This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: Patch to clean up uses of default_function_array_conversion
On Wed, 15 Jun 2005, Richard Guenther wrote:
> > A new version will need to be posted as it changes part of build_unary_op
> > I touched. I expect this new version will get rid of one of the remaining
> > outside-parser calls to default_function_array_conversion, which would be
> > good.
>
> Indeed. Updated patch and re-bootstrapped and regtested on
> i686-pc-linux-gnu (C language only).
>
> Ok for mainline?
This patch changes from having
TREE_SIDE_EFFECTS (adr) = 0; /* Default would be, same as EXP. */
only for addresses of variables to having it for all array-to-pointer
conversions. This is not safe, since the address of an array can have
side effects. For example, the following test (which should go in
gcc.c-torture/execute) passes before your patch but fails with it applied.
extern void abort (void);
extern void exit (int);
typedef __SIZE_TYPE__ size_t;
size_t a;
int b;
char c[2][2];
int
main (void)
{
a = ((size_t)-1)|(size_t)c[++b];
if (b != 1)
abort ();
exit (0);
}
--
Joseph S. Myers http://www.srcf.ucam.org/~jsm28/gcc/
jsm@polyomino.org.uk (personal mail)
joseph@codesourcery.com (CodeSourcery mail)
jsm28@gcc.gnu.org (Bugzilla assignments and CCs)