[llvm-branch-commits] [llvm] release/18.x: [TSan] Fix atomicrmw xchg with pointer and floats (#85228) (PR #85371)

[via llvm-branch-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

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

Author: None (llvmbot)

<details>
<summary>Changes</summary>

Backport ff2fb2a1d78585944dcdb9061c8487fe1476dfa4

Requested by: @<!-- -->nikic

---
Full diff: https://github.com/llvm/llvm-project/pull/85371.diff


2 Files Affected:

- (modified) llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp (+5-4) 
- (modified) llvm/test/Instrumentation/ThreadSanitizer/atomic.ll (+20) 


``````````diff
diff --git a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
index 8ee0bca7e354f0..0f42ff79086994 100644
--- a/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/ThreadSanitizer.cpp
@@ -752,11 +752,12 @@ bool ThreadSanitizer::instrumentAtomic(Instruction *I, const DataLayout &DL) {
     const unsigned ByteSize = 1U << Idx;
     const unsigned BitSize = ByteSize * 8;
     Type *Ty = Type::getIntNTy(IRB.getContext(), BitSize);
-    Value *Args[] = {Addr,
-                     IRB.CreateIntCast(RMWI->getValOperand(), Ty, false),
+    Value *Val = RMWI->getValOperand();
+    Value *Args[] = {Addr, IRB.CreateBitOrPointerCast(Val, Ty),
                      createOrdering(&IRB, RMWI->getOrdering())};
-    CallInst *C = CallInst::Create(F, Args);
-    ReplaceInstWithInst(I, C);
+    Value *C = IRB.CreateCall(F, Args);
+    I->replaceAllUsesWith(IRB.CreateBitOrPointerCast(C, Val->getType()));
+    I->eraseFromParent();
   } else if (AtomicCmpXchgInst *CASI = dyn_cast<AtomicCmpXchgInst>(I)) {
     Value *Addr = CASI->getPointerOperand();
     Type *OrigOldValTy = CASI->getNewValOperand()->getType();
diff --git a/llvm/test/Instrumentation/ThreadSanitizer/atomic.ll b/llvm/test/Instrumentation/ThreadSanitizer/atomic.ll
index 76afc4bf007c2d..8b387cd4962979 100644
--- a/llvm/test/Instrumentation/ThreadSanitizer/atomic.ll
+++ b/llvm/test/Instrumentation/ThreadSanitizer/atomic.ll
@@ -78,6 +78,26 @@ entry:
 ; CHECK-LABEL: atomic8_xchg_monotonic
 ; CHECK: call i8 @__tsan_atomic8_exchange(ptr %a, i8 0, i32 0), !dbg
 
+define void @atomic8_xchg_monotonic_ptr(ptr %a, ptr %b) nounwind uwtable {
+entry:
+  atomicrmw xchg ptr %a, ptr %b monotonic, !dbg !7
+  ret void, !dbg !7
+}
+; CHECK-LABEL: atomic8_xchg_monotonic_ptr
+; CHECK: [[ARG:%.*]] = ptrtoint ptr %b to i64, !dbg
+; CHECK: [[RES:%.*]] = call i64 @__tsan_atomic64_exchange(ptr %a, i64 [[ARG]], i32 0), !dbg
+; CHECK: [[CAST:%.*]] = inttoptr i64 [[RES]] to ptr, !dbg
+
+define void @atomic8_xchg_monotonic_float(ptr %a, float %b) nounwind uwtable {
+entry:
+  atomicrmw xchg ptr %a, float %b monotonic, !dbg !7
+  ret void, !dbg !7
+}
+; CHECK-LABEL: atomic8_xchg_monotonic_float
+; CHECK: [[ARG:%.*]] = bitcast float %b to i32, !dbg
+; CHECK: [[RES:%.*]] = call i32 @__tsan_atomic32_exchange(ptr %a, i32 [[ARG]], i32 0), !dbg
+; CHECK: [[CAST:%.*]] = bitcast i32 [[RES]] to float, !dbg
+
 define void @atomic8_add_monotonic(ptr %a) nounwind uwtable {
 entry:
   atomicrmw add ptr %a, i8 0 monotonic, !dbg !7

``````````

</details>


https://github.com/llvm/llvm-project/pull/85371