[Bug c/90628] __builtin_mul_overflow writes to const qualified integer

[gcc.hall at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90628

--- Comment #2 from Jeremy <gcc.hall at gmail dot com> ---
(In reply to Marc Glisse from comment #1)
> Thanks for the report.
> (next time, please include a complete, compilable example, with the
> #includes, int main, etc)

Sorry, here is a complete program:-

#include <stdio.h>

int
main( int argc, const __attribute__ ((unused)) char *argv[] )
{
  const int a = argc;
  const int b = argc;

  if( __builtin_mul_overflow( a, b, &a ) )
        puts( "overflow" );

  printf( "square = %d\n", a );
}