Patch to optimize away copy constructor call when

appropriate.

llvm-svn: 78267

1 files changed, 31 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/copy-constructor-elim.cpp b/clang/test/CodeGenCXX/copy-constructor-elim.cpp
new file mode 100644
index 00000000000..5a1109d7f75
--- /dev/null
+++ b/clang/test/CodeGenCXX/copy-constructor-elim.cpp
@@ -0,0 +1,31 @@
+// RUN: clang-cc -emit-llvm -o %t %s &&
+// RUN: grep "_ZN1CC1ERK1C" %t | count 0
+
+extern "C" int printf(...);
+
+
+struct C {
+	C() : iC(6) {printf("C()\n"); }
+	C(const C& c) { printf("C(const C& c)\n"); }
+	int iC;
+};
+
+C foo() {
+  return C();
+};
+
+class X { // ...
+public: 
+	X(int) {}
+	X(const X&, int i = 1, int j = 2, C c = foo()) {
+		printf("X(const X&, %d, %d, %d)\n", i, j, c.iC);
+	}
+};
+
+int main()
+{
+	X a(1);
+	X b(a, 2);
+	X c = b;
+	X d(a, 5, 6);
+}