1 files changed, 32 insertions, 0 deletions
diff --git a/test/Instrumentation/ThreadSanitizer/read_before_write.ll b/test/Instrumentation/ThreadSanitizer/read_before_write.ll
new file mode 100644
index 0000000000..482362aa7d
--- /dev/null
+++ b/test/Instrumentation/ThreadSanitizer/read_before_write.ll
@@ -0,0 +1,32 @@
+; RUN: opt < %s -tsan -S | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+
+define void @IncrementMe(i32* nocapture %ptr) nounwind uwtable {
+entry:
+  %0 = load i32* %ptr, align 4
+  %inc = add nsw i32 %0, 1
+  store i32 %inc, i32* %ptr, align 4
+  ret void
+}
+; CHECK: define void @IncrementMe
+; CHECK-NOT: __tsan_read
+; CHECK: __tsan_write
+; CHECK: ret void
+
+define void @IncrementMeWithCallInBetween(i32* nocapture %ptr) nounwind uwtable {
+entry:
+  %0 = load i32* %ptr, align 4
+  %inc = add nsw i32 %0, 1
+  call void @foo()
+  store i32 %inc, i32* %ptr, align 4
+  ret void
+}
+
+; CHECK: define void @IncrementMeWithCallInBetween
+; CHECK: __tsan_read
+; CHECK: __tsan_write
+; CHECK: ret void
+
+declare void @foo()
+