[Bug target/113915] New: [14 regression] glibc miscompiled for armv7a since r14-4365-g0731889c026bfe

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113915

            Bug ID: 113915
           Summary: [14 regression] glibc miscompiled for armv7a since
                    r14-4365-g0731889c026bfe
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sjames at gcc dot gnu.org
                CC: ramana at gcc dot gnu.org, wilco at gcc dot gnu.org
  Target Milestone: ---

glibc seems to go from 30 failing innocent tests (*) to over 400 between gcc-13
and gcc-14. Bisected to r14-4365-g0731889c026bfe which fixed PR111235.

It's hard to know where to start with this. I'll try the usual bisection of
objects and then pragmas although I fear the (necessary) complexities of
glibc's build system may make my usual method tricky. We'll see...

I've bisected using glibc's posix/tst-getopt-cancel test as it had easy output
to grep for:
```
$ cat ./posix/tst-getopt-cancel.out
begin: no errors
Didn't expect signal from child: got `Segmentation fault'
```

(*) just from sandboxing stuff, they're normally not there and should be
unrelated given they happened w/ 13.