[PATCH] Fix PR46149

[Richard Guenther <rguenther at suse dot de>]

This fixes PR46149, we need to handle aggregate loads properly.

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

Richard.

2010-11-02  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/46149
	* tree-ssa-structalias.c (get_constraint_for_1): Properly handle
	non-indirect MEM_REF variants.

	* g++.dg/torture/pr46149.C: New testcase.

Index: gcc/testsuite/g++.dg/torture/pr46149.C
===================================================================
*** gcc/testsuite/g++.dg/torture/pr46149.C	(revision 0)
--- gcc/testsuite/g++.dg/torture/pr46149.C	(revision 0)
***************
*** 0 ****
--- 1,51 ----
+ // { dg-do run }
+ // { dg-options "-fno-tree-sra" }
+ 
+ struct S
+ {
+   S ():p ((char *) __builtin_calloc (1, 1))
+   {
+   }
+   char *p;
+ };
+ 
+ template < class T > struct A
+ {
+   A (const S & __m1, const T & __m2):m1 (__m1), m2 (__m2)
+   {
+   }
+   const S & m1;
+   const T & m2;
+ };
+ 
+ struct B:A < S >
+ {
+   B (const S & __v):A < S > (__v, __v)
+   {
+   }
+ };
+ 
+ struct C:A < B >
+ {
+   C (const S & __e1, const B & __e2):A < B > (__e1, __e2)
+   {
+   }
+ };
+ 
+ struct D
+ {
+   D (const C & __c):c (__c)
+   {
+   }
+   const C c;
+ };
+ 
+ int
+ main ()
+ {
+   S s;
+   B b (s);
+   C c (s, b);
+   D d (c);
+   return d.c.m2.m2.p[0];
+ }
Index: gcc/tree-ssa-structalias.c
===================================================================
*** gcc/tree-ssa-structalias.c	(revision 166172)
--- gcc/tree-ssa-structalias.c	(working copy)
*************** get_constraint_for_1 (tree t, VEC (ce_s,
*** 3339,3347 ****
--- 3339,3379 ----
  	  {
  	  case MEM_REF:
  	    {
+ 	      struct constraint_expr *c;
+ 	      varinfo_t vi, curr;
  	      tree off = double_int_to_tree (sizetype, mem_ref_offset (t));
  	      get_constraint_for_ptr_offset (TREE_OPERAND (t, 0), off, results);
  	      do_deref (results);
+ 
+ 	      /* If we are not taking the address then make sure to process
+ 		 all subvariables we might access.  */
+ 	      c = VEC_last (ce_s, *results);
+ 	      if (address_p
+ 		  || c->type != SCALAR)
+ 		return;
+ 
+ 	      vi = get_varinfo (c->var);
+ 	      curr = vi->next;
+ 	      if (!vi->is_full_var
+ 		  && curr)
+ 		{
+ 		  unsigned HOST_WIDE_INT size;
+ 		  if (host_integerp (TYPE_SIZE (TREE_TYPE (t)), 1))
+ 		    size = TREE_INT_CST_LOW (TYPE_SIZE (TREE_TYPE (t)));
+ 		  else
+ 		    size = -1;
+ 		  for (; curr; curr = curr->next)
+ 		    {
+ 		      if (curr->offset - vi->offset < size)
+ 			{
+ 			  struct constraint_expr cs = *c;
+ 			  cs.var = curr->id;
+ 			  VEC_safe_push (ce_s, heap, *results, &cs);
+ 			}
+ 		      else
+ 			break;
+ 		    }
+ 		}
  	      return;
  	    }
  	  case ARRAY_REF: