add a testcase for a bug Duncan pointed out.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46372 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/test/CFrontend/2008-01-25-ByValReadNone.c b/test/CFrontend/2008-01-25-ByValReadNone.c
new file mode 100644 (file)
index 0000000..afbf970
--- /dev/null
+++ b/test/CFrontend/2008-01-25-ByValReadNone.c
@@ -0,0 +1,10 @@
+// RUN: %llvmgcc -O3 -S -o - -emit-llvm %s | grep readonly
+// RUN: %llvmgcc -O3 -S -o - -emit-llvm %s | not grep readnone
+
+
+// The struct being passed byval means that we need to mark the 
+// function readonly instead of readnone.  Readnone would allow
+// stores to the arg to be deleted in the caller.
+struct S { int A[1000]; };
+int __attribute__ ((const)) f(struct S x) { return x.A[0]; }
+