[llvm] [LV] Use SCEV::getElementCount in selectEpilogueVectorizationFactor. (PR #150018)

via llvm-commits llvm-commits at lists.llvm.org
Tue Jul 22 06:16:34 PDT 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Florian Hahn (fhahn)

<details>
<summary>Changes</summary>

Follow-up to https://github.com/llvm/llvm-project/pull/149789 to use getElementCount to compute the remaining iterations in selectEpilogueVectrizationFactor.

---

Patch is 21.46 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/150018.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+10-12) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/sve-epilog-vect.ll (+147-38) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 773c1559ec679..cda451ca0f751 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -4479,19 +4479,17 @@ VectorizationFactor LoopVectorizationPlanner::selectEpilogueVectorizationFactor(
   Type *TCType = Legal->getWidestInductionType();
   const SCEV *RemainingIterations = nullptr;
   unsigned MaxTripCount = 0;
-  if (MainLoopVF.isFixed()) {
-    // TODO: extend to support scalable VFs.
-    const SCEV *TC = vputils::getSCEVExprForVPValue(
-        getPlanFor(MainLoopVF).getTripCount(), SE);
-    assert(!isa<SCEVCouldNotCompute>(TC) &&
-           "Trip count SCEV must be computable");
-    RemainingIterations = SE.getURemExpr(
-        TC, SE.getConstant(TCType, MainLoopVF.getFixedValue() * IC));
-
-    // No iterations left to process in the epilogue.
-    if (RemainingIterations->isZero())
-      return Result;
+  const SCEV *TC =
+      vputils::getSCEVExprForVPValue(getPlanFor(MainLoopVF).getTripCount(), SE);
+  assert(!isa<SCEVCouldNotCompute>(TC) && "Trip count SCEV must be computable");
+  RemainingIterations =
+      SE.getURemExpr(TC, SE.getElementCount(TCType, MainLoopVF * IC));
+
+  // No iterations left to process in the epilogue.
+  if (RemainingIterations->isZero())
+    return Result;
 
+  if (MainLoopVF.isFixed()) {
     MaxTripCount = MainLoopVF.getFixedValue() * IC - 1;
     if (SE.isKnownPredicate(CmpInst::ICMP_ULT, RemainingIterations,
                             SE.getConstant(TCType, MaxTripCount))) {
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/sve-epilog-vect.ll b/llvm/test/Transforms/LoopVectorize/AArch64/sve-epilog-vect.ll
index 520937454ce5a..8de0fde132ad3 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/sve-epilog-vect.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/sve-epilog-vect.ll
@@ -152,6 +152,107 @@ exit:
   ret void
 }
 
+define void @main_vf_vscale_x_2_no_epi_iteration(ptr %A) #0 vscale_range(8, 8) {
+; CHECK-LABEL: @main_vf_vscale_x_2_no_epi_iteration(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP1:%.*]] = mul nuw i64 [[TMP0]], 4
+; CHECK-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK:       vector.ph:
+; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 4
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; CHECK-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 4
+; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK:       vector.body:
+; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i64, ptr [[A:%.*]], i64 [[INDEX]]
+; CHECK-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[TMP6]], i32 0
+; CHECK-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-NEXT:    [[TMP9:%.*]] = mul nuw i64 [[TMP8]], 2
+; CHECK-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i64, ptr [[TMP6]], i64 [[TMP9]]
+; CHECK-NEXT:    store <vscale x 2 x i64> splat (i64 1), ptr [[TMP7]], align 1
+; CHECK-NEXT:    store <vscale x 2 x i64> splat (i64 1), ptr [[TMP10]], align 1
+; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
+; CHECK-NEXT:    [[TMP11:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK:       middle.block:
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH]]
+; CHECK:       scalar.ph:
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ]
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+;
+; CHECK-VF8-LABEL: @main_vf_vscale_x_2_no_epi_iteration(
+; CHECK-VF8-NEXT:  iter.check:
+; CHECK-VF8-NEXT:    br i1 false, label [[VEC_EPILOG_SCALAR_PH:%.*]], label [[VECTOR_MAIN_LOOP_ITER_CHECK:%.*]]
+; CHECK-VF8:       vector.main.loop.iter.check:
+; CHECK-VF8-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-VF8-NEXT:    [[TMP1:%.*]] = mul nuw i64 [[TMP0]], 4
+; CHECK-VF8-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
+; CHECK-VF8-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[VEC_EPILOG_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK-VF8:       vector.ph:
+; CHECK-VF8-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-VF8-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 4
+; CHECK-VF8-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
+; CHECK-VF8-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; CHECK-VF8-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-VF8-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 4
+; CHECK-VF8-NEXT:    br label [[VECTOR_BODY:%.*]]
+; CHECK-VF8:       vector.body:
+; CHECK-VF8-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
+; CHECK-VF8-NEXT:    [[TMP6:%.*]] = getelementptr inbounds i64, ptr [[A:%.*]], i64 [[INDEX]]
+; CHECK-VF8-NEXT:    [[TMP7:%.*]] = getelementptr inbounds i64, ptr [[TMP6]], i32 0
+; CHECK-VF8-NEXT:    [[TMP8:%.*]] = call i64 @llvm.vscale.i64()
+; CHECK-VF8-NEXT:    [[TMP9:%.*]] = mul nuw i64 [[TMP8]], 2
+; CHECK-VF8-NEXT:    [[TMP10:%.*]] = getelementptr inbounds i64, ptr [[TMP6]], i64 [[TMP9]]
+; CHECK-VF8-NEXT:    store <vscale x 2 x i64> splat (i64 1), ptr [[TMP7]], align 1
+; CHECK-VF8-NEXT:    store <vscale x 2 x i64> splat (i64 1), ptr [[TMP10]], align 1
+; CHECK-VF8-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
+; CHECK-VF8-NEXT:    [[TMP11:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
+; CHECK-VF8-NEXT:    br i1 [[TMP11]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-VF8:       middle.block:
+; CHECK-VF8-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; CHECK-VF8-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[VEC_EPILOG_ITER_CHECK:%.*]]
+; CHECK-VF8:       vec.epilog.iter.check:
+; CHECK-VF8-NEXT:    [[N_VEC_REMAINING:%.*]] = sub i64 1024, [[N_VEC]]
+; CHECK-VF8-NEXT:    [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_VEC_REMAINING]], 8
+; CHECK-VF8-NEXT:    br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]]
+; CHECK-VF8:       vec.epilog.ph:
+; CHECK-VF8-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
+; CHECK-VF8-NEXT:    br label [[VEC_EPILOG_VECTOR_BODY:%.*]]
+; CHECK-VF8:       vec.epilog.vector.body:
+; CHECK-VF8-NEXT:    [[INDEX1:%.*]] = phi i64 [ [[VEC_EPILOG_RESUME_VAL]], [[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT2:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
+; CHECK-VF8-NEXT:    [[TMP12:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX1]]
+; CHECK-VF8-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i64, ptr [[TMP12]], i32 0
+; CHECK-VF8-NEXT:    store <8 x i64> splat (i64 1), ptr [[TMP13]], align 1
+; CHECK-VF8-NEXT:    [[INDEX_NEXT2]] = add nuw i64 [[INDEX1]], 8
+; CHECK-VF8-NEXT:    [[TMP14:%.*]] = icmp eq i64 [[INDEX_NEXT2]], 1024
+; CHECK-VF8-NEXT:    br i1 [[TMP14]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-VF8:       vec.epilog.middle.block:
+; CHECK-VF8-NEXT:    br i1 true, label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
+; CHECK-VF8:       vec.epilog.scalar.ph:
+; CHECK-VF8-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 1024, [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[ITER_CHECK:%.*]] ]
+; CHECK-VF8-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK-VF8:       for.body:
+;
+entry:
+  br label %for.body
+
+for.body:
+  %iv = phi i64 [ 0, %entry ], [ %iv.next, %for.body ]
+  %arrayidx = getelementptr inbounds i64, ptr %A, i64 %iv
+  store i64 1, ptr %arrayidx, align 1
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp ne i64 %iv.next, 1024
+  br i1 %exitcond, label %for.body, label %exit
+
+exit:
+  ret void
+}
 
 ; DEBUG: LV: Checking a loop in 'main_vf_vscale_x_2'
 ; DEBUG: Create Skeleton for epilogue vectorized loop (first pass)
@@ -167,20 +268,21 @@ exit:
 ; fixed-width VF=8 for the epilogue if the vectors are known to be
 ; sufficiently wide. This information can be deduced from vscale_range or
 ; VScaleForTuning (set by mcpu/mtune).
-define void @main_vf_vscale_x_2(ptr %A) #0 vscale_range(8, 8) {
+define void @main_vf_vscale_x_2(ptr %A, i64 %n) #0 vscale_range(8, 8) {
 ; CHECK-LABEL: @main_vf_vscale_x_2(
 ; CHECK-NEXT:  iter.check:
-; CHECK-NEXT:    br i1 false, label [[VEC_EPILOG_SCALAR_PH:%.*]], label [[VECTOR_MAIN_LOOP_ITER_CHECK:%.*]]
+; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N:%.*]], 8
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH:%.*]], label [[VECTOR_MAIN_LOOP_ITER_CHECK:%.*]]
 ; CHECK:       vector.main.loop.iter.check:
 ; CHECK-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP1:%.*]] = mul nuw i64 [[TMP0]], 4
-; CHECK-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
-; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[VEC_EPILOG_PH:%.*]], label [[VECTOR_PH:%.*]]
+; CHECK-NEXT:    [[MIN_ITERS_CHECK1:%.*]] = icmp ult i64 [[N]], [[TMP1]]
+; CHECK-NEXT:    br i1 [[MIN_ITERS_CHECK1]], label [[VEC_EPILOG_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; CHECK:       vector.ph:
 ; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 4
-; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
-; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; CHECK-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], [[TMP3]]
+; CHECK-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
 ; CHECK-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 4
 ; CHECK-NEXT:    br label [[VECTOR_BODY:%.*]]
@@ -195,45 +297,49 @@ define void @main_vf_vscale_x_2(ptr %A) #0 vscale_range(8, 8) {
 ; CHECK-NEXT:    store <vscale x 2 x i64> splat (i64 1), ptr [[TMP17]], align 1
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
 ; CHECK-NEXT:    [[TMP18:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
 ; CHECK:       middle.block:
-; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
-; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[VEC_EPILOG_ITER_CHECK:%.*]]
+; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
+; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[SCALAR_PH:%.*]]
 ; CHECK:       vec.epilog.iter.check:
-; CHECK-NEXT:    [[N_VEC_REMAINING:%.*]] = sub i64 1024, [[N_VEC]]
+; CHECK-NEXT:    [[N_VEC_REMAINING:%.*]] = sub i64 [[N]], [[N_VEC]]
 ; CHECK-NEXT:    [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_VEC_REMAINING]], 8
 ; CHECK-NEXT:    br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]]
 ; CHECK:       vec.epilog.ph:
-; CHECK-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
-; CHECK-NEXT:    br label [[VEC_EPILOG_VECTOR_BODY:%.*]]
+; CHECK-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[SCALAR_PH]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
+; CHECK-NEXT:    [[N_MOD_VF2:%.*]] = urem i64 [[N]], 8
+; CHECK-NEXT:    [[N_VEC3:%.*]] = sub i64 [[N]], [[N_MOD_VF2]]
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
 ; CHECK:       vec.epilog.vector.body:
-; CHECK-NEXT:    [[INDEX1:%.*]] = phi i64 [ [[VEC_EPILOG_RESUME_VAL]], [[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT2:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
-; CHECK-NEXT:    [[TMP20:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX1]]
-; CHECK-NEXT:    [[TMP21:%.*]] = getelementptr inbounds i64, ptr [[TMP20]], i32 0
-; CHECK-NEXT:    store <8 x i64> splat (i64 1), ptr [[TMP21]], align 1
-; CHECK-NEXT:    [[INDEX_NEXT2]] = add nuw i64 [[INDEX1]], 8
-; CHECK-NEXT:    [[TMP22:%.*]] = icmp eq i64 [[INDEX_NEXT2]], 1024
-; CHECK-NEXT:    br i1 [[TMP22]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-NEXT:    [[INDEX4:%.*]] = phi i64 [ [[VEC_EPILOG_RESUME_VAL]], [[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT5:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[TMP19:%.*]] = getelementptr inbounds i64, ptr [[A]], i64 [[INDEX4]]
+; CHECK-NEXT:    [[TMP13:%.*]] = getelementptr inbounds i64, ptr [[TMP19]], i32 0
+; CHECK-NEXT:    store <8 x i64> splat (i64 1), ptr [[TMP13]], align 1
+; CHECK-NEXT:    [[INDEX_NEXT5]] = add nuw i64 [[INDEX4]], 8
+; CHECK-NEXT:    [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT5]], [[N_VEC3]]
+; CHECK-NEXT:    br i1 [[TMP20]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[FOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
 ; CHECK:       vec.epilog.middle.block:
-; CHECK-NEXT:    br i1 true, label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
+; CHECK-NEXT:    [[CMP_N6:%.*]] = icmp eq i64 [[N]], [[N_VEC3]]
+; CHECK-NEXT:    br i1 [[CMP_N6]], label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
 ; CHECK:       vec.epilog.scalar.ph:
-; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 1024, [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[ITER_CHECK:%.*]] ]
-; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC3]], [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[N_VEC]], [[SCALAR_PH]] ], [ 0, [[ITER_CHECK:%.*]] ]
+; CHECK-NEXT:    br label [[FOR_BODY1:%.*]]
 ; CHECK:       for.body:
 ;
 ; CHECK-VF8-LABEL: @main_vf_vscale_x_2(
 ; CHECK-VF8-NEXT:  iter.check:
-; CHECK-VF8-NEXT:    br i1 false, label [[VEC_EPILOG_SCALAR_PH:%.*]], label [[VECTOR_MAIN_LOOP_ITER_CHECK:%.*]]
+; CHECK-VF8-NEXT:    [[MIN_ITERS_CHECK1:%.*]] = icmp ult i64 [[N:%.*]], 8
+; CHECK-VF8-NEXT:    br i1 [[MIN_ITERS_CHECK1]], label [[VEC_EPILOG_SCALAR_PH:%.*]], label [[VECTOR_MAIN_LOOP_ITER_CHECK:%.*]]
 ; CHECK-VF8:       vector.main.loop.iter.check:
 ; CHECK-VF8-NEXT:    [[TMP0:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-VF8-NEXT:    [[TMP1:%.*]] = mul nuw i64 [[TMP0]], 4
-; CHECK-VF8-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 1024, [[TMP1]]
+; CHECK-VF8-NEXT:    [[MIN_ITERS_CHECK:%.*]] = icmp ult i64 [[N]], [[TMP1]]
 ; CHECK-VF8-NEXT:    br i1 [[MIN_ITERS_CHECK]], label [[VEC_EPILOG_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; CHECK-VF8:       vector.ph:
 ; CHECK-VF8-NEXT:    [[TMP2:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-VF8-NEXT:    [[TMP3:%.*]] = mul nuw i64 [[TMP2]], 4
-; CHECK-VF8-NEXT:    [[N_MOD_VF:%.*]] = urem i64 1024, [[TMP3]]
-; CHECK-VF8-NEXT:    [[N_VEC:%.*]] = sub i64 1024, [[N_MOD_VF]]
+; CHECK-VF8-NEXT:    [[N_MOD_VF:%.*]] = urem i64 [[N]], [[TMP3]]
+; CHECK-VF8-NEXT:    [[N_VEC:%.*]] = sub i64 [[N]], [[N_MOD_VF]]
 ; CHECK-VF8-NEXT:    [[TMP4:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-VF8-NEXT:    [[TMP5:%.*]] = mul nuw i64 [[TMP4]], 4
 ; CHECK-VF8-NEXT:    br label [[VECTOR_BODY:%.*]]
@@ -248,16 +354,18 @@ define void @main_vf_vscale_x_2(ptr %A) #0 vscale_range(8, 8) {
 ; CHECK-VF8-NEXT:    store <vscale x 2 x i64> splat (i64 1), ptr [[TMP17]], align 1
 ; CHECK-VF8-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP5]]
 ; CHECK-VF8-NEXT:    [[TMP18:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-VF8-NEXT:    br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
+; CHECK-VF8-NEXT:    br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
 ; CHECK-VF8:       middle.block:
-; CHECK-VF8-NEXT:    [[CMP_N:%.*]] = icmp eq i64 1024, [[N_VEC]]
+; CHECK-VF8-NEXT:    [[CMP_N:%.*]] = icmp eq i64 [[N]], [[N_VEC]]
 ; CHECK-VF8-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[VEC_EPILOG_ITER_CHECK:%.*]]
 ; CHECK-VF8:       vec.epilog.iter.check:
-; CHECK-VF8-NEXT:    [[N_VEC_REMAINING:%.*]] = sub i64 1024, [[N_VEC]]
+; CHECK-VF8-NEXT:    [[N_VEC_REMAINING:%.*]] = sub i64 [[N]], [[N_VEC]]
 ; CHECK-VF8-NEXT:    [[MIN_EPILOG_ITERS_CHECK:%.*]] = icmp ult i64 [[N_VEC_REMAINING]], 8
 ; CHECK-VF8-NEXT:    br i1 [[MIN_EPILOG_ITERS_CHECK]], label [[VEC_EPILOG_SCALAR_PH]], label [[VEC_EPILOG_PH]]
 ; CHECK-VF8:       vec.epilog.ph:
 ; CHECK-VF8-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_MAIN_LOOP_ITER_CHECK]] ]
+; CHECK-VF8-NEXT:    [[N_MOD_VF2:%.*]] = urem i64 [[N]], 8
+; CHECK-VF8-NEXT:    [[N_VEC3:%.*]] = sub i64 [[N]], [[N_MOD_VF2]]
 ; CHECK-VF8-NEXT:    br label [[VEC_EPILOG_VECTOR_BODY:%.*]]
 ; CHECK-VF8:       vec.epilog.vector.body:
 ; CHECK-VF8-NEXT:    [[INDEX1:%.*]] = phi i64 [ [[VEC_EPILOG_RESUME_VAL]], [[VEC_EPILOG_PH]] ], [ [[INDEX_NEXT2:%.*]], [[VEC_EPILOG_VECTOR_BODY]] ]
@@ -265,12 +373,13 @@ define void @main_vf_vscale_x_2(ptr %A) #0 vscale_range(8, 8) {
 ; CHECK-VF8-NEXT:    [[TMP21:%.*]] = getelementptr inbounds i64, ptr [[TMP20]], i32 0
 ; CHECK-VF8-NEXT:    store <8 x i64> splat (i64 1), ptr [[TMP21]], align 1
 ; CHECK-VF8-NEXT:    [[INDEX_NEXT2]] = add nuw i64 [[INDEX1]], 8
-; CHECK-VF8-NEXT:    [[TMP22:%.*]] = icmp eq i64 [[INDEX_NEXT2]], 1024
-; CHECK-VF8-NEXT:    br i1 [[TMP22]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-VF8-NEXT:    [[TMP19:%.*]] = icmp eq i64 [[INDEX_NEXT2]], [[N_VEC3]]
+; CHECK-VF8-NEXT:    br i1 [[TMP19]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
 ; CHECK-VF8:       vec.epilog.middle.block:
-; CHECK-VF8-NEXT:    br i1 true, label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
+; CHECK-VF8-NEXT:    [[CMP_N6:%.*]] = icmp eq i64 [[N]], [[N_VEC3]]
+; CHECK-VF8-NEXT:    br i1 [[CMP_N6]], label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
 ; CHECK-VF8:       vec.epilog.scalar.ph:
-; CHECK-VF8-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ 1024, [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[ITER_CHECK:%.*]] ]
+; CHECK-VF8-NEXT:    [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC3]], [[VEC_EPILOG_MIDDLE_BLOCK]] ], [ [[N_VEC]], [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[ITER_CHECK:%.*]] ]
 ; CHECK-VF8-NEXT:    br label [[FOR_BODY:%.*]]
 ; CHECK-VF8:       for.body:
 ;
@@ -282,7 +391,7 @@ for.body:
   %arrayidx = getelementptr inbounds i64, ptr %A, i64 %iv
   store i64 1, ptr %arrayidx, align 1
   %iv.next = add nuw nsw i64 %iv, 1
-  %exitcond = icmp ne i64 %iv.next, 1024
+  %exitcond = icmp ne i64 %iv.next, %n
   br i1 %exitcond, label %for.body, label %exit
 
 exit:
@@ -322,7 +431,7 @@ define void @test_pr57912_pointer_induction(ptr %start) #0 {
 ; CHECK-NEXT:    store <vscale x 16 x i8> zeroinitializer, ptr [[TMP19]], align 1
 ; CHECK-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP7]]
 ; CHECK-NEXT:    [[TMP20:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT:    br i1 [[TMP20]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP8:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP20]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP10:![0-9]+]]
 ; CHECK:       middle.block:
 ; CHECK-NEXT:    [[CMP_N:%.*]] = icmp eq i64 10000, [[N_VEC]]
 ; CHECK-NEXT:    br i1 [[CMP_N]], label [[EXIT:%.*]], label [[VEC_EPILOG_ITER_CHECK:%.*]]
@@ -350,7 +459,7 @@ define void @test_pr57912_pointer_induction(ptr %start) #0 {
 ; CHECK-NEXT:    store <vscale x 8 x i8> zeroinitializer, ptr [[TMP29]], align 1
 ; CHECK-NEXT:    [[INDEX_NEXT8]] = add nuw i64 [[INDEX7]], [[TMP26]]
 ; CHECK-NEXT:    [[TMP30:%.*]] = icmp eq i64 [[INDEX_NEXT8]], [[N_VEC3]]
-; CHECK-NEXT:    br i1 [[TMP30]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP9:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP30]], label [[VEC_EPILOG_MIDDLE_BLOCK:%.*]], label [[VEC_EPILOG_VECTOR_BODY]], !llvm.loop [[LOOP11:![0-9]+]]
 ; CHECK:       vec.epilog.middle.block:
 ; CHECK-NEXT:    [[CMP_N6:%.*]] = icmp eq i64 10000, [[N_VEC3]]
 ; CHECK-NEXT:    br i1 [[CMP_N6]], label [[EXIT]], label [[VEC_EPILOG_SCALAR_PH]]
...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/150018


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