[llvm] [LV] Avoid redundant SCEVChecks on active lane mask (PR #171605)

via llvm-commits llvm-commits at lists.llvm.org
Wed Dec 10 04:19:25 PST 2025


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-llvm-transforms

Author: Ramkumar Ramachandra (artagnon)

<details>
<summary>Changes</summary>

When using an active lane mask, all SCEVChecks except those for stride-versioning are redundant.

---

Patch is 35.71 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/171605.diff


5 Files Affected:

- (modified) llvm/lib/Transforms/Vectorize/LoopVectorize.cpp (+6-3) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/conditional-branches-cost.ll (+37-60) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll (+4-64) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/low_trip_count_predicates.ll (+7-31) 
- (modified) llvm/test/Transforms/LoopVectorize/AArch64/predicated-costs.ll (+18-43) 


``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 15d0fa41bd902..96a567307063b 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1819,7 +1819,8 @@ class GeneratedRTChecks {
   /// there is no vector code generation, the check blocks are removed
   /// completely.
   void create(Loop *L, const LoopAccessInfo &LAI,
-              const SCEVPredicate &UnionPred, ElementCount VF, unsigned IC) {
+              const SCEVPredicate &UnionPred, ElementCount VF, unsigned IC,
+              bool UseActiveLaneMask) {
 
     // Hard cutoff to limit compile-time increase in case a very large number of
     // runtime checks needs to be generated.
@@ -1837,7 +1838,8 @@ class GeneratedRTChecks {
     // ensure the blocks are properly added to LoopInfo & DominatorTree. Those
     // may be used by SCEVExpander. The blocks will be un-linked from their
     // predecessors and removed from LI & DT at the end of the function.
-    if (!UnionPred.isAlwaysTrue()) {
+    if (!UnionPred.isAlwaysTrue() &&
+        (!UseActiveLaneMask || !LAI.getSymbolicStrides().empty())) {
       SCEVCheckBlock = SplitBlock(Preheader, Preheader->getTerminator(), DT, LI,
                                   nullptr, "vector.scevcheck");
 
@@ -10094,7 +10096,8 @@ bool LoopVectorizePass::processLoop(Loop *L) {
     //  Optimistically generate runtime checks if they are needed. Drop them if
     //  they turn out to not be profitable.
     if (VF.Width.isVector() || SelectedIC > 1) {
-      Checks.create(L, *LVL.getLAI(), PSE.getPredicate(), VF.Width, SelectedIC);
+      Checks.create(L, *LVL.getLAI(), PSE.getPredicate(), VF.Width, SelectedIC,
+                    useActiveLaneMask(CM.getTailFoldingStyle()));
 
       // Bail out early if either the SCEV or memory runtime checks are known to
       // fail. In that case, the vector loop would never execute.
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/conditional-branches-cost.ll b/llvm/test/Transforms/LoopVectorize/AArch64/conditional-branches-cost.ll
index b549a06f08f8c..d695dc51907f5 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/conditional-branches-cost.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/conditional-branches-cost.ll
@@ -840,31 +840,7 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-SAME: ptr noalias [[SRC_1:%.*]], ptr noalias [[SRC_2:%.*]], ptr noalias [[SRC_3:%.*]], ptr noalias [[SRC_4:%.*]], ptr noalias [[DST:%.*]], i64 [[N:%.*]]) #[[ATTR3:[0-9]+]] {
 ; PRED-NEXT:  [[ENTRY:.*:]]
 ; PRED-NEXT:    [[TMP0:%.*]] = add i64 [[N]], 1
-; PRED-NEXT:    br label %[[VECTOR_SCEVCHECK:.*]]
-; PRED:       [[VECTOR_SCEVCHECK]]:
-; PRED-NEXT:    [[MUL:%.*]] = call { i64, i1 } @llvm.umul.with.overflow.i64(i64 16, i64 [[N]])
-; PRED-NEXT:    [[MUL_RESULT:%.*]] = extractvalue { i64, i1 } [[MUL]], 0
-; PRED-NEXT:    [[MUL_OVERFLOW:%.*]] = extractvalue { i64, i1 } [[MUL]], 1
-; PRED-NEXT:    [[TMP2:%.*]] = getelementptr i8, ptr [[DST]], i64 [[MUL_RESULT]]
-; PRED-NEXT:    [[TMP3:%.*]] = icmp ult ptr [[TMP2]], [[DST]]
-; PRED-NEXT:    [[TMP4:%.*]] = or i1 [[TMP3]], [[MUL_OVERFLOW]]
-; PRED-NEXT:    [[SCEVGEP:%.*]] = getelementptr i8, ptr [[DST]], i64 4
-; PRED-NEXT:    [[MUL1:%.*]] = call { i64, i1 } @llvm.umul.with.overflow.i64(i64 16, i64 [[N]])
-; PRED-NEXT:    [[MUL_RESULT2:%.*]] = extractvalue { i64, i1 } [[MUL1]], 0
-; PRED-NEXT:    [[MUL_OVERFLOW3:%.*]] = extractvalue { i64, i1 } [[MUL1]], 1
-; PRED-NEXT:    [[TMP6:%.*]] = getelementptr i8, ptr [[SCEVGEP]], i64 [[MUL_RESULT2]]
-; PRED-NEXT:    [[TMP7:%.*]] = icmp ult ptr [[TMP6]], [[SCEVGEP]]
-; PRED-NEXT:    [[TMP8:%.*]] = or i1 [[TMP7]], [[MUL_OVERFLOW3]]
-; PRED-NEXT:    [[SCEVGEP4:%.*]] = getelementptr i8, ptr [[DST]], i64 8
-; PRED-NEXT:    [[MUL5:%.*]] = call { i64, i1 } @llvm.umul.with.overflow.i64(i64 16, i64 [[N]])
-; PRED-NEXT:    [[MUL_RESULT6:%.*]] = extractvalue { i64, i1 } [[MUL5]], 0
-; PRED-NEXT:    [[MUL_OVERFLOW7:%.*]] = extractvalue { i64, i1 } [[MUL5]], 1
-; PRED-NEXT:    [[TMP10:%.*]] = getelementptr i8, ptr [[SCEVGEP4]], i64 [[MUL_RESULT6]]
-; PRED-NEXT:    [[TMP11:%.*]] = icmp ult ptr [[TMP10]], [[SCEVGEP4]]
-; PRED-NEXT:    [[TMP12:%.*]] = or i1 [[TMP11]], [[MUL_OVERFLOW7]]
-; PRED-NEXT:    [[TMP13:%.*]] = or i1 [[TMP4]], [[TMP8]]
-; PRED-NEXT:    [[TMP14:%.*]] = or i1 [[TMP13]], [[TMP12]]
-; PRED-NEXT:    br i1 [[TMP14]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; PRED-NEXT:    br label %[[VECTOR_PH:.*]]
 ; PRED:       [[VECTOR_PH]]:
 ; PRED-NEXT:    [[TMP15:%.*]] = sub i64 [[TMP0]], 8
 ; PRED-NEXT:    [[TMP16:%.*]] = icmp ugt i64 [[TMP0]], 8
@@ -872,9 +848,9 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    [[ACTIVE_LANE_MASK_ENTRY:%.*]] = call <8 x i1> @llvm.get.active.lane.mask.v8i1.i64(i64 0, i64 [[TMP0]])
 ; PRED-NEXT:    br label %[[VECTOR_BODY:.*]]
 ; PRED:       [[VECTOR_BODY]]:
-; PRED-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE27:.*]] ]
-; PRED-NEXT:    [[ACTIVE_LANE_MASK:%.*]] = phi <8 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[PRED_STORE_CONTINUE27]] ]
-; PRED-NEXT:    [[VEC_IND:%.*]] = phi <8 x i64> [ <i64 0, i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE27]] ]
+; PRED-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_STORE_CONTINUE20:.*]] ]
+; PRED-NEXT:    [[ACTIVE_LANE_MASK:%.*]] = phi <8 x i1> [ [[ACTIVE_LANE_MASK_ENTRY]], %[[VECTOR_PH]] ], [ [[ACTIVE_LANE_MASK_NEXT:%.*]], %[[PRED_STORE_CONTINUE20]] ]
+; PRED-NEXT:    [[VEC_IND:%.*]] = phi <8 x i64> [ <i64 0, i64 1, i64 2, i64 3, i64 4, i64 5, i64 6, i64 7>, %[[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], %[[PRED_STORE_CONTINUE20]] ]
 ; PRED-NEXT:    [[TMP18:%.*]] = load float, ptr [[SRC_1]], align 4
 ; PRED-NEXT:    [[BROADCAST_SPLATINSERT8:%.*]] = insertelement <8 x float> poison, float [[TMP18]], i64 0
 ; PRED-NEXT:    [[BROADCAST_SPLAT9:%.*]] = shufflevector <8 x float> [[BROADCAST_SPLATINSERT8]], <8 x float> poison, <8 x i32> zeroinitializer
@@ -909,8 +885,8 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE]]
 ; PRED:       [[PRED_STORE_CONTINUE]]:
 ; PRED-NEXT:    [[TMP35:%.*]] = extractelement <8 x i1> [[TMP26]], i32 1
-; PRED-NEXT:    br i1 [[TMP35]], label %[[PRED_STORE_IF14:.*]], label %[[PRED_STORE_CONTINUE15:.*]]
-; PRED:       [[PRED_STORE_IF14]]:
+; PRED-NEXT:    br i1 [[TMP35]], label %[[PRED_STORE_IF7:.*]], label %[[PRED_STORE_CONTINUE8:.*]]
+; PRED:       [[PRED_STORE_IF7]]:
 ; PRED-NEXT:    [[TMP36:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 1
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP36]], align 4
 ; PRED-NEXT:    [[TMP37:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 1
@@ -921,11 +897,11 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP40]], align 4
 ; PRED-NEXT:    [[TMP41:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 1
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP41]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE15]]
-; PRED:       [[PRED_STORE_CONTINUE15]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE8]]
+; PRED:       [[PRED_STORE_CONTINUE8]]:
 ; PRED-NEXT:    [[TMP42:%.*]] = extractelement <8 x i1> [[TMP26]], i32 2
-; PRED-NEXT:    br i1 [[TMP42]], label %[[PRED_STORE_IF16:.*]], label %[[PRED_STORE_CONTINUE17:.*]]
-; PRED:       [[PRED_STORE_IF16]]:
+; PRED-NEXT:    br i1 [[TMP42]], label %[[PRED_STORE_IF9:.*]], label %[[PRED_STORE_CONTINUE10:.*]]
+; PRED:       [[PRED_STORE_IF9]]:
 ; PRED-NEXT:    [[TMP43:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 2
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP43]], align 4
 ; PRED-NEXT:    [[TMP44:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 2
@@ -936,11 +912,11 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP47]], align 4
 ; PRED-NEXT:    [[TMP48:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 2
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP48]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE17]]
-; PRED:       [[PRED_STORE_CONTINUE17]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE10]]
+; PRED:       [[PRED_STORE_CONTINUE10]]:
 ; PRED-NEXT:    [[TMP49:%.*]] = extractelement <8 x i1> [[TMP26]], i32 3
-; PRED-NEXT:    br i1 [[TMP49]], label %[[PRED_STORE_IF18:.*]], label %[[PRED_STORE_CONTINUE19:.*]]
-; PRED:       [[PRED_STORE_IF18]]:
+; PRED-NEXT:    br i1 [[TMP49]], label %[[PRED_STORE_IF11:.*]], label %[[PRED_STORE_CONTINUE12:.*]]
+; PRED:       [[PRED_STORE_IF11]]:
 ; PRED-NEXT:    [[TMP50:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 3
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP50]], align 4
 ; PRED-NEXT:    [[TMP51:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 3
@@ -951,11 +927,11 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP54]], align 4
 ; PRED-NEXT:    [[TMP55:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 3
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP55]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE19]]
-; PRED:       [[PRED_STORE_CONTINUE19]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE12]]
+; PRED:       [[PRED_STORE_CONTINUE12]]:
 ; PRED-NEXT:    [[TMP56:%.*]] = extractelement <8 x i1> [[TMP26]], i32 4
-; PRED-NEXT:    br i1 [[TMP56]], label %[[PRED_STORE_IF20:.*]], label %[[PRED_STORE_CONTINUE21:.*]]
-; PRED:       [[PRED_STORE_IF20]]:
+; PRED-NEXT:    br i1 [[TMP56]], label %[[PRED_STORE_IF13:.*]], label %[[PRED_STORE_CONTINUE14:.*]]
+; PRED:       [[PRED_STORE_IF13]]:
 ; PRED-NEXT:    [[TMP57:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 4
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP57]], align 4
 ; PRED-NEXT:    [[TMP58:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 4
@@ -966,11 +942,11 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP61]], align 4
 ; PRED-NEXT:    [[TMP62:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 4
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP62]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE21]]
-; PRED:       [[PRED_STORE_CONTINUE21]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE14]]
+; PRED:       [[PRED_STORE_CONTINUE14]]:
 ; PRED-NEXT:    [[TMP63:%.*]] = extractelement <8 x i1> [[TMP26]], i32 5
-; PRED-NEXT:    br i1 [[TMP63]], label %[[PRED_STORE_IF22:.*]], label %[[PRED_STORE_CONTINUE23:.*]]
-; PRED:       [[PRED_STORE_IF22]]:
+; PRED-NEXT:    br i1 [[TMP63]], label %[[PRED_STORE_IF15:.*]], label %[[PRED_STORE_CONTINUE16:.*]]
+; PRED:       [[PRED_STORE_IF15]]:
 ; PRED-NEXT:    [[TMP64:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 5
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP64]], align 4
 ; PRED-NEXT:    [[TMP65:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 5
@@ -981,11 +957,11 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP68]], align 4
 ; PRED-NEXT:    [[TMP69:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 5
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP69]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE23]]
-; PRED:       [[PRED_STORE_CONTINUE23]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE16]]
+; PRED:       [[PRED_STORE_CONTINUE16]]:
 ; PRED-NEXT:    [[TMP70:%.*]] = extractelement <8 x i1> [[TMP26]], i32 6
-; PRED-NEXT:    br i1 [[TMP70]], label %[[PRED_STORE_IF24:.*]], label %[[PRED_STORE_CONTINUE25:.*]]
-; PRED:       [[PRED_STORE_IF24]]:
+; PRED-NEXT:    br i1 [[TMP70]], label %[[PRED_STORE_IF17:.*]], label %[[PRED_STORE_CONTINUE18:.*]]
+; PRED:       [[PRED_STORE_IF17]]:
 ; PRED-NEXT:    [[TMP71:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 6
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP71]], align 4
 ; PRED-NEXT:    [[TMP72:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 6
@@ -996,11 +972,11 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP75]], align 4
 ; PRED-NEXT:    [[TMP76:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 6
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP76]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE25]]
-; PRED:       [[PRED_STORE_CONTINUE25]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE18]]
+; PRED:       [[PRED_STORE_CONTINUE18]]:
 ; PRED-NEXT:    [[TMP77:%.*]] = extractelement <8 x i1> [[TMP26]], i32 7
-; PRED-NEXT:    br i1 [[TMP77]], label %[[PRED_STORE_IF26:.*]], label %[[PRED_STORE_CONTINUE27]]
-; PRED:       [[PRED_STORE_IF26]]:
+; PRED-NEXT:    br i1 [[TMP77]], label %[[PRED_STORE_IF19:.*]], label %[[PRED_STORE_CONTINUE20]]
+; PRED:       [[PRED_STORE_IF19]]:
 ; PRED-NEXT:    [[TMP78:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 7
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP78]], align 4
 ; PRED-NEXT:    [[TMP79:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 7
@@ -1011,8 +987,8 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP82]], align 4
 ; PRED-NEXT:    [[TMP83:%.*]] = extractelement <8 x ptr> [[TMP27]], i32 7
 ; PRED-NEXT:    store float 0.000000e+00, ptr [[TMP83]], align 4
-; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE27]]
-; PRED:       [[PRED_STORE_CONTINUE27]]:
+; PRED-NEXT:    br label %[[PRED_STORE_CONTINUE20]]
+; PRED:       [[PRED_STORE_CONTINUE20]]:
 ; PRED-NEXT:    [[INDEX_NEXT]] = add i64 [[INDEX]], 8
 ; PRED-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <8 x i1> @llvm.get.active.lane.mask.v8i1.i64(i64 [[INDEX]], i64 [[TMP17]])
 ; PRED-NEXT:    [[TMP84:%.*]] = extractelement <8 x i1> [[ACTIVE_LANE_MASK_NEXT]], i32 0
@@ -1020,8 +996,9 @@ define void @test_conditional_interleave_group (ptr noalias %src.1, ptr noalias
 ; PRED-NEXT:    [[VEC_IND_NEXT]] = add <8 x i64> [[VEC_IND]], splat (i64 8)
 ; PRED-NEXT:    br i1 [[TMP85]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
 ; PRED:       [[MIDDLE_BLOCK]]:
-; PRED-NEXT:    br [[EXIT:label %.*]]
-; PRED:       [[SCALAR_PH]]:
+; PRED-NEXT:    br label %[[EXIT:.*]]
+; PRED:       [[EXIT]]:
+; PRED-NEXT:    ret void
 ;
 entry:
   br label %loop.header
@@ -1124,7 +1101,7 @@ define void @redundant_branch_and_tail_folding(ptr %dst, i1 %c) {
 ; PRED-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
 ; PRED-NEXT:    [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 4)
 ; PRED-NEXT:    [[TMP11:%.*]] = icmp eq i64 [[INDEX_NEXT]], 24
-; PRED-NEXT:    br i1 [[TMP11]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; PRED-NEXT:    br i1 [[TMP11]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
 ; PRED:       [[MIDDLE_BLOCK]]:
 ; PRED-NEXT:    br label %[[EXIT:.*]]
 ; PRED:       [[EXIT]]:
@@ -1313,7 +1290,7 @@ define void @pred_udiv_select_cost(ptr %A, ptr %B, ptr %C, i64 %n, i8 %y) #1 {
 ; PRED-NEXT:    [[ACTIVE_LANE_MASK_NEXT]] = call <vscale x 16 x i1> @llvm.get.active.lane.mask.nxv16i1.i64(i64 [[INDEX]], i64 [[TMP11]])
 ; PRED-NEXT:    [[TMP28:%.*]] = extractelement <vscale x 16 x i1> [[ACTIVE_LANE_MASK_NEXT]], i32 0
 ; PRED-NEXT:    [[TMP29:%.*]] = xor i1 [[TMP28]], true
-; PRED-NEXT:    br i1 [[TMP29]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP7:![0-9]+]]
+; PRED-NEXT:    br i1 [[TMP29]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
 ; PRED:       [[MIDDLE_BLOCK]]:
 ; PRED-NEXT:    br [[EXIT:label %.*]]
 ; PRED:       [[SCALAR_PH]]:
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
index 72e813b62025f..23612191c7b9a 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/divs-with-scalable-vfs.ll
@@ -97,14 +97,7 @@ define void @sdiv_feeding_gep_predicated(ptr %dst, i32 %x, i64 %M, i64 %conv6, i
 ; CHECK-SAME: ptr [[DST:%.*]], i32 [[X:%.*]], i64 [[M:%.*]], i64 [[CONV6:%.*]], i64 [[N:%.*]]) #[[ATTR0]] {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
 ; CHECK-NEXT:    [[CONV61:%.*]] = zext i32 [[X]] to i64
-; CHECK-NEXT:    br label %[[VECTOR_SCEVCHECK:.*]]
-; CHECK:       [[VECTOR_SCEVCHECK]]:
-; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[N]], -1
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[TMP0]] to i32
-; CHECK-NEXT:    [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 0
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp ugt i64 [[TMP0]], 4294967295
-; CHECK-NEXT:    [[TMP4:%.*]] = or i1 [[TMP2]], [[TMP3]]
-; CHECK-NEXT:    br i1 [[TMP4]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
 ; CHECK:       [[VECTOR_PH]]:
 ; CHECK-NEXT:    [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP6:%.*]] = mul nuw i64 [[TMP5]], 2
@@ -148,28 +141,6 @@ define void @sdiv_feeding_gep_predicated(ptr %dst, i32 %x, i64 %M, i64 %conv6, i
 ; CHECK-NEXT:    br i1 [[TMP36]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP4:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
 ; CHECK-NEXT:    br label %[[EXIT:.*]]
-; CHECK:       [[SCALAR_PH]]:
-; CHECK-NEXT:    br label %[[LOOP:.*]]
-; CHECK:       [[LOOP]]:
-; CHECK-NEXT:    [[IV:%.*]] = phi i64 [ 0, %[[SCALAR_PH]] ], [ [[IV_NEXT:%.*]], %[[LOOP_LATCH:.*]] ]
-; CHECK-NEXT:    [[C:%.*]] = icmp ule i64 [[IV]], [[M]]
-; CHECK-NEXT:    br i1 [[C]], label %[[THEN:.*]], label %[[LOOP_LATCH]]
-; CHECK:       [[THEN]]:
-; CHECK-NEXT:    [[DIV18:%.*]] = sdiv i64 [[M]], [[CONV6]]
-; CHECK-NEXT:    [[CONV20:%.*]] = trunc i64 [[DIV18]] to i32
-; CHECK-NEXT:    [[MUL30:%.*]] = mul i64 [[DIV18]], [[CONV61]]
-; CHECK-NEXT:    [[SUB31:%.*]] = sub i64 [[IV]], [[MUL30]]
-; CHECK-NEXT:    [[CONV34:%.*]] = trunc i64 [[SUB31]] to i32
-; CHECK-NEXT:    [[MUL35:%.*]] = mul i32 [[X]], [[CONV20]]
-; CHECK-NEXT:    [[ADD36:%.*]] = add i32 [[MUL35]], [[CONV34]]
-; CHECK-NEXT:    [[IDXPROM:%.*]] = sext i32 [[ADD36]] to i64
-; CHECK-NEXT:    [[GEP:%.*]] = getelementptr double, ptr [[DST]], i64 [[IDXPROM]]
-; CHECK-NEXT:    store double 0.000000e+00, ptr [[GEP]], align 8
-; CHECK-NEXT:    br label %[[LOOP_LATCH]]
-; CHECK:       [[LOOP_LATCH]]:
-; CHECK-NEXT:    [[IV_NEXT]] = add i64 [[IV]], 1
-; CHECK-NEXT:    [[EC:%.*]] = icmp eq i64 [[IV_NEXT]], [[N]]
-; CHECK-NEXT:    br i1 [[EC]], label %[[EXIT]], label %[[LOOP]], !llvm.loop [[LOOP5:![0-9]+]]
 ; CHECK:       [[EXIT]]:
 ; CHECK-NEXT:    ret void
 ;
@@ -212,13 +183,7 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; CHECK-NEXT:    [[MUL_1_I:%.*]] = mul i64 [[X]], [[X]]
 ; CHECK-NEXT:    [[MUL_2_I:%.*]] = mul i64 [[MUL_1_I]], [[X]]
 ; CHECK-NEXT:    [[TMP0:%.*]] = add i64 [[N]], 1
-; CHECK-NEXT:    br label %[[VECTOR_SCEVCHECK:.*]]
-; CHECK:       [[VECTOR_SCEVCHECK]]:
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[N]] to i32
-; CHECK-NEXT:    [[TMP2:%.*]] = icmp slt i32 [[TMP1]], 0
-; CHECK-NEXT:    [[TMP3:%.*]] = icmp ugt i64 [[N]], 4294967295
-; CHECK-NEXT:    [[TMP4:%.*]] = or i1 [[TMP2]], [[TMP3]]
-; CHECK-NEXT:    br i1 [[TMP4]], label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
+; CHECK-NEXT:    br label %[[VECTOR_PH:.*]]
 ; CHECK:       [[VECTOR_PH]]:
 ; CHECK-NEXT:    [[TMP5:%.*]] = call i64 @llvm.vscale.i64()
 ; CHECK-NEXT:    [[TMP6:%.*]] = mul nuw i64 [[TMP5]], 2
@@ -262,32 +227,9 @@ define void @udiv_urem_feeding_gep(i64 %x, ptr %dst, i64 %N) {
 ; CHECK-NEXT:    [[TMP39:%.*]] = extractelement <vscale x 2 x i1> [[ACTIVE_LANE_MASK_NEXT]], i32 0
 ; CHECK-NEXT:    [[TMP40:%.*]] = xor i1 [[TMP39]], true
 ; CHECK-NEXT:    [[VEC_IND_NEXT]] = add <vscale x 2 x i64> [[VEC_IND]], [[BROADCAST_SPLAT4]]
-; CHECK-NEXT:    br i1 [[TMP40]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP6:![0-9]+]]
+; CHECK-NEXT:    br i1 [[TMP40]], label %[[MIDDLE_BLOCK:.*]], label %[[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
 ; CHECK:       [[MIDDLE_BLOCK]]:
 ; CHECK-NEXT:    br label %[[EXIT:.*]]
-; CHECK:       [[SCALAR_PH]]:
-...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/171605


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