1 files changed, 41 insertions, 0 deletions
diff --git a/llvm/test/Instrumentation/DataFlowSanitizer/union.ll b/llvm/test/Instrumentation/DataFlowSanitizer/union.ll
new file mode 100644
index 00000000000..30162e75a25
--- /dev/null
+++ b/llvm/test/Instrumentation/DataFlowSanitizer/union.ll
@@ -0,0 +1,41 @@
+; RUN: opt < %s -dfsan -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"
+
+@a = common global i32 0
+@b = common global i32 0
+
+; Check that we reuse unions where possible.
+
+; CHECK-LABEL: @"dfs$f"
+define void @f(i32 %x, i32 %y) {
+  ; CHECK: __dfsan_union
+  %xay = add i32 %x, %y
+  store i32 %xay, i32* @a
+  ; CHECK-NOT: __dfsan_union
+  %xmy = mul i32 %x, %y
+  store i32 %xmy, i32* @b
+  ret void
+}
+
+; In this case, we compute the unions on both sides because neither block
+; dominates the other.
+
+; CHECK-LABEL: @"dfs$g"
+define void @g(i1 %p, i32 %x, i32 %y) {
+  br i1 %p, label %l1, label %l2
+
+l1:
+  ; CHECK: __dfsan_union
+  %xay = add i32 %x, %y
+  store i32 %xay, i32* @a
+  br label %l3
+
+l2:
+  ; CHECK: __dfsan_union
+  %xmy = mul i32 %x, %y
+  store i32 %xmy, i32* @b
+  br label %l3
+
+l3:
+  ret void
+}