[llvm] [SLP]Do not consider non-profitable loads slices (PR #149209)
via llvm-commits
llvm-commits at lists.llvm.org
Wed Jul 16 15:45:58 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Alexey Bataev (alexey-bataev)
<details>
<summary>Changes</summary>
If all slices are small and end up with strided or even vectorization
states, better to not consider these candidates for the vectorization
and try to vectorize the whole bunch as gathered loads.
---
Full diff: https://github.com/llvm/llvm-project/pull/149209.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+6)
- (modified) llvm/test/Transforms/SLPVectorizer/X86/matched-nodes-updated.ll (+19-25)
``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index da6af353c709f..9446e16532115 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -11693,6 +11693,7 @@ void BoUpSLP::transformNodes() {
if (StartIdx + VF > End)
continue;
SmallVector<std::pair<unsigned, unsigned>> Slices;
+ bool AllStrided = true;
for (unsigned Cnt = StartIdx; Cnt + VF <= End; Cnt += VF) {
ArrayRef<Value *> Slice = VL.slice(Cnt, VF);
// If any instruction is vectorized already - do not try again.
@@ -11743,6 +11744,9 @@ void BoUpSLP::transformNodes() {
SmallVector<Value *> PointerOps;
LoadsState Res =
canVectorizeLoads(Slice, Slice.front(), Order, PointerOps);
+ AllStrided &= Res == LoadsState::StridedVectorize ||
+ Res == LoadsState::ScatterVectorize ||
+ Res == LoadsState::Gather;
// Do not vectorize gathers.
if (Res == LoadsState::ScatterVectorize ||
Res == LoadsState::Gather) {
@@ -11772,6 +11776,8 @@ void BoUpSLP::transformNodes() {
}
Slices.emplace_back(Cnt, Slice.size());
}
+ if (VF == 2 && AllStrided && Slices.size() > 2)
+ continue;
auto AddCombinedNode = [&](unsigned Idx, unsigned Cnt, unsigned Sz) {
E.CombinedEntriesWithIndices.emplace_back(Idx, Cnt);
if (StartIdx == Cnt)
diff --git a/llvm/test/Transforms/SLPVectorizer/X86/matched-nodes-updated.ll b/llvm/test/Transforms/SLPVectorizer/X86/matched-nodes-updated.ll
index f56af934f19f5..b1864b43512d8 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/matched-nodes-updated.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/matched-nodes-updated.ll
@@ -14,50 +14,44 @@ define i32 @test(i32 %s.0) {
; CHECK: [[IF_END3:.*]]:
; CHECK-NEXT: br label %[[IF_END6:.*]]
; CHECK: [[IF_END6]]:
-; CHECK-NEXT: [[J_4:%.*]] = phi i32 [ 0, %[[IF_END3]] ], [ [[TMP28:%.*]], %[[O]] ]
-; CHECK-NEXT: [[TMP2:%.*]] = phi <2 x i32> [ poison, %[[IF_END3]] ], [ zeroinitializer, %[[O]] ]
-; CHECK-NEXT: [[TMP3:%.*]] = phi <2 x i32> [ poison, %[[IF_END3]] ], [ zeroinitializer, %[[O]] ]
-; CHECK-NEXT: [[TMP4:%.*]] = phi <2 x i32> [ poison, %[[IF_END3]] ], [ [[TMP22:%.*]], %[[O]] ]
+; CHECK-NEXT: [[TMP2:%.*]] = phi <2 x i32> [ poison, %[[IF_END3]] ], [ [[TMP24:%.*]], %[[O]] ]
+; CHECK-NEXT: [[TMP3:%.*]] = phi <4 x i32> [ poison, %[[IF_END3]] ], [ zeroinitializer, %[[O]] ]
+; CHECK-NEXT: [[TMP4:%.*]] = phi <2 x i32> [ poison, %[[IF_END3]] ], [ [[TMP29:%.*]], %[[O]] ]
; CHECK-NEXT: [[TMP5:%.*]] = xor <2 x i32> [[TMP4]], zeroinitializer
-; CHECK-NEXT: [[TMP6:%.*]] = shufflevector <2 x i32> [[TMP22]], <2 x i32> poison, <8 x i32> <i32 poison, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP7:%.*]] = shufflevector <2 x i32> [[TMP22]], <2 x i32> poison, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP8:%.*]] = shufflevector <8 x i32> <i32 0, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>, <8 x i32> [[TMP7]], <8 x i32> <i32 0, i32 9, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP9:%.*]] = shufflevector <2 x i32> [[TMP2]], <2 x i32> poison, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP10:%.*]] = shufflevector <8 x i32> [[TMP8]], <8 x i32> [[TMP9]], <8 x i32> <i32 0, i32 1, i32 8, i32 9, i32 4, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP11:%.*]] = shufflevector <2 x i32> [[TMP3]], <2 x i32> poison, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP27:%.*]] = shufflevector <8 x i32> [[TMP10]], <8 x i32> [[TMP11]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 6, i32 7>
-; CHECK-NEXT: [[TMP30:%.*]] = shufflevector <2 x i32> [[TMP5]], <2 x i32> poison, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
+; CHECK-NEXT: [[TMP6:%.*]] = insertelement <8 x i32> <i32 0, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>, i32 [[TMP22:%.*]], i32 1
+; CHECK-NEXT: [[TMP7:%.*]] = shufflevector <4 x i32> [[TMP3]], <4 x i32> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
+; CHECK-NEXT: [[TMP27:%.*]] = shufflevector <8 x i32> [[TMP6]], <8 x i32> [[TMP7]], <8 x i32> <i32 0, i32 1, i32 8, i32 9, i32 10, i32 11, i32 poison, i32 poison>
+; CHECK-NEXT: [[TMP30:%.*]] = shufflevector <2 x i32> [[TMP5]], <2 x i32> poison, <8 x i32> <i32 1, i32 0, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
; CHECK-NEXT: [[TMP31:%.*]] = shufflevector <8 x i32> [[TMP27]], <8 x i32> [[TMP30]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 8, i32 9>
; CHECK-NEXT: br i1 false, label %[[IF_END24:.*]], label %[[IF_THEN11:.*]]
; CHECK: [[IF_THEN11]]:
-; CHECK-NEXT: [[TMP12:%.*]] = shufflevector <2 x i32> [[TMP4]], <2 x i32> poison, <8 x i32> <i32 poison, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP13:%.*]] = shufflevector <2 x i32> [[TMP4]], <2 x i32> poison, <8 x i32> <i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT: [[TMP14:%.*]] = shufflevector <8 x i32> [[TMP13]], <8 x i32> <i32 0, i32 poison, i32 0, i32 0, i32 0, i32 0, i32 0, i32 poison>, <8 x i32> <i32 8, i32 1, i32 10, i32 11, i32 12, i32 13, i32 14, i32 poison>
-; CHECK-NEXT: [[TMP15:%.*]] = insertelement <8 x i32> poison, i32 [[J_4]], i32 0
-; CHECK-NEXT: [[TMP16:%.*]] = shufflevector <8 x i32> [[TMP15]], <8 x i32> poison, <8 x i32> <i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 0>
-; CHECK-NEXT: [[TMP29:%.*]] = shufflevector <8 x i32> [[TMP14]], <8 x i32> [[TMP16]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 15>
+; CHECK-NEXT: [[TMP11:%.*]] = shufflevector <2 x i32> [[TMP2]], <2 x i32> poison, <8 x i32> <i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 0, i32 poison>
+; CHECK-NEXT: [[TMP12:%.*]] = shufflevector <8 x i32> <i32 0, i32 poison, i32 0, i32 0, i32 0, i32 0, i32 0, i32 poison>, <8 x i32> [[TMP11]], <8 x i32> <i32 0, i32 8, i32 2, i32 3, i32 4, i32 5, i32 6, i32 14>
; CHECK-NEXT: br label %[[IF_END24]]
; CHECK: [[IF_THEN18:.*]]:
; CHECK-NEXT: br label %[[T]]
; CHECK: [[T]]:
-; CHECK-NEXT: [[TMP34:%.*]] = phi <8 x i32> [ [[TMP33:%.*]], %[[O]] ], [ poison, %[[IF_THEN18]] ]
+; CHECK-NEXT: [[TMP13:%.*]] = phi <8 x i32> [ [[TMP33:%.*]], %[[O]] ], [ poison, %[[IF_THEN18]] ]
; CHECK-NEXT: [[TMP17]] = extractelement <4 x i32> [[TMP23:%.*]], i32 0
; CHECK-NEXT: br i1 false, label %[[IF_END24]], label %[[K]]
; CHECK: [[IF_END24]]:
-; CHECK-NEXT: [[TMP18:%.*]] = phi <8 x i32> [ [[TMP29]], %[[IF_THEN11]] ], [ [[TMP31]], %[[IF_END6]] ], [ [[TMP34]], %[[T]] ]
-; CHECK-NEXT: [[TMP19:%.*]] = shufflevector <8 x i32> [[TMP18]], <8 x i32> poison, <2 x i32> <i32 7, i32 1>
+; CHECK-NEXT: [[TMP18:%.*]] = phi <8 x i32> [ [[TMP12]], %[[IF_THEN11]] ], [ [[TMP31]], %[[IF_END6]] ], [ [[TMP13]], %[[T]] ]
; CHECK-NEXT: [[TMP20:%.*]] = shufflevector <8 x i32> [[TMP18]], <8 x i32> poison, <4 x i32> <i32 0, i32 5, i32 6, i32 7>
-; CHECK-NEXT: [[TMP21:%.*]] = shufflevector <8 x i32> [[TMP18]], <8 x i32> poison, <4 x i32> <i32 2, i32 3, i32 4, i32 6>
+; CHECK-NEXT: [[TMP19:%.*]] = shufflevector <8 x i32> [[TMP18]], <8 x i32> poison, <2 x i32> <i32 6, i32 1>
+; CHECK-NEXT: [[TMP34:%.*]] = shufflevector <8 x i32> [[TMP18]], <8 x i32> poison, <4 x i32> <i32 2, i32 3, i32 4, i32 7>
; CHECK-NEXT: br label %[[O]]
; CHECK: [[O]]:
-; CHECK-NEXT: [[TMP22]] = phi <2 x i32> [ zeroinitializer, %[[K]] ], [ [[TMP19]], %[[IF_END24]] ]
; CHECK-NEXT: [[TMP23]] = phi <4 x i32> [ [[TMP1]], %[[K]] ], [ [[TMP20]], %[[IF_END24]] ]
-; CHECK-NEXT: [[TMP24:%.*]] = phi <4 x i32> [ zeroinitializer, %[[K]] ], [ [[TMP21]], %[[IF_END24]] ]
+; CHECK-NEXT: [[TMP24]] = phi <2 x i32> [ zeroinitializer, %[[K]] ], [ [[TMP19]], %[[IF_END24]] ]
+; CHECK-NEXT: [[TMP21:%.*]] = phi <4 x i32> [ zeroinitializer, %[[K]] ], [ [[TMP34]], %[[IF_END24]] ]
+; CHECK-NEXT: [[TMP22]] = extractelement <2 x i32> [[TMP24]], i32 1
; CHECK-NEXT: [[TMP25:%.*]] = shufflevector <4 x i32> [[TMP23]], <4 x i32> poison, <8 x i32> <i32 0, i32 poison, i32 0, i32 0, i32 poison, i32 poison, i32 poison, i32 poison>
; CHECK-NEXT: [[TMP26:%.*]] = shufflevector <8 x i32> [[TMP25]], <8 x i32> <i32 poison, i32 0, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>, <8 x i32> <i32 0, i32 9, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
; CHECK-NEXT: [[TMP32:%.*]] = shufflevector <4 x i32> [[TMP23]], <4 x i32> poison, <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison>
; CHECK-NEXT: [[TMP33]] = shufflevector <8 x i32> [[TMP26]], <8 x i32> [[TMP32]], <8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 8, i32 9, i32 10, i32 11>
-; CHECK-NEXT: [[TMP28]] = extractelement <4 x i32> [[TMP24]], i32 3
+; CHECK-NEXT: [[TMP35:%.*]] = shufflevector <2 x i32> [[TMP24]], <2 x i32> poison, <2 x i32> <i32 1, i32 poison>
+; CHECK-NEXT: [[TMP28:%.*]] = shufflevector <4 x i32> [[TMP21]], <4 x i32> poison, <2 x i32> <i32 poison, i32 3>
+; CHECK-NEXT: [[TMP29]] = shufflevector <2 x i32> [[TMP35]], <2 x i32> [[TMP28]], <2 x i32> <i32 0, i32 3>
; CHECK-NEXT: br i1 false, label %[[T]], label %[[IF_END6]]
;
entry:
``````````
</details>
https://github.com/llvm/llvm-project/pull/149209
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