[llvm] [TSan] Fix missing inst cleanup (PR #144067)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Kunqiu Chen (Camsyn)

<details>
<summary>Changes</summary>

Commit 44e875ad5b2ce26826dd53f9e7d1a71436c86212 introduced a change that replaces `ReplaceInstWithInst` with `Instruction::replaceAllUsesWith`, without subsequent instruction cleanup.

This results in TSan leaving behind useless `load atomic` instructions after 'replacing' them.

This commit adds cleanup back, consistent with the context.

---
Full diff: https://github.com/llvm/llvm-project/pull/144067.diff


1 Files Affected:

- (modified) llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp (+1) 


``````````diff
diff --git a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index ec9f78edfeb1c..195a157ee20af 100644
--- a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -729,6 +729,7 @@ bool ThreadSanitizer::instrumentAtomic(Instruction *I, const DataLayout &DL) {
     Value *C = IRB.CreateCall(TsanAtomicLoad[Idx], Args);
     Value *Cast = IRB.CreateBitOrPointerCast(C, OrigTy);
     I->replaceAllUsesWith(Cast);
+    I->eraseFromParent();
   } else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
     Value *Addr = SI->getPointerOperand();
     int Idx =

``````````

</details>


https://github.com/llvm/llvm-project/pull/144067