[patch] Fix failure of ACATS c52102c

[Eric Botcazou]

Hi,

this test started to fail very recently on 32-bit platforms with 64-bit HWI.
Not sure exactly why, but the issue is straightforward and was latent.

For the following reference, a call to ao_ref_init_from_ptr_and_size yields:

(gdb) p debug_generic_expr((tree_node *) 0x7ffff6e01200)
&a[0 ...]{lb: 4294967292 sz: 4}
(gdb) p debug_generic_expr(size)
20
(gdb) p dref
$36 = {ref = 0x0, base = 0x7ffff6dfd260, offset = -137438953344, size = 160, 
  max_size = 160, ref_alias_set = 0, base_alias_set = 0, volatile_p = false}

The offset is bogus.  'a' is an array with lower bound -4 so {lb: 4294967292 
sz: 4} is actually {lb: -4 sz: 4}.  The computation of the offset goes wrong 
in get_addr_base_and_unit_offset_1 because it is not done in sizetype.

Fixed by copying the relevant bits from get_ref_base_and_extent, where the 
computation is correctly done in sizetype.

Tested on x86_64-suse-linux, OK for the mainline?


2013-11-30  Eric Botcazou  <ebotca...@adacore.com>

        * tree-dfa.h (get_addr_base_and_unit_offset_1) <case ARRAY_REF>: Do the
        offset computation using the precision of the index type.


2013-11-30  Eric Botcazou  <ebotca...@adacore.com>

        * gnat.dg/opt30.adb: New test.


-- 
Eric Botcazou
Index: tree-dfa.h
===================================================================
--- tree-dfa.h	(revision 205547)
+++ tree-dfa.h	(working copy)
@@ -102,11 +102,11 @@ get_addr_base_and_unit_offset_1 (tree ex
 		&& (unit_size = array_ref_element_size (exp),
 		    TREE_CODE (unit_size) == INTEGER_CST))
 	      {
-		HOST_WIDE_INT hindex = TREE_INT_CST_LOW (index);
-
-		hindex -= TREE_INT_CST_LOW (low_bound);
-		hindex *= TREE_INT_CST_LOW (unit_size);
-		byte_offset += hindex;
+		double_int doffset
+		  = (TREE_INT_CST (index) - TREE_INT_CST (low_bound))
+		    .sext (TYPE_PRECISION (TREE_TYPE (index)));
+		doffset *= tree_to_double_int (unit_size);
+		byte_offset += doffset.to_shwi ();
 	      }
 	    else
 	      return NULL_TREE;

-- { dg-do run }
-- { dg-options "-O" }

procedure Opt30 is

   function Id_I (I : Integer) return Integer is
   begin
      return I;
   end;

   A : array (Integer range -4..4) of Integer;

begin
   A := (-ID_I(4), -ID_I(3), -ID_I(2), -ID_I(1), ID_I(100),
          ID_I(1), ID_I(2), ID_I(3), ID_I(4));
   A(-4..0) := A(0..4);
   if A /= (100, 1, 2, 3, 4, 1, 2, 3, 4) then
      raise Program_Error;
   end if;
end;