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Re: New register allocator branch created
- To: Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>
- Subject: Re: New register allocator branch created
- From: Daniel Berlin <dberlin at redhat dot com>
- Date: Sun, 28 Jan 2001 14:12:25 -0500 (EST)
- cc: <dewar at gnat dot com>, <gcc at gcc dot gnu dot org>
On Sun, 28 Jan 2001, Richard Kenner wrote:
> Indeed, one has to react partly that the new allocator looks good, but
> partly also that the old one seems surprisingly bad in this case.
>
> My experience is that we do fairly well on machines with lots of registers,
> but quie poorly on machines with very few.
However, this example is on a powerpc, which has 77 hard registers (32
gpr, 32 floating).
That should have been plenty. I would imagine either the allocation order
is wrong or something, causing local/global-alloc to use a register it
shouldn't (the link register in this case), or it just felt it *had* to
use that register.
--dan