1 files changed, 16 insertions, 0 deletions
diff --git a/clang/test/CodeGen/2008-01-25-ByValReadNone.c b/clang/test/CodeGen/2008-01-25-ByValReadNone.c
new file mode 100644
index 0000000..06ad1ee
--- /dev/null
+++ b/clang/test/CodeGen/2008-01-25-ByValReadNone.c
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -emit-llvm -o - %s | not grep readonly
+// RUN: %clang_cc1 -emit-llvm -o - %s | not grep readnone
+
+// XFAIL: arm
+
+// The struct being passed byval means that we cannot mark the
+// function readnone.  Readnone would allow stores to the arg to
+// be deleted in the caller.  We also don't allow readonly since
+// the callee might write to the byval parameter.  The inliner
+// would have to assume the worse and introduce an explicit
+// temporary when inlining such a function, which is costly for
+// the common case in which the byval argument is not written.
+struct S { int A[1000]; };
+int __attribute__ ((const)) f(struct S x) { x.A[1] = 0; return x.A[0]; }
+int g(struct S x) __attribute__ ((pure));
+int h(struct S x) { return g(x); }