[Bug middle-end/108140] ICE expanding __rbit

["amonakov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108140

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |amonakov at gcc dot gnu.org
           Keywords|                            |ice-on-valid-code
          Component|c                           |middle-end
             Target|                            |aarch64-*-*
            Summary|tzcnt gives different       |ICE expanding __rbit
                   |result in debug vs release  |

--- Comment #4 from Alexander Monakov <amonakov at gcc dot gnu.org> ---
When comment #0 says "this crashes at -O2", it means ICE in expand for the
'__rbit' intrinsic on this testcase, which is reproducible on 12.2 and trunk:

#include<stdio.h>
#include<arm_acle.h>
int main(int argc, char *argv[])
{       
        unsigned long long input = argc-1;
        unsigned long long v = __clz(__rbit(input));
        printf("%d %d\n", argc, v >= 64 ? 123 : 456);
}

I've edited the bug title to reflect this.