[Bug c/81763] New: Issues with 32bit x86 apps on GCC 7.1+

[mike at fireburn dot co.uk]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81763

            Bug ID: 81763
           Summary: Issues with 32bit x86 apps on GCC 7.1+
           Product: gcc
           Version: 7.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mike at fireburn dot co.uk
  Target Milestone: ---

I've been seeing issues with 32bit x86 llvm & mesa when using GCC 7.1.0 and
I've just tested GCC 7.2 RC

When llvm & mesa are compiled with GCC 7.1.0+ and I run a 32bit glxgears it
segfaults, the 64bit version work fine and if I recompile with GCC 6.3.0
everything works fine too (games also segfault but glxgears is a nice cut down
example)

This is only with the radeonsi driver, i965 works fine

https://bugs.freedesktop.org/show_bug.cgi?id=101881

It would be nice to rule out a GCC issue before 7.2.0 is released, the last
time I tried turning on debugging the issue no longer manifested.

Is there anything you can think of that might help pinpoint the bug?