[Bug inline-asm/68095] "cc" clobber with Flag Output Operands

[gccbugzilla at limegreensocks dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68095

--- Comment #6 from David <gccbugzilla at limegreensocks dot com> ---
Created attachment 37621
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37621&action=edit
Patch for missing clobber validations

I have created a patch (attached) that does the check I am describing.  And
while I was at it, I added a few other validations for clobber conditions.  The
patch includes testcases, but in short, these lines (which currently produce no
messages) would all give errors:

  __asm__ volatile("":::"eax","eax");
  __asm__ volatile("":::"memory", "memory");
  __asm__ volatile("":::"cc", "cc");
  __asm__ volatile("":"=@ccc"(c)::"cc");