Local update flow info assumes valid situations are illegal

[Alexandre Oliva]

On Jan  4, 2001, Richard Henderson <rth@redhat.com> wrote:

> On Thu, Jan 04, 2001 at 06:19:35PM -0200, Alexandre Oliva wrote:
>> [ live registers: ... B ... ]
>> (set (reg A) (reg B))
>> (set (reg C) (minus (reg A) (reg A))) REG_DEAD A
>> 
>> Note that there wasn't any REG_DEAD note for B in the first set, even
>> though B was indeed dead.  Does it make any difference the fact that B
>> is not a pseudo (even though it's not a real hardware register
>> either), but an must-be-eliminated fixed call-clobbered register?

> Hmm.  I know there are queer special cases for stack_pointer
> and frame_pointer and arg_pointer; I was not aware of any
> special cases for other fixed registers.

It happens to be the frame pointer, in this case.

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                  aoliva@{cygnus.com, redhat.com}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist    *Please* write to mailing lists, not to me