Help with define_insn and constraints

Richard Henderson rth@redhat.com
Thu Dec 23 23:10:00 GMT 2004


On Thu, Dec 23, 2004 at 04:37:40PM -0500, Ian Lance Taylor wrote:
> >  ?? In your first post, you said you had 19 hard regs.  Does this not imply
> > you're trying to keep your frame pointer in a pseudo ??
> 
> In gcc, it's normal for the frame pointer to be a pseudo which is
> eliminated to the stack pointer, or, in the case of a function which
> calls alloca, to be eliminated to some hard register which serves as
> the so-called hard frame pointer.  See FRAME_POINTER_REGNUM and
> HARD_FRAME_POINTER_REGNUM.

No.  The frame pointer is *never* a pseudo.  Sometimes a fake
hard register, but never a pseudo.


r~



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