[Bug middle-end/86680] possible gcc optimization
jakub at gcc dot gnu.org
gcc-bugzilla@gcc.gnu.org
Fri Jul 27 20:49:00 GMT 2018
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86680
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Yeah. You probably need something like:
void clear_bss1(void)
{
unsigned long *bss = __bss_start1;
asm ("" : "+g" (bss));
while (bss < __bss_end1)
*bss++ = 0UL;
}
to hide the UB from the optimizers; pointer arithmetics is only defined within
the same object and similarly pointer comparison other than ==/!=, while the
first function has two different objects.
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