http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58034
--- Comment #6 from joseph at codesourcery dot com <joseph at codesourcery dot
com> ---
On Wed, 31 Jul 2013, amodra at gmail dot com wrote:
> The relevant test case source:
>
> if (setjmp (jmpbuf))
> {
> puts ("Exiting main...");
> return 0;
> }
>
> sprintf (p, "This should segv\n");
>
> return 1;
> }
>
> The sprintf is optimised to three loads and stores. The problem occurs due to
> the assignment of 1 to the REG holding the function return value being
> scheduled before the sprintf expansion.
Well, in valid code this sprintf can't trap (sprintf using glibc
extensions to register format extensions might). Optimizing to three
loads and stores, and then scheduling them, seems a valid optimization to
me. Does -fnon-call-exceptions help? (Though I'd prefer
-fno-builtin-sprintf as a fix for the glibc test.)
