[llvm] [LAA] Fix WAW dependency analysis with negative distances (PR #155266)
Sebastian Pop via llvm-commits
llvm-commits at lists.llvm.org
Mon Aug 25 09:22:50 PDT 2025
https://github.com/sebpop created https://github.com/llvm/llvm-project/pull/155266
Previously, LAA would incorrectly classify Write-After-Write dependencies with negative distances as safe Forward dependencies, allowing inappropriate vectorization of loops with bidirectional WAW dependencies.
The issue occurred in loops like:
for(int i = 0; i < n; ++i) {
A[(i+1)*4] = 10; // First store
A[i] = 100; // Second store
}
The dependence distance from first store to second store is negative: {-16,+,-12}. However, this represents a bidirectional WAW dependency that DependenceAnalysis would report as 'output [<>]!', indicating dependency in both directions.
This patch fixes LAA to properly detect WAW dependencies with negative distances as unsafe, preventing incorrect vectorization.
The fix adds a check specifically for Write-After-Write dependencies before the general negative distance handling, ensuring they are classified as Unknown (unsafe) rather than Forward (safe).
A proper fix, not implemented here because it would be a major rework of LAA, is to implement bidirectional dependence checking that computes distances in both directions and detects inconsistent direction vectors.
>From a2aec677e2e3ec3177737a25f4068f23f3e9e998 Mon Sep 17 00:00:00 2001
From: Sebastian Pop <spop at nvidia.com>
Date: Sun, 24 Aug 2025 01:11:32 -0500
Subject: [PATCH] [LAA] Fix WAW dependency analysis with negative distances
Previously, LAA would incorrectly classify Write-After-Write dependencies
with negative distances as safe Forward dependencies, allowing inappropriate
vectorization of loops with bidirectional WAW dependencies.
The issue occurred in loops like:
for(int i = 0; i < n; ++i) {
A[(i+1)*4] = 10; // First store
A[i] = 100; // Second store
}
The dependence distance from first store to second store is negative:
{-16,+,-12}. However, this represents a bidirectional WAW dependency
that DependenceAnalysis would report as 'output [<>]!', indicating
dependency in both directions.
This patch fixes LAA to properly detect WAW dependencies with negative
distances as unsafe, preventing incorrect vectorization.
The fix adds a check specifically for Write-After-Write dependencies
before the general negative distance handling, ensuring they are
classified as Unknown (unsafe) rather than Forward (safe).
A proper fix, not implemented here because it would be a major rework of LAA,
is to implement bidirectional dependence checking that computes distances
in both directions and detects inconsistent direction vectors.
---
llvm/lib/Analysis/LoopAccessAnalysis.cpp | 15 +++
.../LoopAccessAnalysis/depend_diff_types.ll | 7 +-
.../forward-loop-carried.ll | 2 +-
.../forward-loop-independent.ll | 2 +-
.../waw-negative-dependence.ll | 109 ++++++++++++++++++
.../AArch64/sve-interleaved-accesses.ll | 75 ++++--------
.../LoopVectorize/interleaved-accesses.ll | 84 ++------------
7 files changed, 163 insertions(+), 131 deletions(-)
create mode 100644 llvm/test/Analysis/LoopAccessAnalysis/waw-negative-dependence.ll
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index bceddd0325276..e522d1392f7f9 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -2196,6 +2196,21 @@ MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
return Dependence::Unknown;
}
+ // For WAW (Write-After-Write) dependencies, negative distances in one
+ // direction can still represent unsafe dependencies. Since we only check
+ // dependencies in program order (AIdx < BIdx), a negative distance means
+ // the later write accesses memory locations before the earlier write.
+ // However, in a vectorized loop, both writes could execute simultaneously,
+ // potentially causing incorrect behavior. Therefore, WAW with negative
+ // distances should be treated as unsafe.
+ bool IsWriteAfterWrite = (AIsWrite && BIsWrite);
+ if (IsWriteAfterWrite) {
+ LLVM_DEBUG(
+ dbgs() << "LAA: WAW dependence with negative distance is unsafe\n");
+ return CheckCompletelyBeforeOrAfter() ? Dependence::NoDep
+ : Dependence::Unknown;
+ }
+
bool IsTrueDataDependence = (AIsWrite && !BIsWrite);
// Check if the first access writes to a location that is read in a later
// iteration, where the distance between them is not a multiple of a vector
diff --git a/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll b/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll
index 023a8c056968f..00a2ce7337d0d 100644
--- a/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll
+++ b/llvm/test/Analysis/LoopAccessAnalysis/depend_diff_types.ll
@@ -1,4 +1,4 @@
-; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 4
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
; RUN: opt -S -disable-output -passes='print<access-info>' < %s 2>&1 | FileCheck %s
@@ -449,9 +449,10 @@ exit:
define void @different_type_sizes_forward(ptr %dst) {
; CHECK-LABEL: 'different_type_sizes_forward'
; CHECK-NEXT: loop:
-; CHECK-NEXT: Memory dependences are safe
+; CHECK-NEXT: Report: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
+; CHECK-NEXT: Unknown data dependence.
; CHECK-NEXT: Dependences:
-; CHECK-NEXT: Forward:
+; CHECK-NEXT: Unknown:
; CHECK-NEXT: store i32 0, ptr %gep.10.iv, align 4 ->
; CHECK-NEXT: store i16 1, ptr %gep.iv, align 2
; CHECK-EMPTY:
diff --git a/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-carried.ll b/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-carried.ll
index adfd19923e921..8b00ff0ad2a59 100644
--- a/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-carried.ll
+++ b/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-carried.ll
@@ -70,7 +70,7 @@ define void @forward_different_access_sizes(ptr readnone %end, ptr %start) {
; CHECK-NEXT: store i32 0, ptr %gep.2, align 4 ->
; CHECK-NEXT: %l = load i24, ptr %gep.1, align 1
; CHECK-EMPTY:
-; CHECK-NEXT: Forward:
+; CHECK-NEXT: Unknown:
; CHECK-NEXT: store i32 0, ptr %gep.2, align 4 ->
; CHECK-NEXT: store i24 %l, ptr %ptr.iv, align 1
; CHECK-EMPTY:
diff --git a/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-independent.ll b/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-independent.ll
index 7fc9958dba552..218166526d7c0 100644
--- a/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-independent.ll
+++ b/llvm/test/Analysis/LoopAccessAnalysis/forward-loop-independent.ll
@@ -35,7 +35,7 @@ define void @f(ptr noalias %A, ptr noalias %B, ptr noalias %C, i64 %N) {
; CHECK-NEXT: store i32 %b_p2, ptr %Aidx_next, align 4 ->
; CHECK-NEXT: %a = load i32, ptr %Aidx, align 4
; CHECK-EMPTY:
-; CHECK-NEXT: Forward:
+; CHECK-NEXT: Unknown:
; CHECK-NEXT: store i32 %b_p2, ptr %Aidx_next, align 4 ->
; CHECK-NEXT: store i32 %b_p1, ptr %Aidx, align 4
; CHECK-EMPTY:
diff --git a/llvm/test/Analysis/LoopAccessAnalysis/waw-negative-dependence.ll b/llvm/test/Analysis/LoopAccessAnalysis/waw-negative-dependence.ll
new file mode 100644
index 0000000000000..be49af7d75460
--- /dev/null
+++ b/llvm/test/Analysis/LoopAccessAnalysis/waw-negative-dependence.ll
@@ -0,0 +1,109 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes='print<access-info>' -disable-output %s 2>&1 | FileCheck %s
+
+; Test that LAA correctly identifies Write-After-Write dependencies with negative
+; distances as unsafe. Previously, LAA would incorrectly classify negative distance
+; WAW dependencies as safe Forward dependencies, allowing inappropriate vectorization.
+;
+; This corresponds to the loop:
+; for(int i = 0; i < n; ++i) {
+; A[(i+1)*4] = 10; // First store: A[4, 8, 12, 16, ...]
+; A[i] = 100; // Second store: A[0, 1, 2, 3, 4, ...]
+; }
+;
+; The dependence distance from first store to second store is negative:
+; A[i] - A[(i+1)*4] = {0,+,4} - {16,+,16} = {-16,+,-12}
+; However, the dependence from second store to first store in the next iteration
+; would be positive: A[(i+1)*4] - A[i] = {16,+,16} - {0,+,4} = {16,+,12}
+;
+; This bidirectional dependence pattern (negative in one direction, positive in the
+; other) creates a Write-After-Write dependency that is unsafe for vectorization.
+; DependenceAnalysis would report this as "output [<>]!" indicating the complex
+; dependence direction. LAA must detect this as unsafe even when only checking
+; the negative distance direction.
+
+define void @test_waw_negative_dependence(i64 %n, ptr nocapture %A) {
+; CHECK-LABEL: 'test_waw_negative_dependence'
+; CHECK-NEXT: loop:
+; CHECK-NEXT: Report: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
+; CHECK-NEXT: Unknown data dependence.
+; CHECK-NEXT: Dependences:
+; CHECK-NEXT: Unknown:
+; CHECK-NEXT: store i32 10, ptr %arrayidx1, align 4 ->
+; CHECK-NEXT: store i32 100, ptr %arrayidx2, align 4
+; CHECK-EMPTY:
+; CHECK-NEXT: Run-time memory checks:
+; CHECK-NEXT: Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT: Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT: SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT: Expressions re-written:
+;
+entry:
+ %cmp8 = icmp sgt i64 %n, 0
+ br i1 %cmp8, label %loop, label %exit
+
+loop:
+ %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %loop ]
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+
+ ; First store: A[(i+1)*4] = 10
+ %0 = shl nsw i64 %indvars.iv.next, 2 ; (i+1)*4
+ %arrayidx1 = getelementptr inbounds i32, ptr %A, i64 %0
+ store i32 10, ptr %arrayidx1, align 4
+
+ ; Second store: A[i] = 100
+ %arrayidx2 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
+ store i32 100, ptr %arrayidx2, align 4
+
+ %exitcond.not = icmp eq i64 %indvars.iv.next, %n
+ br i1 %exitcond.not, label %exit, label %loop
+
+exit:
+ ret void
+}
+
+; Test a similar case but with different stride to ensure the fix is general.
+define void @test_waw_negative_dependence_different_stride(i64 %n, ptr nocapture %A) {
+; CHECK-LABEL: 'test_waw_negative_dependence_different_stride'
+; CHECK-NEXT: loop:
+; CHECK-NEXT: Report: unsafe dependent memory operations in loop. Use #pragma clang loop distribute(enable) to allow loop distribution to attempt to isolate the offending operations into a separate loop
+; CHECK-NEXT: Unknown data dependence.
+; CHECK-NEXT: Dependences:
+; CHECK-NEXT: Unknown:
+; CHECK-NEXT: store i32 10, ptr %arrayidx1, align 4 ->
+; CHECK-NEXT: store i32 100, ptr %arrayidx2, align 4
+; CHECK-EMPTY:
+; CHECK-NEXT: Run-time memory checks:
+; CHECK-NEXT: Grouped accesses:
+; CHECK-EMPTY:
+; CHECK-NEXT: Non vectorizable stores to invariant address were not found in loop.
+; CHECK-NEXT: SCEV assumptions:
+; CHECK-EMPTY:
+; CHECK-NEXT: Expressions re-written:
+;
+entry:
+ %cmp8 = icmp sgt i64 %n, 0
+ br i1 %cmp8, label %loop, label %exit
+
+loop:
+ %indvars.iv = phi i64 [ 0, %entry ], [ %indvars.iv.next, %loop ]
+ %indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
+
+ ; First store: A[(i+2)*2] = 10
+ %0 = add nsw i64 %indvars.iv, 2 ; i+2
+ %1 = shl nsw i64 %0, 1 ; (i+2)*2
+ %arrayidx1 = getelementptr inbounds i32, ptr %A, i64 %1
+ store i32 10, ptr %arrayidx1, align 4
+
+ ; Second store: A[i] = 100
+ %arrayidx2 = getelementptr inbounds i32, ptr %A, i64 %indvars.iv
+ store i32 100, ptr %arrayidx2, align 4
+
+ %exitcond.not = icmp eq i64 %indvars.iv.next, %n
+ br i1 %exitcond.not, label %exit, label %loop
+
+exit:
+ ret void
+}
diff --git a/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll b/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
index fd0bc0b6c20ef..e68744b8a6f37 100644
--- a/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
+++ b/llvm/test/Transforms/LoopVectorize/AArch64/sve-interleaved-accesses.ll
@@ -1158,53 +1158,22 @@ for.end:
define void @PR27626_5(ptr %a, i32 %x, i32 %y, i32 %z, i64 %n) #1 {
; CHECK-LABEL: @PR27626_5(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 5)
-; CHECK-NEXT: [[TMP0:%.*]] = add nsw i64 [[SMAX]], -4
-; CHECK-NEXT: [[TMP1:%.*]] = lshr i64 [[TMP0]], 1
-; CHECK-NEXT: [[TMP2:%.*]] = add nuw nsw i64 [[TMP1]], 1
-; CHECK-NEXT: [[TMP3:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT: [[TMP4:%.*]] = shl nuw nsw i64 [[TMP3]], 2
-; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp samesign ult i64 [[TMP2]], [[TMP4]]
-; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
-; CHECK: vector.ph:
-; CHECK-NEXT: [[TMP7:%.*]] = call i64 @llvm.vscale.i64()
-; CHECK-NEXT: [[TMP8:%.*]] = shl nuw nsw i64 [[TMP7]], 2
-; CHECK-NEXT: [[DOTNOT:%.*]] = sub nsw i64 0, [[TMP8]]
-; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[TMP2]], [[DOTNOT]]
-; CHECK-NEXT: [[TMP11:%.*]] = shl nuw i64 [[N_VEC]], 1
-; CHECK-NEXT: [[IND_END:%.*]] = or disjoint i64 [[TMP11]], 3
-; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[X:%.*]], i64 0
-; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <vscale x 4 x i32> [[BROADCAST_SPLATINSERT]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
-; CHECK-NEXT: [[BROADCAST_SPLATINSERT1:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[Y:%.*]], i64 0
-; CHECK-NEXT: [[BROADCAST_SPLAT2:%.*]] = shufflevector <vscale x 4 x i32> [[BROADCAST_SPLATINSERT1]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
-; CHECK-NEXT: [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <vscale x 4 x i32> poison, i32 [[Z:%.*]], i64 0
-; CHECK-NEXT: [[BROADCAST_SPLAT4:%.*]] = shufflevector <vscale x 4 x i32> [[BROADCAST_SPLATINSERT3]], <vscale x 4 x i32> poison, <vscale x 4 x i32> zeroinitializer
-; CHECK-NEXT: [[TMP10:%.*]] = call <vscale x 4 x i64> @llvm.stepvector.nxv4i64()
-; CHECK-NEXT: [[TMP21:%.*]] = shl <vscale x 4 x i64> [[TMP10]], splat (i64 1)
-; CHECK-NEXT: [[INDUCTION:%.*]] = add <vscale x 4 x i64> [[TMP21]], splat (i64 3)
-; CHECK-NEXT: [[TMP12:%.*]] = shl nuw nsw i64 [[TMP7]], 3
-; CHECK-NEXT: [[DOTSPLATINSERT:%.*]] = insertelement <vscale x 4 x i64> poison, i64 [[TMP12]], i64 0
-; CHECK-NEXT: [[DOTSPLAT:%.*]] = shufflevector <vscale x 4 x i64> [[DOTSPLATINSERT]], <vscale x 4 x i64> poison, <vscale x 4 x i32> zeroinitializer
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
-; CHECK: vector.body:
-; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NEXT: [[VEC_IND:%.*]] = phi <vscale x 4 x i64> [ [[INDUCTION]], [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NEXT: [[TMP13:%.*]] = add <vscale x 4 x i64> [[VEC_IND]], splat (i64 -1)
-; CHECK-NEXT: [[TMP14:%.*]] = add <vscale x 4 x i64> [[VEC_IND]], splat (i64 -3)
-; CHECK-NEXT: [[TMP15:%.*]] = getelementptr inbounds i32, ptr [[A:%.*]], <vscale x 4 x i64> [[VEC_IND]]
-; CHECK-NEXT: [[TMP16:%.*]] = getelementptr inbounds i32, ptr [[A]], <vscale x 4 x i64> [[TMP13]]
-; CHECK-NEXT: [[TMP17:%.*]] = getelementptr inbounds i32, ptr [[A]], <vscale x 4 x i64> [[TMP14]]
-; CHECK-NEXT: call void @llvm.masked.scatter.nxv4i32.nxv4p0(<vscale x 4 x i32> [[BROADCAST_SPLAT]], <vscale x 4 x ptr> [[TMP16]], i32 4, <vscale x 4 x i1> splat (i1 true))
-; CHECK-NEXT: call void @llvm.masked.scatter.nxv4i32.nxv4p0(<vscale x 4 x i32> [[BROADCAST_SPLAT2]], <vscale x 4 x ptr> [[TMP17]], i32 4, <vscale x 4 x i1> splat (i1 true))
-; CHECK-NEXT: call void @llvm.masked.scatter.nxv4i32.nxv4p0(<vscale x 4 x i32> [[BROADCAST_SPLAT4]], <vscale x 4 x ptr> [[TMP15]], i32 4, <vscale x 4 x i1> splat (i1 true))
-; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP8]]
-; CHECK-NEXT: [[VEC_IND_NEXT]] = add <vscale x 4 x i64> [[VEC_IND]], [[DOTSPLAT]]
-; CHECK-NEXT: [[TMP18:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP32:![0-9]+]]
-; CHECK: middle.block:
-; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[TMP2]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
-; CHECK: scalar.ph:
+; CHECK: for.body:
+; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[VECTOR_BODY]] ], [ 3, [[ENTRY:%.*]] ]
+; CHECK-NEXT: [[A_I:%.*]] = getelementptr inbounds nuw i32, ptr [[A:%.*]], i64 [[I]]
+; CHECK-NEXT: [[TMP0:%.*]] = getelementptr i32, ptr [[A]], i64 [[I]]
+; CHECK-NEXT: [[A_I_MINUS_1:%.*]] = getelementptr i8, ptr [[TMP0]], i64 -4
+; CHECK-NEXT: [[TMP1:%.*]] = getelementptr i32, ptr [[A]], i64 [[I]]
+; CHECK-NEXT: [[A_I_MINUS_3:%.*]] = getelementptr i8, ptr [[TMP1]], i64 -12
+; CHECK-NEXT: store i32 [[X:%.*]], ptr [[A_I_MINUS_1]], align 4
+; CHECK-NEXT: store i32 [[Y:%.*]], ptr [[A_I_MINUS_3]], align 4
+; CHECK-NEXT: store i32 [[Z:%.*]], ptr [[A_I]], align 4
+; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 2
+; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N:%.*]]
+; CHECK-NEXT: br i1 [[COND]], label [[VECTOR_BODY]], label [[FOR_END:%.*]]
+; CHECK: for.end:
+; CHECK-NEXT: ret void
;
entry:
br label %for.body
@@ -1281,21 +1250,21 @@ define void @PR34743(ptr %a, ptr %b, i64 %n) #1 {
; CHECK-NEXT: [[TMP18:%.*]] = add nuw nsw <vscale x 4 x i64> [[VEC_IND]], splat (i64 1)
; CHECK-NEXT: [[TMP19:%.*]] = add nuw nsw <vscale x 4 x i64> [[VEC_IND]], splat (i64 2)
; CHECK-NEXT: [[TMP20:%.*]] = getelementptr inbounds i16, ptr [[A]], <vscale x 4 x i64> [[TMP18]]
-; CHECK-NEXT: [[WIDE_MASKED_GATHER:%.*]] = call <vscale x 4 x i16> @llvm.masked.gather.nxv4i16.nxv4p0(<vscale x 4 x ptr> [[TMP20]], i32 4, <vscale x 4 x i1> splat (i1 true), <vscale x 4 x i16> poison), !alias.scope [[META34:![0-9]+]]
+; CHECK-NEXT: [[WIDE_MASKED_GATHER:%.*]] = call <vscale x 4 x i16> @llvm.masked.gather.nxv4i16.nxv4p0(<vscale x 4 x ptr> [[TMP20]], i32 4, <vscale x 4 x i1> splat (i1 true), <vscale x 4 x i16> poison), !alias.scope [[META32:![0-9]+]]
; CHECK-NEXT: [[TMP21:%.*]] = sext <vscale x 4 x i16> [[WIDE_MASKED_GATHER]] to <vscale x 4 x i32>
; CHECK-NEXT: [[TMP22:%.*]] = getelementptr inbounds i16, ptr [[A]], <vscale x 4 x i64> [[TMP19]]
-; CHECK-NEXT: [[WIDE_MASKED_GATHER4]] = call <vscale x 4 x i16> @llvm.masked.gather.nxv4i16.nxv4p0(<vscale x 4 x ptr> [[TMP22]], i32 4, <vscale x 4 x i1> splat (i1 true), <vscale x 4 x i16> poison), !alias.scope [[META34]]
+; CHECK-NEXT: [[WIDE_MASKED_GATHER4]] = call <vscale x 4 x i16> @llvm.masked.gather.nxv4i16.nxv4p0(<vscale x 4 x ptr> [[TMP22]], i32 4, <vscale x 4 x i1> splat (i1 true), <vscale x 4 x i16> poison), !alias.scope [[META32]]
; CHECK-NEXT: [[TMP23:%.*]] = call <vscale x 4 x i16> @llvm.vector.splice.nxv4i16(<vscale x 4 x i16> [[VECTOR_RECUR]], <vscale x 4 x i16> [[WIDE_MASKED_GATHER4]], i32 -1)
; CHECK-NEXT: [[TMP24:%.*]] = sext <vscale x 4 x i16> [[TMP23]] to <vscale x 4 x i32>
; CHECK-NEXT: [[TMP25:%.*]] = sext <vscale x 4 x i16> [[WIDE_MASKED_GATHER4]] to <vscale x 4 x i32>
; CHECK-NEXT: [[TMP26:%.*]] = mul nsw <vscale x 4 x i32> [[TMP24]], [[TMP21]]
; CHECK-NEXT: [[TMP27:%.*]] = mul nsw <vscale x 4 x i32> [[TMP26]], [[TMP25]]
; CHECK-NEXT: [[TMP28:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
-; CHECK-NEXT: store <vscale x 4 x i32> [[TMP27]], ptr [[TMP28]], align 4, !alias.scope [[META37:![0-9]+]], !noalias [[META34]]
+; CHECK-NEXT: store <vscale x 4 x i32> [[TMP27]], ptr [[TMP28]], align 4, !alias.scope [[META35:![0-9]+]], !noalias [[META32]]
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP10]]
; CHECK-NEXT: [[VEC_IND_NEXT]] = add <vscale x 4 x i64> [[VEC_IND]], [[DOTSPLAT]]
; CHECK-NEXT: [[TMP29:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[TMP29]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP39:![0-9]+]]
+; CHECK-NEXT: br i1 [[TMP29]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP37:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[TMP30:%.*]] = call i32 @llvm.vscale.i32()
; CHECK-NEXT: [[TMP31:%.*]] = shl nuw nsw i32 [[TMP30]], 2
@@ -1388,7 +1357,7 @@ define void @interleave_deinterleave_factor3(ptr writeonly noalias %dst, ptr rea
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
; CHECK-NEXT: [[VEC_IND_NEXT]] = add <vscale x 4 x i64> [[VEC_IND]], [[DOTSPLAT]]
; CHECK-NEXT: [[TMP18:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP41:![0-9]+]]
+; CHECK-NEXT: br i1 [[TMP18]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP39:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N_MOD_VF]], 0
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
@@ -1475,7 +1444,7 @@ define void @interleave_deinterleave(ptr writeonly noalias %dst, ptr readonly %a
; CHECK-NEXT: store <vscale x 16 x i32> [[INTERLEAVED_VEC13]], ptr [[TMP21]], align 4
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP3]]
; CHECK-NEXT: [[TMP25:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[TMP25]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP43:![0-9]+]]
+; CHECK-NEXT: br i1 [[TMP25]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP41:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[N_MOD_VF]], 0
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_COND_CLEANUP:%.*]], label [[SCALAR_PH]]
@@ -1584,7 +1553,7 @@ define void @interleave_deinterleave_reverse(ptr noalias nocapture readonly %A,
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], [[TMP1]]
; CHECK-NEXT: [[VEC_IND_NEXT]] = add <vscale x 4 x i32> [[VEC_IND]], [[DOTSPLAT]]
; CHECK-NEXT: [[TMP27:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1024
-; CHECK-NEXT: br i1 [[TMP27]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP45:![0-9]+]]
+; CHECK-NEXT: br i1 [[TMP27]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP43:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: br i1 true, label [[FOR_COND_CLEANUP:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
diff --git a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
index add58758788f9..aab21965d6877 100644
--- a/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
+++ b/llvm/test/Transforms/LoopVectorize/interleaved-accesses.ll
@@ -1348,82 +1348,20 @@ for.end:
define void @PR27626_5(ptr %a, i32 %x, i32 %y, i32 %z, i64 %n) {
; CHECK-LABEL: @PR27626_5(
; CHECK-NEXT: entry:
-; CHECK-NEXT: [[SMAX:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 5)
-; CHECK-NEXT: [[TMP0:%.*]] = add nsw i64 [[SMAX]], -4
-; CHECK-NEXT: [[TMP1:%.*]] = lshr i64 [[TMP0]], 1
-; CHECK-NEXT: [[TMP2:%.*]] = add nuw nsw i64 [[TMP1]], 1
-; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp slt i64 [[N]], 10
-; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
-; CHECK: vector.ph:
-; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[TMP2]], 9223372036854775804
-; CHECK-NEXT: [[TMP3:%.*]] = shl nuw i64 [[N_VEC]], 1
-; CHECK-NEXT: [[IND_END:%.*]] = or disjoint i64 [[TMP3]], 3
-; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
-; CHECK: vector.body:
-; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NEXT: [[VEC_IND:%.*]] = phi <4 x i64> [ <i64 3, i64 5, i64 7, i64 9>, [[VECTOR_PH]] ], [ [[VEC_IND_NEXT:%.*]], [[VECTOR_BODY]] ]
-; CHECK-NEXT: [[TMP4:%.*]] = shl i64 [[INDEX]], 1
-; CHECK-NEXT: [[TMP7:%.*]] = add <4 x i64> [[VEC_IND]], splat (i64 -1)
-; CHECK-NEXT: [[TMP8:%.*]] = add <4 x i64> [[VEC_IND]], splat (i64 -3)
-; CHECK-NEXT: [[TMP12:%.*]] = getelementptr i32, ptr [[A:%.*]], i64 [[TMP4]]
-; CHECK-NEXT: [[TMP9:%.*]] = getelementptr i8, ptr [[TMP12]], i64 12
-; CHECK-NEXT: [[TMP33:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP4]]
-; CHECK-NEXT: [[TMP10:%.*]] = getelementptr i8, ptr [[TMP33]], i64 20
-; CHECK-NEXT: [[TMP34:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP4]]
-; CHECK-NEXT: [[TMP11:%.*]] = getelementptr i8, ptr [[TMP34]], i64 28
-; CHECK-NEXT: [[TMP35:%.*]] = getelementptr i32, ptr [[A]], i64 [[TMP4]]
-; CHECK-NEXT: [[TMP13:%.*]] = getelementptr i8, ptr [[TMP35]], i64 36
-; CHECK-NEXT: [[TMP14:%.*]] = extractelement <4 x i64> [[TMP7]], i64 0
-; CHECK-NEXT: [[TMP15:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP14]]
-; CHECK-NEXT: [[TMP16:%.*]] = extractelement <4 x i64> [[TMP7]], i64 1
-; CHECK-NEXT: [[TMP17:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP16]]
-; CHECK-NEXT: [[TMP18:%.*]] = extractelement <4 x i64> [[TMP7]], i64 2
-; CHECK-NEXT: [[TMP19:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP18]]
-; CHECK-NEXT: [[TMP20:%.*]] = extractelement <4 x i64> [[TMP7]], i64 3
-; CHECK-NEXT: [[TMP21:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP20]]
-; CHECK-NEXT: [[TMP22:%.*]] = extractelement <4 x i64> [[TMP8]], i64 0
-; CHECK-NEXT: [[TMP23:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP22]]
-; CHECK-NEXT: [[TMP24:%.*]] = extractelement <4 x i64> [[TMP8]], i64 1
-; CHECK-NEXT: [[TMP25:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP24]]
-; CHECK-NEXT: [[TMP26:%.*]] = extractelement <4 x i64> [[TMP8]], i64 2
-; CHECK-NEXT: [[TMP27:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP26]]
-; CHECK-NEXT: [[TMP28:%.*]] = extractelement <4 x i64> [[TMP8]], i64 3
-; CHECK-NEXT: [[TMP29:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[TMP28]]
-; CHECK-NEXT: store i32 [[X:%.*]], ptr [[TMP15]], align 4
-; CHECK-NEXT: store i32 [[X]], ptr [[TMP17]], align 4
-; CHECK-NEXT: store i32 [[X]], ptr [[TMP19]], align 4
-; CHECK-NEXT: store i32 [[X]], ptr [[TMP21]], align 4
-; CHECK-NEXT: store i32 [[Y:%.*]], ptr [[TMP23]], align 4
-; CHECK-NEXT: store i32 [[Y]], ptr [[TMP25]], align 4
-; CHECK-NEXT: store i32 [[Y]], ptr [[TMP27]], align 4
-; CHECK-NEXT: store i32 [[Y]], ptr [[TMP29]], align 4
-; CHECK-NEXT: store i32 [[Z:%.*]], ptr [[TMP9]], align 4
-; CHECK-NEXT: store i32 [[Z]], ptr [[TMP10]], align 4
-; CHECK-NEXT: store i32 [[Z]], ptr [[TMP11]], align 4
-; CHECK-NEXT: store i32 [[Z]], ptr [[TMP13]], align 4
-; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
-; CHECK-NEXT: [[VEC_IND_NEXT]] = add <4 x i64> [[VEC_IND]], splat (i64 8)
-; CHECK-NEXT: [[TMP30:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[TMP30]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP34:![0-9]+]]
-; CHECK: middle.block:
-; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[TMP2]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
-; CHECK: scalar.ph:
-; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[IND_END]], [[MIDDLE_BLOCK]] ], [ 3, [[ENTRY:%.*]] ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
-; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[FOR_BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
-; CHECK-NEXT: [[A_I:%.*]] = getelementptr inbounds i32, ptr [[A]], i64 [[I]]
+; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[FOR_BODY]] ], [ 3, [[ENTRY:%.*]] ]
+; CHECK-NEXT: [[A_I:%.*]] = getelementptr inbounds nuw i32, ptr [[A:%.*]], i64 [[I]]
; CHECK-NEXT: [[TMP31:%.*]] = getelementptr i32, ptr [[A]], i64 [[I]]
; CHECK-NEXT: [[A_I_MINUS_1:%.*]] = getelementptr i8, ptr [[TMP31]], i64 -4
; CHECK-NEXT: [[TMP32:%.*]] = getelementptr i32, ptr [[A]], i64 [[I]]
; CHECK-NEXT: [[A_I_MINUS_3:%.*]] = getelementptr i8, ptr [[TMP32]], i64 -12
-; CHECK-NEXT: store i32 [[X]], ptr [[A_I_MINUS_1]], align 4
-; CHECK-NEXT: store i32 [[Y]], ptr [[A_I_MINUS_3]], align 4
-; CHECK-NEXT: store i32 [[Z]], ptr [[A_I]], align 4
+; CHECK-NEXT: store i32 [[X:%.*]], ptr [[A_I_MINUS_1]], align 4
+; CHECK-NEXT: store i32 [[Y:%.*]], ptr [[A_I_MINUS_3]], align 4
+; CHECK-NEXT: store i32 [[Z:%.*]], ptr [[A_I]], align 4
; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 2
-; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
-; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END]], !llvm.loop [[LOOP35:![0-9]+]]
+; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N:%.*]]
+; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END:%.*]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
@@ -1489,7 +1427,7 @@ define void @PR34743(ptr %a, ptr %b, i64 %n) {
; CHECK-NEXT: [[DOTIDX:%.*]] = shl i64 [[INDEX]], 2
; CHECK-NEXT: [[TMP17:%.*]] = getelementptr i8, ptr [[A]], i64 [[DOTIDX]]
; CHECK-NEXT: [[TMP7:%.*]] = getelementptr i8, ptr [[TMP17]], i64 2
-; CHECK-NEXT: [[WIDE_VEC:%.*]] = load <8 x i16>, ptr [[TMP7]], align 4
+; CHECK-NEXT: [[WIDE_VEC:%.*]] = load <8 x i16>, ptr [[TMP7]], align 4, !alias.scope [[META34:![0-9]+]]
; CHECK-NEXT: [[STRIDED_VEC:%.*]] = shufflevector <8 x i16> [[WIDE_VEC]], <8 x i16> poison, <4 x i32> <i32 0, i32 2, i32 4, i32 6>
; CHECK-NEXT: [[STRIDED_VEC4]] = shufflevector <8 x i16> [[WIDE_VEC]], <8 x i16> poison, <4 x i32> <i32 1, i32 3, i32 5, i32 7>
; CHECK-NEXT: [[TMP8:%.*]] = shufflevector <4 x i16> [[VECTOR_RECUR]], <4 x i16> [[STRIDED_VEC4]], <4 x i32> <i32 3, i32 4, i32 5, i32 6>
@@ -1499,10 +1437,10 @@ define void @PR34743(ptr %a, ptr %b, i64 %n) {
; CHECK-NEXT: [[TMP12:%.*]] = mul nsw <4 x i32> [[TMP9]], [[TMP10]]
; CHECK-NEXT: [[TMP13:%.*]] = mul nsw <4 x i32> [[TMP12]], [[TMP11]]
; CHECK-NEXT: [[TMP14:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
-; CHECK-NEXT: store <4 x i32> [[TMP13]], ptr [[TMP14]], align 4, !alias.scope [[META36:![0-9]+]], !noalias [[META39:![0-9]+]]
+; CHECK-NEXT: store <4 x i32> [[TMP13]], ptr [[TMP14]], align 4, !alias.scope [[META37:![0-9]+]], !noalias [[META34]]
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT: [[TMP15:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
-; CHECK-NEXT: br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP41:![0-9]+]]
+; CHECK-NEXT: br i1 [[TMP15]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP39:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[VECTOR_RECUR_EXTRACT:%.*]] = extractelement <8 x i16> [[WIDE_VEC]], i64 7
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[TMP1]], [[N_VEC]]
@@ -1531,7 +1469,7 @@ define void @PR34743(ptr %a, ptr %b, i64 %n) {
; CHECK-NEXT: [[ARRAYIDX5:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[I]]
; CHECK-NEXT: store i32 [[MUL012]], ptr [[ARRAYIDX5]], align 4
; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i64 [[IV]], [[N]]
-; CHECK-NEXT: br i1 [[EXITCOND]], label [[END]], label [[LOOP]], !llvm.loop [[LOOP42:![0-9]+]]
+; CHECK-NEXT: br i1 [[EXITCOND]], label [[END]], label [[LOOP]], !llvm.loop [[LOOP40:![0-9]+]]
; CHECK: end:
; CHECK-NEXT: ret void
;
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