[Bug preprocessor/95782] New: [ppc64le] ICE in _cpp_pop_context

[evan@coeus-group.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95782

            Bug ID: 95782
           Summary: [ppc64le] ICE in _cpp_pop_context
           Product: gcc
           Version: 10.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: preprocessor
          Assignee: unassigned at gcc dot gnu.org
          Reporter: evan@coeus-group.com
  Target Milestone: ---

I'm running into an ICE on ppc64le:

  internal compiler error: in _cpp_pop_context, at libcpp/macro.c:2644

Here is a reproducer:

  #define a
  #define b(d) d
  #if defined(a)  
  b(vector double)
  #endif

Just running `gcc -E test.c` when targeting ppc64le triggers the issue.  It
happens with at least GCC 9 and 10.