This is the mail archive of the libc-alpha@sources.redhat.com mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH, i386]: Use missing gcc math builtins


Uros Bizjak wrote:
> This patch enhances libc's mathinline.h header to use some missing builtins
> (mainly rounding builtins) that were added during 4.0 timeframe.

But those builtins seem not to do much.  Just look at

#include <stdio.h>
int
main (void)
{
  double x = 4.5;
  printf ("%g\n", __builtin_exp2l (x));
  return 0;
}

The __builtin_exp2l call is not expanded inline, it's expanded to a call
to exp2l.  The definition in the libc header is complicated for a reason
and I don't think gcc wants to hardcode that.

I haven't looked at the remainder of the patch.  If there are some
builtins which are indeed useful and there is a difference in the code
generation, send a new patch.

-- 
â Ulrich Drepper â Red Hat, Inc. â 444 Castro St â Mountain View, CA â

Attachment: signature.asc
Description: OpenPGP digital signature


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]