Re: cpp /usr/include/threads.h fails; modfl segfaults

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Aug 31 13:24, Brian Inglis wrote:
> On 2020-08-31 12:45, Corinna Vinschen wrote:
> > On Aug 31 09:37, Brian Inglis wrote:
> >> On 2020-08-31 01:35, Corinna Vinschen wrote:
> >>> On Aug 30 14:39, Brian Inglis wrote:
> >>>> On 2020-08-30 07:00, Corinna Vinschen wrote:
> >>>>> On Aug 29 08:52, airplanemath via Cygwin wrote:
> >>>>>> I have two reports.  A brief description of the system:
> >>>>>> $ uname -a | sed "s/${HOSTNAME}/\${HOSTNAME}/g"
> >>>>>> CYGWIN_NT-10.0 ${HOSTNAME} 3.1.7(0.340/5/3) 2020-08-22 17:48 x86_64 Cygwin
> >>>> ...
> >>>>>> $ cat test.c
> >>>>>> #include <math.h>
> >>>>>> #include <stdio.h>
> >>>>>> #include <stdlib.h>
> >>>>>>
> >>>>>> int main(int argc, char *argv[]) {
> >>>>>>   long double a, b, c;
> >>>>>>   char *num_end = NULL;
> >>>>>>   a = b = c = 0.0L;
> >>>>>>   if (argc != 2) {
> >>>>>>     fprintf(stderr, "Usage: %s NUMBER\n", argv[0]);
> >>>>>>     exit(1);
> >>>>>>   }
> >>>>>>   a = strtold(argv[1], &num_end);
> >>>>>>   b = modfl(a, &c);
> >>>>>>   printf("%Lf %Lf %Lf\n", a, b, c);
> >>>>>>   return 0;
> >>>>>> }
> >>>>>
> >>>>> This is a bug in the assembler code taken from Mingw-w64.  The bug has
> >>>>> been fixed upstream, so I just pulled in the upstream fixes.
> >>>>
> >>>> The 64 bit fix doesn't pop eax but *now* flags eax as clobbered, whereas the 32
> >>>> bit fix both pops and *now* flags eax as clobbered, which it really doesn't need
> >>>> to do. Is this inconsistent treatment correct?
> >>>
> >>> You may be right that this is not necessary on i686, but it doesn't
> >>> hurt either and I'd like to stick to the upstream code if possible.
> >>
> >> The upstream patch changed only amd64/x86_64 code sequences for multiple modules
> >> including modfl, and left i386/x86 untouched for those modules.
> 
> Just pointing out that they only modify their amd64/x86_64 code which doesn't
> push/pop rax/eax:

Where are you looking at?  As you could see from my output, I was
looking at the master branch of the upstream repo.

This lengthy discussion for a minor asm snippet doesn't make any sense.
If you think this is wrong, send patches to cygwin-patches and explain
where you got it from, preferrably as a git patch from the upstream
repo.


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer