[llvm] e78aa8f - [SLP]Use the size of gathered scalars when evaluating slice size

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2025-01-31T11:19:46-08:00
New Revision: e78aa8f35e6dd66d5152396406d3d4f37f43e7f4

URL: https://github.com/llvm/llvm-project/commit/e78aa8f35e6dd66d5152396406d3d4f37f43e7f4
DIFF: https://github.com/llvm/llvm-project/commit/e78aa8f35e6dd66d5152396406d3d4f37f43e7f4.diff

LOG: [SLP]Use the size of gathered scalars when evaluating slice size

Need to use the size of the gathered scalars, not the original size of
the buildvector scalars, since gathered scalar size might be changed
during building the buildvector shuffles.

Fixes #125259

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    llvm/test/Transforms/SLPVectorizer/X86/gathered-shuffle-resized.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 0a3f575915952f..1f7ab9fe01a73d 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -15094,7 +15094,7 @@ ResTy BoUpSLP::processBuildVector(const TreeEntry *E, Type *ScalarTy,
       }
     }
     if (!GatherShuffles.empty()) {
-      unsigned SliceSize = getPartNumElems(E->Scalars.size(), NumParts);
+      unsigned SliceSize = getPartNumElems(GatheredScalars.size(), NumParts);
       SmallVector<int> VecMask(Mask.size(), PoisonMaskElem);
       for (const auto [I, TEs] : enumerate(Entries)) {
         if (TEs.empty()) {

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/gathered-shuffle-resized.ll b/llvm/test/Transforms/SLPVectorizer/X86/gathered-shuffle-resized.ll
index f41d78516be640..48b04201d1acce 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/gathered-shuffle-resized.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/gathered-shuffle-resized.ll
@@ -18,9 +18,9 @@ define ptr @test(ptr %0, ptr %args_gep) {
 ; CHECK-NEXT:    [[TMP8:%.*]] = load i32, ptr [[TMP7]], align 4, !noalias [[META0:![0-9]+]]
 ; CHECK-NEXT:    [[TMP9:%.*]] = load <2 x i32>, ptr [[TMP6]], align 8, !noalias [[META0]]
 ; CHECK-NEXT:    [[TMP10:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> poison, <4 x i32> <i32 0, i32 1, i32 poison, i32 poison>
-; CHECK-NEXT:    [[TMP11:%.*]] = shufflevector <2 x i32> [[TMP9]], <2 x i32> poison, <16 x i32> poison
+; CHECK-NEXT:    [[TMP11:%.*]] = shufflevector <2 x i32> [[TMP9]], <2 x i32> poison, <16 x i32> <i32 poison, i32 poison, i32 0, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
 ; CHECK-NEXT:    [[TMP12:%.*]] = shufflevector <4 x i32> [[TMP10]], <4 x i32> poison, <16 x i32> <i32 0, i32 1, i32 2, i32 3, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
-; CHECK-NEXT:    [[TMP13:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> [[TMP9]], <16 x i32> <i32 0, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison, i32 poison>
+; CHECK-NEXT:    [[TMP13:%.*]] = shufflevector <2 x i32> [[TMP1]], <2 x i32> [[TMP9]], <16 x i32> <i32 0, i32 1, i32 1, i32 1, i32 1, i32 1, i32 1, i32 2, i32 2, i32 2, i32 2, i32 2, i32 2, i32 3, i32 3, i32 3>
 ; CHECK-NEXT:    [[TMP14:%.*]] = icmp eq <16 x i32> [[TMP13]], zeroinitializer
 ; CHECK-NEXT:    [[TMP15:%.*]] = zext <16 x i1> [[TMP14]] to <16 x i8>
 ; CHECK-NEXT:    store <16 x i8> [[TMP15]], ptr [[TMP5]], align 1