[PATCH][4.3] Avoid false positives in alias warnings, fix werror bootstrap

[PATCH][4.3] Avoid false positives in alias warnings, fix werror bootstrap

[Richard Guenther]

This fixes --enable-werror bootstrap on the 4.3 branch which was broken
a little bit more by the alias-pruning fix.  We should not rely on
points-to sets we merged aliases of SMTs into (which basically says
"gee - whatever this points to").  This also fixes a missing initializer
caused by Ulis backport of the round-towards-zero patches.

Bootstrapped and tested on x86_64-unknown-linux-gnu (with 
--enable-werror), applied to the branch.

Richard.

2008-10-22  Richard Guenther  <rguenther@suse.de>

	* tree-ssa-alias-warnings.c (skip_this_pointer): Skip pointers
	for which we merged aliases of SMTs into their points-to sets.
	* real.c (vax_f_format): Add missing initializer.

Index: gcc/tree-ssa-alias-warnings.c
===================================================================
*** gcc/tree-ssa-alias-warnings.c	(revision 141290)
--- gcc/tree-ssa-alias-warnings.c	(working copy)
*************** skip_this_pointer (tree ptr ATTRIBUTE_UN
*** 896,902 ****
      return true;
  
    /* This would probably cause too many false positives.  */
!   if (pi->value_escapes_p || pi->pt_anything)
      return true;
  
    return false;
--- 896,902 ----
      return true;
  
    /* This would probably cause too many false positives.  */
!   if (pi->value_escapes_p || pi->pt_anything || pi->pt_global_mem)
      return true;
  
    return false;
Index: gcc/real.c
===================================================================
*** gcc/real.c	(revision 141290)
--- gcc/real.c	(working copy)
*************** const struct real_format vax_f_format =
*** 4218,4223 ****
--- 4218,4224 ----
      false,
      false,
      false,
+     false,
      false
    };