[Bug c/116087] New: Add optional warning for too large macro expansion

[andi-gcc at firstfloor dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116087

            Bug ID: 116087
           Summary: Add optional warning for too large macro expansion
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
          Assignee: unassigned at gcc dot gnu.org
          Reporter: andi-gcc at firstfloor dot org
  Target Milestone: ---

The Linux kernel hit an interesting problem where a too complicated recursive
macro expansion caused significant compile time slow downs.

https://lore.kernel.org/lkml/1877ab0f14cf4f7d9da2a53e211cfdc1@AcuMS.aculab.com/T/

To catch such things easier it would be useful to have a optional warning that
warns when a macro expands to more text than a configurable size.