ab3adb9dda9ba 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2885,12 +2885,32 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
   case Instruction::SRem: {
     auto *LHS = I->getOperand(0);
     auto *RHS = I->getOperand(1);
-    // If RHS is loop-invariant, signed-division overflow is possible
-    // when LHS can be INT_MIN.
     ScalarEvolution &SE = *PSE.getSE();
-    return !Legal->isInvariant(RHS) ||
-           (!Legal->isInvariant(LHS) &&
-            SE.getSignedRangeMin(SE.getSCEV(LHS)).isMinSignedValue());
+    auto *LHSSC = SE.getSCEV(LHS);
+    auto *RHSSC = SE.getSCEV(RHS);
+    unsigned Bits = SE.getTypeSizeInBits(LHSSC->getType());
+    APInt MinusOne = APInt::getAllOnes(Bits);
+    bool MayBeNegOne = SE.getSignedRange(RHSSC).contains(MinusOne);
+
+    // No predicate if RHS have no masked-off lanes and not -1.
+    if (isa<SCEVAddRecExpr>(RHSSC) && !MayBeNegOne)
+      return false;
+
+    // Prediate if RHS may have masked-off lanes.
+    if (!Legal->isInvariant(RHS))
+      return true;
+
+    // No predicate if LHS have no masked-off lanes and not INT_MIN.
+    if (isa<SCEVAddRecExpr>(LHSSC) &&
+        !SE.getSignedRangeMin(SE.getSCEV(LHS)).isMinSignedValue())
+      return false;
+
+    // No predicate if both are loop invariant and can be hoisted.
+    if (Legal->isInvariant(LHS))
+      return false;
+
+    // Predicate if RHS contain -1.
+    return MayBeNegOne;
   }
   }
 }
diff --git a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
index 23c004353339b..3d7d7ed854d2b 100644
--- a/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
+++ b/llvm/test/Transforms/LoopVectorize/first-order-recurrence-sink-replicate-region.ll
@@ -49,8 +49,6 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   WIDEN-CAST ir<%conv> = sext vp<[[PRED1]]> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%0>, ir<%conv>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
-; CHECK-NEXT:   WIDEN ir<%add> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT: Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <xVFxUF> pred.store: {
@@ -59,16 +57,18 @@ define void @sink_replicate_region_1(i32 %x, ptr %ptr, ptr noalias %dst) optsize
 ; CHECK-NEXT:   Successor(s): pred.store.if, pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.if:
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%gep.dst> = getelementptr ir<%dst>, vp<[[STEPS]]>
+; CHECK-NEXT:     REPLICATE ir<%add> = add ir<%conv>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE store ir<%add>, ir<%gep.dst>
 ; CHECK-NEXT:   Successor(s): pred.store.continue
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.1
+; CHECK-NEXT: Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.1:
+; CHECK-NEXT: loop.2:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -210,8 +210,25 @@ define i32 @sink_replicate_region_3_reduction(i32 %x, i8 %y, ptr %ptr) optsize {
 ; CHECK-NEXT:   EMIT vp<[[WIDEN_CAN:%.+]]> = WIDEN-CANONICAL-INDUCTION vp<[[CAN_IV]]>
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule vp<[[WIDEN_CAN]]>, vp<[[BTC]]>
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
-; CHECK-NEXT:   WIDEN ir<%add> = add ir<%rem>, ir<%recur.next>
+; CHECK-NEXT: Successor(s): pred.srem
+; CHECK-EMPTY:
+; CHECK-NEXT: <xVFxUF> pred.srem: {
+; CHECK-NEXT:   pred.srem.entry:
+; CHECK-NEXT:     BRANCH-ON-MASK vp<[[MASK]]>
+; CHECK-NEXT:   Successor(s): pred.srem.if, pred.srem.continue
+; CHECK-EMPTY:
+; CHECK-NEXT:   pred.srem.if:
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x> (S->V)
+; CHECK-NEXT:   Successor(s): pred.srem.continue
+; CHECK-EMPTY:
+; CHECK-NEXT:   pred.srem.continue:
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<[[REM:%.+]]> = ir<%rem>
+; CHECK-NEXT:   No successors
+; CHECK-NEXT: }
+; CHECK-NEXT: Successor(s): loop.0
+; CHECK-EMPTY:
+; CHECK-NEXT: loop.0:
+; CHECK-NEXT:   WIDEN ir<%add> = add vp<[[REM]]>, ir<%recur.next>
 ; CHECK-NEXT:   WIDEN ir<%and.red.next> = and ir<%and.red>, ir<%add>
 ; CHECK-NEXT:   EMIT vp<[[SEL:%.+]]> = select vp<[[MASK]]>, ir<%and.red.next>, ir<%and.red>
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
@@ -293,7 +310,6 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT: loop.0:
 ; CHECK-NEXT:   WIDEN-CAST ir<%conv> = sext vp<[[PRED]]> to i32
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%0>, ir<%conv>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT: Successor(s): pred.load
 ; CHECK-EMPTY:
 ; CHECK:      <xVFxUF> pred.load: {
@@ -302,18 +318,20 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:   Successor(s): pred.load.if, pred.load.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.load.if:
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%lv.2> = load ir<%gep> (S->V)
 ; CHECK-NEXT:   Successor(s): pred.load.continue
 ; CHECK-EMPTY:
 ; CHECK:        pred.load.continue:
-; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%9> = ir<%lv.2>
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<[[REM:%.+]]> = ir<%rem>
+; CHECK-NEXT:     PHI-PREDICATED-INSTRUCTION vp<%10> = ir<%lv.2>
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT:   Successor(s): loop.1
+; CHECK-NEXT:   Successor(s): loop.2
 ; CHECK-EMPTY:
-; CHECK-NEXT:  loop.1:
-; CHECK-NEXT:    WIDEN ir<%add.1> = add ir<%conv>, ir<%rem>
-; CHECK-NEXT:    WIDEN-CAST ir<%conv.lv.2> = sext vp<%9> to i32
+; CHECK-NEXT:  loop.2:
+; CHECK-NEXT:    WIDEN ir<%add.1> = add ir<%conv>, vp<[[REM]]>
+; CHECK-NEXT:    WIDEN-CAST ir<%conv.lv.2> = sext vp<%10> to i32
 ; CHECK-NEXT:    WIDEN ir<%add> = add ir<%add.1>, ir<%conv.lv.2>
 ; CHECK-NEXT:  Successor(s): pred.store
 ; CHECK-EMPTY:
@@ -330,9 +348,9 @@ define void @sink_replicate_region_4_requires_split_at_end_of_block(i32 %x, ptr
 ; CHECK-NEXT:    pred.store.continue:
 ; CHECK-NEXT:    No successors
 ; CHECK-NEXT:  }
-; CHECK-NEXT:  Successor(s): loop.2
+; CHECK-NEXT:  Successor(s): loop.3
 ; CHECK-EMPTY:
-; CHECK:      loop.2:
+; CHECK:      loop.3:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
@@ -394,7 +412,6 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   ir<%iv> = WIDEN-INDUCTION ir<0>, ir<1>, vp<[[VF]]>
 ; CHECK-NEXT:   EMIT vp<[[MASK:%.+]]> = icmp ule ir<%iv>, vp<[[BTC]]>
 ; CHECK-NEXT:   EMIT vp<[[SPLICE:%.+]]> = first-order splice ir<%recur>, ir<%recur.next>
-; CHECK-NEXT:   WIDEN ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT: Successor(s): pred.store
 ; CHECK-EMPTY:
 ; CHECK-NEXT: <xVFxUF> pred.store: {
@@ -404,6 +421,7 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-EMPTY:
 ; CHECK-NEXT:   pred.store.if:
 ; CHECK-NEXT:     vp<[[STEPS:%.+]]> = SCALAR-STEPS vp<[[CAN_IV]]>, ir<1>
+; CHECK-NEXT:     REPLICATE ir<%rem> = srem vp<[[SPLICE]]>, ir<%x>
 ; CHECK-NEXT:     REPLICATE ir<%rem.div> = sdiv ir<20>, ir<%rem>
 ; CHECK-NEXT:     REPLICATE ir<%gep> = getelementptr ir<%ptr>, vp<[[STEPS]]>
 ; CHECK-NEXT:     REPLICATE store ir<%rem.div>, ir<%gep>
@@ -414,9 +432,9 @@ define void @sink_replicate_region_after_replicate_region(ptr %ptr, ptr noalias
 ; CHECK-NEXT:   pred.store.continue:
 ; CHECK-NEXT:   No successors
 ; CHECK-NEXT: }
-; CHECK-NEXT: Successor(s): loop.2
+; CHECK-NEXT: Successor(s): loop.3
 ; CHECK-EMPTY:
-; CHECK-NEXT: loop.2:
+; CHECK-NEXT: loop.3:
 ; CHECK-NEXT:   EMIT vp<[[CAN_IV_NEXT:%.+]]> = add nuw vp<[[CAN_IV]]>, vp<[[VFxUF]]>
 ; CHECK-NEXT:   EMIT branch-on-count vp<[[CAN_IV_NEXT]]>, vp<[[VEC_TC]]>
 ; CHECK-NEXT: No successors
diff --git a/llvm/test/Transforms/LoopVectorize/tail-folding-div.ll b/llvm/test/Transforms/LoopVectorize/tail-folding-div.ll
new file mode 100644
index 0000000000000..574cb3de6384d
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/tail-folding-div.ll
@@ -0,0 +1,550 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -S --passes=loop-vectorize -prefer-predicate-over-epilogue=predicate-dont-vectorize -force-vector-width=2 < %s | FileCheck %s
+
+; No predicate for sdiv because RHS has no masked-off lanes.
+define void @test_sdiv_variant_divisor_induction(ptr noalias %a, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_variant_divisor_induction(
+; CHECK-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i64> [ <i64 1, i64 2>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[OFFSET_IDX:%.*]] = add i64 1, [[INDEX]]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[OFFSET_IDX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[OFFSET_IDX]], 1
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[INDEX]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    [[VEC_IV:%.*]] = add <2 x i64> [[BROADCAST_SPLAT]], <i64 0, i64 1>
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp ule <2 x i64> [[VEC_IV]], splat (i64 1024)
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP3]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK:       [[PRED_LOAD_IF]]:
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP5:%.*]] = load i64, ptr [[TMP4]], align 4
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> poison, i64 [[TMP5]], i32 0
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE]]
+; CHECK:       [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP6]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP8]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2:.*]]
+; CHECK:       [[PRED_LOAD_IF1]]:
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP10:%.*]] = load i64, ptr [[TMP9]], align 4
+; CHECK-NEXT:    [[TMP11:%.*]] = insertelement <2 x i64> [[TMP7]], i64 [[TMP10]], i32 1
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK:       [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = phi <2 x i64> [ [[TMP7]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP11]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = sdiv <2 x i64> [[TMP12]], [[VEC_IND]]
+; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP14]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP15:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP16:%.*]] = extractelement <2 x i64> [[TMP13]], i32 0
+; CHECK-NEXT:    store i64 [[TMP16]], ptr [[TMP15]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP17]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP18:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP19:%.*]] = extractelement <2 x i64> [[TMP13]], i32 1
+; CHECK-NEXT:    store i64 [[TMP19]], ptr [[TMP18]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i64> [[VEC_IND]], splat (i64 2)
+; CHECK-NEXT:    [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP20]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP0:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 1, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, %iv
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1026
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; Predicate for sdiv because RHS have masked-off lanes.
+define void @test_sdiv_variant_divisor_load(ptr noalias %a, ptr noalias %b, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_variant_divisor_load(
+; CHECK-SAME: ptr noalias [[A:%.*]], ptr noalias [[B:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 0, i16 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp ule <2 x i16> [[VEC_IND]], splat (i16 1024)
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP3]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK:       [[PRED_LOAD_IF]]:
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP5:%.*]] = load i64, ptr [[TMP4]], align 4
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> poison, i64 [[TMP5]], i32 0
+; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr i64, ptr [[B]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP8:%.*]] = load i64, ptr [[TMP7]], align 4
+; CHECK-NEXT:    [[TMP9:%.*]] = insertelement <2 x i64> poison, i64 [[TMP8]], i32 0
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE]]
+; CHECK:       [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT:    [[TMP10:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP6]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP11:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP9]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP12:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP12]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2:.*]]
+; CHECK:       [[PRED_LOAD_IF1]]:
+; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP14:%.*]] = load i64, ptr [[TMP13]], align 4
+; CHECK-NEXT:    [[TMP15:%.*]] = insertelement <2 x i64> [[TMP10]], i64 [[TMP14]], i32 1
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr i64, ptr [[B]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP17:%.*]] = load i64, ptr [[TMP16]], align 4
+; CHECK-NEXT:    [[TMP18:%.*]] = insertelement <2 x i64> [[TMP11]], i64 [[TMP17]], i32 1
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK:       [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP19:%.*]] = phi <2 x i64> [ [[TMP10]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP15]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP20:%.*]] = phi <2 x i64> [ [[TMP11]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP18]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP21:%.*]] = select <2 x i1> [[TMP2]], <2 x i64> [[TMP20]], <2 x i64> splat (i64 1)
+; CHECK-NEXT:    [[TMP22:%.*]] = sdiv <2 x i64> [[TMP19]], [[TMP21]]
+; CHECK-NEXT:    [[TMP23:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP23]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP24:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP25:%.*]] = extractelement <2 x i64> [[TMP22]], i32 0
+; CHECK-NEXT:    store i64 [[TMP25]], ptr [[TMP24]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP26:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP26]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP27:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP28:%.*]] = extractelement <2 x i64> [[TMP22]], i32 1
+; CHECK-NEXT:    store i64 [[TMP28]], ptr [[TMP27]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[TMP29:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP29]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP3:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %b.gep = getelementptr i64, ptr %b, i64 %iv
+  %1 = load i64, ptr %b.gep
+  %2 = sdiv i64 %0, %1
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1025
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; Predicate for sdiv because RHS may be -1.
+define void @test_sdiv_invariant_divisor_nonconst(ptr noalias %a, i64 %b, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_invariant_divisor_nonconst(
+; CHECK-SAME: ptr noalias [[A:%.*]], i64 [[B:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[B]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 0, i16 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp ule <2 x i16> [[VEC_IND]], splat (i16 1024)
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP3]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK:       [[PRED_LOAD_IF]]:
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP5:%.*]] = load i64, ptr [[TMP4]], align 4
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> poison, i64 [[TMP5]], i32 0
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE]]
+; CHECK:       [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP6]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP8]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2:.*]]
+; CHECK:       [[PRED_LOAD_IF1]]:
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP10:%.*]] = load i64, ptr [[TMP9]], align 4
+; CHECK-NEXT:    [[TMP11:%.*]] = insertelement <2 x i64> [[TMP7]], i64 [[TMP10]], i32 1
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK:       [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = phi <2 x i64> [ [[TMP7]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP11]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = select <2 x i1> [[TMP2]], <2 x i64> [[BROADCAST_SPLAT]], <2 x i64> splat (i64 1)
+; CHECK-NEXT:    [[TMP14:%.*]] = sdiv <2 x i64> [[TMP12]], [[TMP13]]
+; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP15]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x i64> [[TMP14]], i32 0
+; CHECK-NEXT:    store i64 [[TMP17]], ptr [[TMP16]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP18:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP18]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP20:%.*]] = extractelement <2 x i64> [[TMP14]], i32 1
+; CHECK-NEXT:    store i64 [[TMP20]], ptr [[TMP19]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[TMP21:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP21]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, %b
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1025
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; Predicate for sdiv because RHS is -1.
+define void @test_sdiv_invariant_divisor_minusone(ptr noalias %a, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_invariant_divisor_minusone(
+; CHECK-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 0, i16 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp ule <2 x i16> [[VEC_IND]], splat (i16 1024)
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP3]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK:       [[PRED_LOAD_IF]]:
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP5:%.*]] = load i64, ptr [[TMP4]], align 4
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> poison, i64 [[TMP5]], i32 0
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE]]
+; CHECK:       [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP6]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP8]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2:.*]]
+; CHECK:       [[PRED_LOAD_IF1]]:
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP10:%.*]] = load i64, ptr [[TMP9]], align 4
+; CHECK-NEXT:    [[TMP11:%.*]] = insertelement <2 x i64> [[TMP7]], i64 [[TMP10]], i32 1
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK:       [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = phi <2 x i64> [ [[TMP7]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP11]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = select <2 x i1> [[TMP2]], <2 x i64> splat (i64 -1), <2 x i64> splat (i64 1)
+; CHECK-NEXT:    [[TMP14:%.*]] = sdiv <2 x i64> [[TMP12]], [[TMP13]]
+; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP15]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x i64> [[TMP14]], i32 0
+; CHECK-NEXT:    store i64 [[TMP17]], ptr [[TMP16]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP18:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP18]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP20:%.*]] = extractelement <2 x i64> [[TMP14]], i32 1
+; CHECK-NEXT:    store i64 [[TMP20]], ptr [[TMP19]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[TMP21:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP21]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, -1
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1025
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; No predicate for sdiv because RHS is 3.
+define void @test_sdiv_invariant_divisor_safeimm(ptr noalias %a, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_invariant_divisor_safeimm(
+; CHECK-SAME: ptr noalias [[A:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 0, i16 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = icmp ule <2 x i16> [[VEC_IND]], splat (i16 1024)
+; CHECK-NEXT:    [[TMP3:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP3]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK:       [[PRED_LOAD_IF]]:
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP5:%.*]] = load i64, ptr [[TMP4]], align 4
+; CHECK-NEXT:    [[TMP6:%.*]] = insertelement <2 x i64> poison, i64 [[TMP5]], i32 0
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE]]
+; CHECK:       [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP6]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP8:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP8]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2:.*]]
+; CHECK:       [[PRED_LOAD_IF1]]:
+; CHECK-NEXT:    [[TMP9:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP10:%.*]] = load i64, ptr [[TMP9]], align 4
+; CHECK-NEXT:    [[TMP11:%.*]] = insertelement <2 x i64> [[TMP7]], i64 [[TMP10]], i32 1
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK:       [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP12:%.*]] = phi <2 x i64> [ [[TMP7]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP11]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP13:%.*]] = sdiv <2 x i64> [[TMP12]], splat (i64 3)
+; CHECK-NEXT:    [[TMP14:%.*]] = extractelement <2 x i1> [[TMP2]], i32 0
+; CHECK-NEXT:    br i1 [[TMP14]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP15:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP0]]
+; CHECK-NEXT:    [[TMP16:%.*]] = extractelement <2 x i64> [[TMP13]], i32 0
+; CHECK-NEXT:    store i64 [[TMP16]], ptr [[TMP15]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x i1> [[TMP2]], i32 1
+; CHECK-NEXT:    br i1 [[TMP17]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP18:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP19:%.*]] = extractelement <2 x i64> [[TMP13]], i32 1
+; CHECK-NEXT:    store i64 [[TMP19]], ptr [[TMP18]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP20]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %0, 3
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1025
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; No predicate for sdiv because LHS & RHS has no masked-off lanes.
+define void @test_sdiv_variant_dividend_induction(i64 %a, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_variant_dividend_induction(
+; CHECK-SAME: i64 [[A:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[A]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE2:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i64> [ <i64 0, i64 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE2]] ]
+; CHECK-NEXT:    [[TMP0:%.*]] = icmp ule <2 x i64> [[VEC_IND]], splat (i64 1024)
+; CHECK-NEXT:    [[TMP1:%.*]] = sdiv <2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP2:%.*]] = extractelement <2 x i1> [[TMP0]], i32 0
+; CHECK-NEXT:    br i1 [[TMP2]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP3:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP4:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP3]]
+; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <2 x i64> [[TMP1]], i32 0
+; CHECK-NEXT:    store i64 [[TMP5]], ptr [[TMP4]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP6:%.*]] = extractelement <2 x i1> [[TMP0]], i32 1
+; CHECK-NEXT:    br i1 [[TMP6]], label %[[PRED_STORE_IF1:.*]], label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_IF1]]:
+; CHECK-NEXT:    [[TMP7:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP8:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP7]]
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i64> [[TMP1]], i32 1
+; CHECK-NEXT:    store i64 [[TMP9]], ptr [[TMP8]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE2]]
+; CHECK:       [[PRED_STORE_CONTINUE2]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i64> [[VEC_IND]], splat (i64 2)
+; CHECK-NEXT:    [[TMP10:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP10]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %2 = sdiv i64 %iv, %a
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %2, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1025
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+
+; No predicate for sdiv because both LHS & RHS have no masked-off lanes.
+define void @test_sdiv_both_invariant_nonconst(ptr noalias %a, i64 %b, i64 %b2, ptr noalias %c) {
+; CHECK-LABEL: define void @test_sdiv_both_invariant_nonconst(
+; CHECK-SAME: ptr noalias [[A:%.*]], i64 [[B:%.*]], i64 [[B2:%.*]], ptr noalias [[C:%.*]]) {
+; CHECK-NEXT:  [[LOOP_PREHEADER:.*:]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
+; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP0:%.*]] = sdiv i64 [[B]], [[B2]]
+; CHECK-NEXT:    [[BROADCAST_SPLATINSERT:%.*]] = insertelement <2 x i64> poison, i64 [[TMP0]], i64 0
+; CHECK-NEXT:    [[BROADCAST_SPLAT:%.*]] = shufflevector <2 x i64> [[BROADCAST_SPLATINSERT]], <2 x i64> poison, <2 x i32> zeroinitializer
+; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
+; CHECK:       [[VECTOR_BODY]]:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE4:.*]] ]
+; CHECK-NEXT:    [[VEC_IND:%.*]] = phi <2 x i16> [ <i16 0, i16 1>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE4]] ]
+; CHECK-NEXT:    [[TMP1:%.*]] = add i64 [[INDEX]], 0
+; CHECK-NEXT:    [[TMP2:%.*]] = add i64 [[INDEX]], 1
+; CHECK-NEXT:    [[TMP3:%.*]] = icmp ule <2 x i16> [[VEC_IND]], splat (i16 1024)
+; CHECK-NEXT:    [[TMP4:%.*]] = extractelement <2 x i1> [[TMP3]], i32 0
+; CHECK-NEXT:    br i1 [[TMP4]], label %[[PRED_LOAD_IF:.*]], label %[[PRED_LOAD_CONTINUE:.*]]
+; CHECK:       [[PRED_LOAD_IF]]:
+; CHECK-NEXT:    [[TMP5:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP6:%.*]] = load i64, ptr [[TMP5]], align 4
+; CHECK-NEXT:    [[TMP7:%.*]] = insertelement <2 x i64> poison, i64 [[TMP6]], i32 0
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE]]
+; CHECK:       [[PRED_LOAD_CONTINUE]]:
+; CHECK-NEXT:    [[TMP8:%.*]] = phi <2 x i64> [ poison, %[[VECTOR_BODY]] ], [ [[TMP7]], %[[PRED_LOAD_IF]] ]
+; CHECK-NEXT:    [[TMP9:%.*]] = extractelement <2 x i1> [[TMP3]], i32 1
+; CHECK-NEXT:    br i1 [[TMP9]], label %[[PRED_LOAD_IF1:.*]], label %[[PRED_LOAD_CONTINUE2:.*]]
+; CHECK:       [[PRED_LOAD_IF1]]:
+; CHECK-NEXT:    [[TMP10:%.*]] = getelementptr i64, ptr [[A]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP11:%.*]] = load i64, ptr [[TMP10]], align 4
+; CHECK-NEXT:    [[TMP12:%.*]] = insertelement <2 x i64> [[TMP8]], i64 [[TMP11]], i32 1
+; CHECK-NEXT:    br label %[[PRED_LOAD_CONTINUE2]]
+; CHECK:       [[PRED_LOAD_CONTINUE2]]:
+; CHECK-NEXT:    [[TMP13:%.*]] = phi <2 x i64> [ [[TMP8]], %[[PRED_LOAD_CONTINUE]] ], [ [[TMP12]], %[[PRED_LOAD_IF1]] ]
+; CHECK-NEXT:    [[TMP14:%.*]] = add <2 x i64> [[TMP13]], [[BROADCAST_SPLAT]]
+; CHECK-NEXT:    [[TMP15:%.*]] = extractelement <2 x i1> [[TMP3]], i32 0
+; CHECK-NEXT:    br i1 [[TMP15]], label %[[PRED_STORE_IF:.*]], label %[[PRED_STORE_CONTINUE:.*]]
+; CHECK:       [[PRED_STORE_IF]]:
+; CHECK-NEXT:    [[TMP16:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP1]]
+; CHECK-NEXT:    [[TMP17:%.*]] = extractelement <2 x i64> [[TMP14]], i32 0
+; CHECK-NEXT:    store i64 [[TMP17]], ptr [[TMP16]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE]]
+; CHECK:       [[PRED_STORE_CONTINUE]]:
+; CHECK-NEXT:    [[TMP18:%.*]] = extractelement <2 x i1> [[TMP3]], i32 1
+; CHECK-NEXT:    br i1 [[TMP18]], label %[[PRED_STORE_IF3:.*]], label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_IF3]]:
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr i64, ptr [[C]], i64 [[TMP2]]
+; CHECK-NEXT:    [[TMP20:%.*]] = extractelement <2 x i64> [[TMP14]], i32 1
+; CHECK-NEXT:    store i64 [[TMP20]], ptr [[TMP19]], align 4
+; CHECK-NEXT:    br label %[[PRED_STORE_CONTINUE4]]
+; CHECK:       [[PRED_STORE_CONTINUE4]]:
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
+; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <2 x i16> [[VEC_IND]], splat (i16 2)
+; CHECK-NEXT:    [[TMP21:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1026
+; CHECK-NEXT:    br i1 [[TMP21]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK:       [[MIDDLE_BLOCK]]:
+; CHECK-NEXT:    br label %[[EXIT:.*]]
+; CHECK:       [[EXIT]]:
+; CHECK-NEXT:    ret void
+;
+loop.preheader:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ %iv.next, %loop ], [ 0, %loop.preheader ]
+  %a.gep = getelementptr i64, ptr %a, i64 %iv
+  %0 = load i64, ptr %a.gep
+  %2 = sdiv i64 %b, %b2
+  %3 = add i64 %0, %2
+  %c.gep = getelementptr i64, ptr %c, i64 %iv
+  store i64 %3, ptr %c.gep
+  %iv.next = add i64 %iv, 1
+  %done = icmp eq i64 %iv.next, 1025
+  br i1 %done, label %exit, label %loop
+
+exit:
+  ret void
+}
+;.
+; CHECK: [[LOOP0]] = distinct !{[[LOOP0]], [[META1:![0-9]+]], [[META2:![0-9]+]]}
+; CHECK: [[META1]] = !{!"llvm.loop.isvectorized", i32 1}
+; CHECK: [[META2]] = !{!"llvm.loop.unroll.runtime.disable"}
+; CHECK: [[LOOP3]] = distinct !{[[LOOP3]], [[META1]], [[META2]]}
+; CHECK: [[LOOP4]] = distinct !{[[LOOP4]], [[META1]], [[META2]]}
+; CHECK: [[LOOP5]] = distinct !{[[LOOP5]], [[META1]], [[META2]]}
+; CHECK: [[LOOP6]] = distinct !{[[LOOP6]], [[META1]], [[META2]]}
+; CHECK: [[LOOP7]] = distinct !{[[LOOP7]], [[META1]], [[META2]]}
+; CHECK: [[LOOP8]] = distinct !{[[LOOP8]], [[META1]], [[META2]]}
+;.

>From 0f46a3b2f14511772b3e38d6d802f2a2283087e2 Mon Sep 17 00:00:00 2001
From: ShihPo Hung <shihpo.hung at sifive.com>
Date: Wed, 10 Dec 2025 22:43:12 -0800
Subject: [PATCH 6/6] Refine comments

---
 llvm/lib/Transforms/Vectorize/LoopVectorize.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index ab3adb9dda9ba..7688b2cb2a044 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2892,15 +2892,15 @@ bool LoopVectorizationCostModel::isPredicatedInst(Instruction *I) const {
     APInt MinusOne = APInt::getAllOnes(Bits);
     bool MayBeNegOne = SE.getSignedRange(RHSSC).contains(MinusOne);
 
-    // No predicate if RHS have no masked-off lanes and not -1.
+    // No predicate if RHS have no poison in masked-off lanes and not -1.
     if (isa<SCEVAddRecExpr>(RHSSC) && !MayBeNegOne)
       return false;
 
-    // Prediate if RHS may have masked-off lanes.
+    // Prediate if RHS may have poison in masked-off lanes.
     if (!Legal->isInvariant(RHS))
       return true;
 
-    // No predicate if LHS have no masked-off lanes and not INT_MIN.
+    // No predicate if LHS have no poison in masked-off lanes and not INT_MIN.
     if (isa<SCEVAddRecExpr>(LHSSC) &&
         !SE.getSignedRangeMin(SE.getSCEV(LHS)).isMinSignedValue())
       return false;



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