[PATCH] Fix PR48098

[PATCH] Fix PR48098

[Richard Guenther]

I am currently testing the following patch for PR48098 which exposes
the fact that TREE_TYPE (vector-type) does not return T when
vector-type is built using make_vector_type (T).  This is because
we move all qualifiers from T to the vector-type and keep an unqualified
element type.  This finally confuses us with the requirement to
preserve conversions to restrict qualified pointers.

I need to think about this more.  For now make the check symmetric
(it's a bug that it wasn't) and compare unqualified types.  Any
issues this hides are missed optimizations with respect to restrict
handling.  It also eventually just postpones verification ICEs to
later phases.

Bootstrap and regtest running on x86_64-unknown-linux-gnu.

Richard.

2011-03-14  Richard Guenther  <rguenther@suse.de>

	PR middle-end/48098
	* tree.c (build_vector_from_val): Adjust assert to requirements
	and reality.

	* gcc.dg/torture/pr48098.c: New testcase.

Index: gcc/tree.c
===================================================================
*** gcc/tree.c	(revision 170933)
--- gcc/tree.c	(working copy)
*************** build_vector_from_val (tree vectype, tre
*** 1376,1383 ****
    if (sc == error_mark_node)
      return sc;
  
!   gcc_assert (useless_type_conversion_p (TREE_TYPE (sc),
! 					 TREE_TYPE (vectype)));
  
    v = VEC_alloc (constructor_elt, gc, nunits);
    for (i = 0; i < nunits; ++i)
--- 1376,1389 ----
    if (sc == error_mark_node)
      return sc;
  
!   /* Verify that the vector type is suitable for SC.  Note that there
!      is some inconsistency in the type-system with respect to restrict
!      qualifications of pointers.  Vector types always have a main-variant
!      element type and the qualification is applied to the vector-type.
!      So TREE_TYPE (vector-type) does not return a properly qualified
!      vector element-type.  */
!   gcc_checking_assert (types_compatible_p (TYPE_MAIN_VARIANT (TREE_TYPE (sc)),
! 					   TREE_TYPE (vectype)));
  
    v = VEC_alloc (constructor_elt, gc, nunits);
    for (i = 0; i < nunits; ++i)
Index: gcc/testsuite/gcc.dg/torture/pr48098.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr48098.c	(revision 0)
--- gcc/testsuite/gcc.dg/torture/pr48098.c	(revision 0)
***************
*** 0 ****
--- 1,12 ----
+ /* { dg-do compile } */
+ 
+ void
+ foo (int n)
+ {
+   static char *__restrict *p;
+   int i;
+   p = __builtin_malloc (n);
+   for (i = 0; i < n; i++)
+     p[i] = 0;
+ }
+