[llvm] 38e64b1 - [SLP]Fix minbiwidth analysis for gather nodes with SIToFP users

[Alexey Bataev via llvm-commits]

Author: Alexey Bataev
Date: 2025-04-11T11:40:41-07:00
New Revision: 38e64b1a84d1af0bb232833f8f6f57bd4d6e8a7a

URL: https://github.com/llvm/llvm-project/commit/38e64b1a84d1af0bb232833f8f6f57bd4d6e8a7a
DIFF: https://github.com/llvm/llvm-project/commit/38e64b1a84d1af0bb232833f8f6f57bd4d6e8a7a.diff

LOG: [SLP]Fix minbiwidth analysis for gather nodes with SIToFP users

If the buildvector node has cast to float user, it cannot be considered as safe
for truncation, need to use the original bitwidth here.

Fixes #135410

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
    llvm/test/Transforms/SLPVectorizer/X86/trunced-buildvector-scalar-extended.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index b7ee5bfc310d9..50c403906daa9 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -19974,8 +19974,10 @@ void BoUpSLP::computeMinimumValueSizes() {
                       return false;
                     if (!isa<CastInst, BinaryOperator, FreezeInst, PHINode,
                              SelectInst>(U) ||
+                        isa<SIToFPInst, UIToFPInst>(U) ||
                         !isa<CastInst, BinaryOperator, FreezeInst, PHINode,
-                             SelectInst>(UserTE->getMainOp()))
+                             SelectInst>(UserTE->getMainOp()) ||
+                        isa<SIToFPInst, UIToFPInst>(UserTE->getMainOp()))
                       return true;
                     unsigned UserTESz = DL->getTypeSizeInBits(
                         UserTE->Scalars.front()->getType());

diff  --git a/llvm/test/Transforms/SLPVectorizer/X86/trunced-buildvector-scalar-extended.ll b/llvm/test/Transforms/SLPVectorizer/X86/trunced-buildvector-scalar-extended.ll
index 29aed14dc3ffc..ffeb8045dea7e 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/trunced-buildvector-scalar-extended.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/trunced-buildvector-scalar-extended.ll
@@ -5,9 +5,8 @@ define <4 x float> @test(i64 %0) {
 ; CHECK-LABEL: define <4 x float> @test(
 ; CHECK-SAME: i64 [[TMP0:%.*]]) {
 ; CHECK-NEXT:  [[ENTRY:.*:]]
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[TMP0]] to i32
-; CHECK-NEXT:    [[TMP2:%.*]] = insertelement <4 x i32> <i32 0, i32 0, i32 poison, i32 0>, i32 [[TMP1]], i32 2
-; CHECK-NEXT:    [[TMP3:%.*]] = sext <4 x i32> [[TMP2]] to <4 x i64>
+; CHECK-NEXT:    [[TMP3:%.*]] = insertelement <4 x i64> <i64 0, i64 0, i64 poison, i64 0>, i64 [[TMP0]], i32 2
+; CHECK-NEXT:    [[TMP2:%.*]] = trunc <4 x i64> [[TMP3]] to <4 x i32>
 ; CHECK-NEXT:    [[TMP4:%.*]] = sitofp <4 x i64> [[TMP3]] to <4 x float>
 ; CHECK-NEXT:    [[TMP5:%.*]] = sitofp <4 x i32> [[TMP2]] to <4 x float>
 ; CHECK-NEXT:    [[TMP6:%.*]] = fadd <4 x float> [[TMP4]], [[TMP5]]