diff gcc/testsuite/gcc.dg/nrv4.c @ 111:04ced10e8804

gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/nrv4.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,32 @@
+/* Verify that NRV optimizations are prohibited when the LHS is an
+   indirect reference to something that may be call-clobbered. */
+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-optimized" } */
+
+typedef struct { int x[20]; void *y; } S;
+S nrv_candidate (void);
+void use_result (S);
+void make_escape (S *);
+S global_S;
+void foo (void)
+{
+  S *result;
+  S local_S;
+
+  /* We can't perform return slot optimization because global_S is
+     global and may be clobbered by nrv_candidate.  */
+  result = &global_S;
+  *result = nrv_candidate ();
+  use_result (*result);
+
+  /* We can't perform return slot optimization because local_S is
+     call_clobbered (its address escapes prior to invoking
+     nrv_candidate).  */
+  make_escape (&local_S);
+  result = &local_S;
+  *result = nrv_candidate ();
+  use_result (*result);
+}
+
+/* { dg-final { scan-tree-dump-times "return slot optimization" 0 "optimized" } } */
+