[llvm] [SLP] Fix incorrect convert when interchangeable instruction is used. (PR #132887)
via llvm-commits
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Mon Mar 24 23:09:23 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-transforms
Author: Han-Kuan Chen (HanKuanChen)
<details>
<summary>Changes</summary>
If the Converter has AltOp, that means I should be converted to AltOp
instead of MainOp (which is AltOp in BinOpSameOpcodeHelper).
---
Full diff: https://github.com/llvm/llvm-project/pull/132887.diff
2 Files Affected:
- (modified) llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp (+3-6)
- (added) llvm/test/Transforms/SLPVectorizer/X86/BinOpSameOpcodeHelper.ll (+36)
``````````diff
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
index 72e18be9fe71e..6d96aedc5ff9f 100644
--- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
+++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp
@@ -1094,12 +1094,9 @@ class BinOpSameOpcodeHelper {
unsigned getAltOpcode() const {
return hasAltOp() ? AltOp.getOpcode() : getMainOpcode();
}
- SmallVector<Value *> getMainOperand(Instruction *I) const {
+ SmallVector<Value *> getOperand(Instruction *I) const {
return MainOp.getOperand(I);
}
- SmallVector<Value *> getAltOperand(Instruction *I) const {
- return AltOp.getOperand(I);
- }
};
bool isConvertible(Instruction *I, Instruction *MainOp, Instruction *AltOp) {
@@ -1126,8 +1123,8 @@ convertTo(Instruction *I, Instruction *MainOp, Instruction *AltOp) {
assert(I->isBinaryOp() && "Cannot convert the instruction.");
BinOpSameOpcodeHelper Converter(I);
if (Converter.add(I) && Converter.add(MainOp) && !Converter.hasAltOp())
- return std::make_pair(MainOp, Converter.getMainOperand(MainOp));
- return std::make_pair(AltOp, Converter.getAltOperand(AltOp));
+ return std::make_pair(MainOp, Converter.getOperand(MainOp));
+ return std::make_pair(AltOp, Converter.getOperand(AltOp));
}
/// Main data required for vectorization of instructions.
diff --git a/llvm/test/Transforms/SLPVectorizer/X86/BinOpSameOpcodeHelper.ll b/llvm/test/Transforms/SLPVectorizer/X86/BinOpSameOpcodeHelper.ll
new file mode 100644
index 0000000000000..6f27555aeb3f1
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/X86/BinOpSameOpcodeHelper.ll
@@ -0,0 +1,36 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -mtriple=x86_64-unknown-linux-gnu -passes=slp-vectorizer -S %s | FileCheck %s
+
+define void @test() {
+; CHECK-LABEL: @test(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[TMP0:%.*]] = lshr i64 0, 0
+; CHECK-NEXT: [[TMP1:%.*]] = sub i64 0, 1
+; CHECK-NEXT: [[TMP2:%.*]] = lshr i64 [[TMP1]], 0
+; CHECK-NEXT: [[UMIN120:%.*]] = call i64 @llvm.umin.i64(i64 [[TMP0]], i64 [[TMP2]])
+; CHECK-NEXT: [[TMP3:%.*]] = sub i64 0, 0
+; CHECK-NEXT: [[TMP4:%.*]] = lshr i64 [[TMP3]], 0
+; CHECK-NEXT: [[UMIN122:%.*]] = call i64 @llvm.umin.i64(i64 [[UMIN120]], i64 [[TMP4]])
+; CHECK-NEXT: [[TMP5:%.*]] = add i64 0, 1
+; CHECK-NEXT: [[TMP6:%.*]] = lshr i64 [[TMP5]], 0
+; CHECK-NEXT: [[UMIN123:%.*]] = call i64 @llvm.umin.i64(i64 [[UMIN122]], i64 [[TMP6]])
+; CHECK-NEXT: [[UMIN124:%.*]] = call i64 @llvm.umin.i64(i64 [[UMIN123]], i64 0)
+; CHECK-NEXT: ret void
+;
+entry:
+ %0 = mul i64 0, 0
+ %1 = lshr i64 %0, 0
+ %2 = sub i64 0, 1
+ %3 = lshr i64 %2, 0
+ %umin120 = call i64 @llvm.umin.i64(i64 %1, i64 %3)
+ %4 = sub i64 0, 0
+ %5 = lshr i64 %4, 0
+ %umin122 = call i64 @llvm.umin.i64(i64 %umin120, i64 %5)
+ %6 = add i64 0, 1
+ %7 = lshr i64 %6, 0
+ %umin123 = call i64 @llvm.umin.i64(i64 %umin122, i64 %7)
+ %umin124 = call i64 @llvm.umin.i64(i64 %umin123, i64 0)
+ ret void
+}
+
+declare i64 @llvm.umin.i64(i64, i64)
``````````
</details>
https://github.com/llvm/llvm-project/pull/132887
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