This is a regression present on the mainline and 4.8 branch and introduced by
the latest series of sizetype changes. Associated adjustments were made in
the various front-ends for it, most notably Ada which was the most affected,
but this issue slipped through the cracks in the form of a bogus overflow
detection for 0-based arrays with variable upper bound included in a record
with discriminant.
As suggested by Richard, we can use int_const_binop in lieu of size_binop when
we don't want overflow detection for sizetype in gigi.
Bootstrapped/regtested on x86_64-suse-linux, applied on mainline and branch.
2013-05-07 Eric Botcazou <ebotca...@adacore.com>
PR ada/56474
* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Array_Subtype>: Use
int_const_binop to shift bounds by 1 when they are integer constants.
2013-05-07 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/specs/array3.ads: New test.
--
Eric BotcazouIndex: gcc-interface/decl.c
===================================================================
--- gcc-interface/decl.c (revision 198517)
+++ gcc-interface/decl.c (working copy)
@@ -2447,15 +2447,17 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
gnu_orig_max,
gnu_orig_min),
gnu_min,
- size_binop (PLUS_EXPR, gnu_max,
- size_one_node));
+ int_const_binop (PLUS_EXPR, gnu_max,
+ size_one_node));
}
/* Finally we use (hb >= lb) ? hb : lb - 1 for the upper bound
in all the other cases. Note that, here as well as above,
the condition used in the comparison must be equivalent to
the condition (length != 0). This is relied upon in order
- to optimize array comparisons in compare_arrays. */
+ to optimize array comparisons in compare_arrays. Moreover
+ we use int_const_binop for the shift by 1 if the bound is
+ constant to avoid any unwanted overflow. */
else
gnu_high
= build_cond_expr (sizetype,
@@ -2464,8 +2466,11 @@ gnat_to_gnu_entity (Entity_Id gnat_entit
gnu_orig_max,
gnu_orig_min),
gnu_max,
- size_binop (MINUS_EXPR, gnu_min,
- size_one_node));
+ TREE_CODE (gnu_min) == INTEGER_CST
+ ? int_const_binop (MINUS_EXPR, gnu_min,
+ size_one_node)
+ : size_binop (MINUS_EXPR, gnu_min,
+ size_one_node));
/* Reuse the index type for the range type. Then make an index
type with the size range in sizetype. */
-- PR middle-end/56474
-- Reported by Pavel Zhukov <pa...@zhukoff.net>
-- { dg-do compile }
with Ada.Streams;
package Array3 is
use type Ada.Streams.Stream_Element_Offset;
type Vector (Size : Ada.Streams.Stream_Element_Offset) is record
Value : Ada.Streams.Stream_Element_Array (0 .. Size);
end record;
Empty_Vector : Vector (-1);
end Array3;
