[PR target/16888] clear reg names of unavailable regs

[James E Wilson]

Alexandre Oliva wrote:
> 	PR target/16888
> 	* config/i386/i386.h (CONDITIONAL_REGISTER_USAGE): Clear reg names
> 	for unavailable registers.

OK everywhere.  And the testcase too.

I was going to suggest that the patch was wrong, because you don't 
handle ADDITIONAL_REGISTER_NAMES, then I realized that macro is broken. 
  It has incorrect obsolete register numbers for the mmx registers.  It 
looks like the mmx registers overlayed stack registers when this code 
was originally developed, and then switched to be separate registers 
before the patch was contributed.  There were two vestiges of the 
orignal support left when contributed, MMX_REGISTER_NAMES which died in 
Jun 2001, and the ADDITIONAL_REGISTER_NAMES support which is still 
there.  This is harmless, because we always check register_names first, 
so the entries in ADDITIONAL_REGISTER_NAMES will never be used.  Still, 
it should be cleaned up.

And I see the HI_REGISTER_NAMES comment is missing some punctuation.

I had to stop looking at the sources so I wouldn't find any more bugs. 
I should probably fix these trivial errors myself.
-- 
Jim Wilson, GNU Tools Support, http://www.SpecifixInc.com