Merge branch 'master' of ssh://bitbucket.org/czan/honours

1 files changed, 53 insertions, 0 deletions

diff --git a/clang/test/CodeGen/byval-memcpy-elim.c b/clang/test/CodeGen/byval-memcpy-elim.c
new file mode 100644
index 0000000..76cdafb
--- /dev/null
+++ b/clang/test/CodeGen/byval-memcpy-elim.c
@@ -0,0 +1,53 @@
+// RUN: %clang_cc1 -emit-llvm -triple x86_64-apple-darwin10 < %s | FileCheck %s
+
+struct Test1S {
+ long NumDecls;
+ long X;
+ long Y;
+};
+struct Test2S {
+ long NumDecls;
+ long X;
+};
+
+// Make sure we don't generate extra memcpy for lvalues
+void test1a(struct Test1S, struct Test2S);
+// CHECK: define void @test1(
+// CHECK-NOT: memcpy
+// CHECK: call void @test1a
+void test1(struct Test1S *A, struct Test2S *B) {
+  test1a(*A, *B);
+}
+
+// The above gets tricker when the byval argument requires higher alignment
+// than the natural alignment of the type in question.
+// rdar://9483886
+
+// Make sure we do generate a memcpy when we cannot guarantee alignment.
+struct Test3S {
+  int a,b,c,d,e,f,g,h,i,j,k,l;
+};
+void test2a(struct Test3S q);
+// CHECK: define void @test2(
+// CHECK: alloca %struct.Test3S, align 8
+// CHECK: memcpy
+// CHECK: call void @test2a
+void test2(struct Test3S *q) {
+  test2a(*q);
+}
+
+// But make sure we don't generate a memcpy when we can guarantee alignment.
+void fooey(void);
+// CHECK: define void @test3(
+// CHECK: alloca %struct.Test3S, align 8
+// CHECK: call void @fooey
+// CHECK-NOT: memcpy
+// CHECK: call void @test2a
+// CHECK-NOT: memcpy
+// CHECK: call void @test2a
+void test3(struct Test3S a) {
+  struct Test3S b = a;
+  fooey();
+  test2a(a);
+  test2a(b);
+}