[Bug middle-end/60092] posix_memalign not recognized to derive alias and alignment info

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60092

--- Comment #12 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Andreas Schwab from comment #11)
> If a function is not allowed to change errno this must be explicitly
> documented.

That means

Index: gcc/tree-ssa-alias.c
===================================================================
--- gcc/tree-ssa-alias.c.orig   2014-02-06 15:43:42.138266256 +0100
+++ gcc/tree-ssa-alias.c        2014-02-06 15:43:33.046266882 +0100
@@ -1847,7 +1847,9 @@ call_may_clobber_ref_p_1 (gimple call, a
            ao_ref dref;
            ao_ref_init_from_ptr_and_size (&dref, ptrptr,
                                           TYPE_SIZE_UNIT (ptr_type_node));
-           return refs_may_alias_p_1 (&dref, ref, false);
+           return (refs_may_alias_p_1 (&dref, ref, false)
+                   || (flag_errno_math
+                       && targetm.ref_may_alias_errno (ref)));
          }
        /* Freeing memory kills the pointed-to memory.  More importantly
           the call has to serve as a barrier for moving loads and stores

is necessary.