https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106698
Bug ID: 106698
Summary: `-O2 -flto` cause linker warning
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: ada
Assignee: unassigned at gcc dot gnu.org
Reporter: jesper.quorning at gmail dot com
Target Milestone: ---
Created attachment 53484
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53484&action=edit
Minimal reproducer
Building `program.ada` with optimisation -O2 or above:
% gnatmake -O2 -flto main.adb
Causes linker warning:
```
gcc -c -O2 -flto main.adb
gcc -c -O2 -flto test.adb
gnatbind -x main.ali
gnatlink main.ali -O2 -flto
test.adb: In function 'test__assign':
test.adb:6:21: warning: writing 1 byte into a region of size 0
[-Wstringop-overflow=]
6 | The_Array (1) := AAAAA_Enum;
| ^
test.ads:11:4: note: at offset -9223372036854775808 into destination object 'F'
of size 4
11 | The_Array : T_Array;
| ^
```
The program is essentially:
type First_Enum is (AAAAA_Enum);
subtype Second_Enum is First_Enum;
type T_Array is array (Integer range -1 .. 2) of Second_Enum;
-- Change 'First to something >= 0 and the warning disappears.
-- Using the First_Enum instead of Second_Enum and the warning disappears.
GNATMAKE 12.1.0 - cause warning
GNATMAKE 11.2.0 - cause warning
GNATMAKE 10.3.0 - cause no warning
