https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106757
Peter Bergner <bergner at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |bergner at gcc dot gnu.org
--- Comment #3 from Peter Bergner <bergner at gcc dot gnu.org> ---
Is this the same bug, so just a simpler test case?
bergner@fowler:LTC193379$ cat bug.c
int len = 16;
extern char *src;
char dst[16];
void
foo (void)
{
#ifdef OK
for (int i = 0; i < 16; i++)
#else
for (int i = 0; i < len; i++)
#endif
dst[i] = src[i];
}
bergner@fowler:LTC193379$
/home/bergner/gcc/build/gcc-fsf-mainline-ltc193379-debug/gcc/xgcc
-B/home/bergner/gcc/build/gcc-fsf-mainline-ltc193379-debug/gcc -S -O3 -DOK
-ftree-vectorize bug.c
bergner@fowler:LTC193379$
/home/bergner/gcc/build/gcc-fsf-mainline-ltc193379-debug/gcc/xgcc
-B/home/bergner/gcc/build/gcc-fsf-mainline-ltc193379-debug/gcc -S -O3 -UOK
-fno-tree-vectorize bug.c
bergner@fowler:LTC193379$
/home/bergner/gcc/build/gcc-fsf-mainline-ltc193379-debug/gcc/xgcc
-B/home/bergner/gcc/build/gcc-fsf-mainline-ltc193379-debug/gcc -S -O3 -UOK
-ftree-vectorize bug.c
bug.c: In function ‘foo’:
bug.c:13:12: warning: writing 1 byte into a region of size 0
[-Wstringop-overflow=]
13 | dst[i] = src[i];
| ~~~~~~~^~~~~~~~
bug.c:3:6: note: at offset 16 into destination object ‘dst’ of size 16
3 | char dst[16];
| ^~~
bug.c:13:12: warning: writing 1 byte into a region of size 0
[-Wstringop-overflow=]
13 | dst[i] = src[i];
| ~~~~~~~^~~~~~~~
bug.c:3:6: note: at offset 17 into destination object ‘dst’ of size 16
3 | char dst[16];
| ^~~
I'll note that -fno-unroll-loops doesn't affect anything.
