[Bug middle-end/48590] Alias analysis confused by builtin-stack-save/restore

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48590

--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-04-13 11:13:14 UTC ---
The following should be safe (but doesn't try to address the dead code
elimination issue).


Index: gcc/tree-ssa-alias.c
===================================================================
--- gcc/tree-ssa-alias.c    (revision 170321)
+++ gcc/tree-ssa-alias.c    (working copy)
@@ -1432,6 +1432,9 @@ call_may_clobber_ref_p_1 (gimple call, a
         tree ptr = gimple_call_arg (call, 0);
         return ptr_deref_may_alias_ref_p_1 (ptr, ref);
       }
+    case BUILT_IN_STACK_SAVE:
+    case BUILT_IN_STACK_RESTORE:
+      return false;
     case BUILT_IN_GAMMA_R:
     case BUILT_IN_GAMMAF_R:
     case BUILT_IN_GAMMAL_R: