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authorKostya Serebryany <kcc@google.com>2012-04-10 18:18:56 +0000
committerKostya Serebryany <kcc@google.com>2012-04-10 18:18:56 +0000
commit2076af0184bd38185a719ea07cb10a90e8565a89 (patch)
tree539c661f5cf55768452c59ba10992183d7f88fed /test
parent18112d83e7d54597bcd5870fb411c7997e02bc1e (diff)
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[tsan] compile-time instrumentation: do not instrument a read if
a write to the same temp follows in the same BB. Also add stats printing. On Spec CPU2006 this optimization saves roughly 4% of instrumented reads (which is 3% of all instrumented accesses): Writes : 161216 Reads : 446458 Reads-before-write: 18295 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154418 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test')
-rw-r--r--test/Instrumentation/ThreadSanitizer/read_before_write.ll32
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 0000000..482362a
--- /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()
+