Hi,
the following bogus warning:
In function 'lto26',
inlined from 'main' at /home/eric/gnat/bugs/V721-018/b~lto26.adb:237:7:
lto26.adb:11:13: warning: writing 1 byte into a region of size 0 [-Wstringop-
overflow=]
11 | Set (R, (7, 0, 84, Stream_Element (I), 0, 0, 0), 1);
| ^
lto26.adb: In function 'main':
lto26.adb:11:50: note: at offset -9223372036854775808 into destination object
'A.0' of size 7
11 | Set (R, (7, 0, 84, Stream_Element (I), 0, 0, 0), 1);
| ^
comes from a discrepancy between get_offset_range, which uses a signed type,
and handle_array_ref, which uses an unsigned one, to do offset computations.
Tested on x86-64/Linux, OK for the mainline?
2022-08-16 Eric Botcazou <ebotca...@adacore.com>
* pointer-query.cc (handle_array_ref): Fix handling of low bound.
2022-08-16 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/lto26.adb: New test.
* gnat.dg/lto26_pkg1.ads, gnat.dg/lto26_pkg1.adb: New helper.
* gnat.dg/lto26_pkg2.ads, gnat.dg/lto26_pkg2.adb: Likewise.
--
Eric Botcazoudiff --git a/gcc/pointer-query.cc b/gcc/pointer-query.cc
index ae561731216..0f0100233c1 100644
--- a/gcc/pointer-query.cc
+++ b/gcc/pointer-query.cc
@@ -1796,14 +1796,19 @@ handle_array_ref (tree aref, gimple *stmt, bool addr, int ostype,
orng[0] = -orng[1] - 1;
}
- /* Convert the array index range determined above to a byte
- offset. */
+ /* Convert the array index range determined above to a byte offset. */
tree lowbnd = array_ref_low_bound (aref);
- if (!integer_zerop (lowbnd) && tree_fits_uhwi_p (lowbnd))
- {
- /* Adjust the index by the low bound of the array domain
- (normally zero but 1 in Fortran). */
- unsigned HOST_WIDE_INT lb = tree_to_uhwi (lowbnd);
+ if (TREE_CODE (lowbnd) == INTEGER_CST && !integer_zerop (lowbnd))
+ {
+ /* Adjust the index by the low bound of the array domain (0 in C/C++,
+ 1 in Fortran and anything in Ada) by applying the same processing
+ as in get_offset_range. */
+ const wide_int wlb = wi::to_wide (lowbnd);
+ signop sgn = SIGNED;
+ if (TYPE_UNSIGNED (TREE_TYPE (lowbnd))
+ && wlb.get_precision () < TYPE_PRECISION (sizetype))
+ sgn = UNSIGNED;
+ const offset_int lb = offset_int::from (wlb, sgn);
orng[0] -= lb;
orng[1] -= lb;
}
with Lto26_Pkg2; use Lto26_Pkg2;
package body Lto26_Pkg1 is
procedure Set (R : Rec; A : Stream_Element_Array; C :Unsigned_8) is
procedure My_Build is new Build;
begin
My_Build (A, C);
end;
end Lto26_Pkg1;
with Ada.Finalization;
with Ada.Streams; use Ada.Streams;
with Interfaces; use Interfaces;
package Lto26_Pkg1 is
type Rec is new Ada.Finalization.Limited_Controlled with null record;
procedure Set (R : Rec; A : Stream_Element_Array; C :Unsigned_8);
end Lto26_Pkg1;
with Ada.Streams; use Ada.Streams;
with Interfaces; use Interfaces;
package Lto26_Pkg2 is
generic
procedure Build (A : Stream_Element_Array; C : Unsigned_8);
end Lto26_Pkg2;
package body Lto26_Pkg2 is
procedure Build (A : Stream_Element_Array; C : Unsigned_8) is
Start : Stream_Element_Offset := A'First;
Next : Stream_Element_Offset;
Length : Unsigned_8;
begin
for I in 1 .. C loop
Length := Unsigned_8 (A (A'First));
Next := Start + Stream_Element_Offset (Length);
Start := Next;
end loop;
end;
end Lto26_Pkg2;
-- { dg-do run }
-- { dg-options "-O2 -flto" { target lto } }
with Ada.Streams; use Ada.Streams;
with Lto26_Pkg1; use Lto26_Pkg1;
procedure Lto26 is
R : Rec;
begin
for I in 1 .. 10 loop
Set (R, (7, 0, 84, Stream_Element (I), 0, 0, 0), 1);
end loop;
end;
