[PATCH] Fix PR44838

[PATCH] Fix PR44838

[Richard Guenther]

This fixes PR44838, a case that exposes that using SSA name equivalence
to derive value equivalence isn't valid in RTL.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2010-07-08  Richard Guenther  <rguenther@suse.de>

	PR rtl-optimization/44838
	* tree-ssa-alias.c (indirect_refs_may_alias_p): When not in
	SSA form do not use pointer equivalence.

Index: gcc/tree-ssa-alias.c
===================================================================
*** gcc/tree-ssa-alias.c	(revision 161913)
--- gcc/tree-ssa-alias.c	(working copy)
*************** indirect_refs_may_alias_p (tree ref1 ATT
*** 801,807 ****
    /* If both bases are based on pointers they cannot alias if they may not
       point to the same memory object or if they point to the same object
       and the accesses do not overlap.  */
!   if (operand_equal_p (ptr1, ptr2, 0))
      {
        if (TREE_CODE (base1) == MEM_REF)
  	offset1 += mem_ref_offset (base1).low * BITS_PER_UNIT;
--- 801,808 ----
    /* If both bases are based on pointers they cannot alias if they may not
       point to the same memory object or if they point to the same object
       and the accesses do not overlap.  */
!   if ((!cfun || gimple_in_ssa_p (cfun))
!       && operand_equal_p (ptr1, ptr2, 0))
      {
        if (TREE_CODE (base1) == MEM_REF)
  	offset1 += mem_ref_offset (base1).low * BITS_PER_UNIT;