[Bug fortran/80965] [7/8 Regression] ICE with class argument and -O2 optimization

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80965

--- Comment #4 from Paul Thomas <pault at gcc dot gnu.org> ---
Created attachment 41519
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41519&action=edit
Patch for the bug

This appears to be a consequence of r241450, which fixed PR69834 (select type
clashes).

The fix depended on selection of the address of the selector vtable, which I
obtained using the intrinsic LOC function. In building the function call, I
used the name 'loc' for the symtree, which meant that all references to the
class object 'loc' picked up the intrinsic function. Changing the selecting
intrinsic name to '_loc' seems to fix the problem and all the select type
testcases regtest OK.

I am in the middle of working on a massive patch for PR34640 and so will come
back to this PR as soon as a I can.

Cheers

Paul