[llvm] 355725a - [TSan] Fix missing inst cleanup (#144067)

[via llvm-commits]

Author: Kunqiu Chen
Date: 2025-06-18T17:09:32+08:00
New Revision: 355725a25e6be38d7a97cab9e206d2a16a1bd849

URL: https://github.com/llvm/llvm-project/commit/355725a25e6be38d7a97cab9e206d2a16a1bd849
DIFF: https://github.com/llvm/llvm-project/commit/355725a25e6be38d7a97cab9e206d2a16a1bd849.diff

LOG: [TSan] Fix missing inst cleanup (#144067)

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.

Added: 
    

Modified: 
    llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
    llvm/test/Instrumentation/ThreadSanitizer/atomic-non-integer.ll

Removed: 
    


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diff  --git a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index 8ae6f7745a9e7..5485998164f1e 100644
--- a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -728,6 +728,7 @@ 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 =

diff  --git a/llvm/test/Instrumentation/ThreadSanitizer/atomic-non-integer.ll b/llvm/test/Instrumentation/ThreadSanitizer/atomic-non-integer.ll
index 8bcabaecf0fdc..015ee2fe711e1 100644
--- a/llvm/test/Instrumentation/ThreadSanitizer/atomic-non-integer.ll
+++ b/llvm/test/Instrumentation/ThreadSanitizer/atomic-non-integer.ll
@@ -10,7 +10,6 @@ define float @load_float(ptr %fptr) {
 ; CHECK-NEXT:    call void @__tsan_func_entry(ptr [[TMP1]])
 ; CHECK-NEXT:    [[TMP2:%.*]] = call i32 @__tsan_atomic32_load(ptr [[FPTR]], i32 0)
 ; CHECK-NEXT:    [[TMP3:%.*]] = bitcast i32 [[TMP2]] to float
-; CHECK-NEXT:    [[V:%.*]] = load atomic float, ptr [[FPTR]] unordered, align 4
 ; CHECK-NEXT:    call void @__tsan_func_exit()
 ; CHECK-NEXT:    ret float [[TMP3]]
 ;
@@ -25,7 +24,6 @@ define double @load_double(ptr %fptr) {
 ; CHECK-NEXT:    call void @__tsan_func_entry(ptr [[TMP1]])
 ; CHECK-NEXT:    [[TMP2:%.*]] = call i64 @__tsan_atomic64_load(ptr [[FPTR]], i32 0)
 ; CHECK-NEXT:    [[TMP3:%.*]] = bitcast i64 [[TMP2]] to double
-; CHECK-NEXT:    [[V:%.*]] = load atomic double, ptr [[FPTR]] unordered, align 8
 ; CHECK-NEXT:    call void @__tsan_func_exit()
 ; CHECK-NEXT:    ret double [[TMP3]]
 ;
@@ -40,7 +38,6 @@ define fp128 @load_fp128(ptr %fptr) {
 ; CHECK-NEXT:    call void @__tsan_func_entry(ptr [[TMP1]])
 ; CHECK-NEXT:    [[TMP2:%.*]] = call i128 @__tsan_atomic128_load(ptr [[FPTR]], i32 0)
 ; CHECK-NEXT:    [[TMP3:%.*]] = bitcast i128 [[TMP2]] to fp128
-; CHECK-NEXT:    [[V:%.*]] = load atomic fp128, ptr [[FPTR]] unordered, align 16
 ; CHECK-NEXT:    call void @__tsan_func_exit()
 ; CHECK-NEXT:    ret fp128 [[TMP3]]
 ;