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Re: RFC -- update_equiv_regs and friends
- To: rth at redhat dot com
- Subject: Re: RFC -- update_equiv_regs and friends
- From: John Wehle <john at feith dot com>
- Date: Thu, 1 Mar 2001 21:49:44 -0500 (EST)
- Cc: amylaar at redhat dot com, law at redhat dot com, gcc at gcc dot gnu dot org
> On Fri, Mar 02, 2001 at 02:36:08AM +0000, Joern Rennecke wrote:
> > > 2) Change update_equiv_regs so it doesn't promote a REG_EQUAL note
> > > to a REG_EQUIV if there's a register mentioned.
> >
> > Promoting REG_EQUAL to REG_EQUIV is an important optimization for some
> > procesors for sums involving the stack pointer, the frame pointer,
> > virtual_stack_var_rtx and the argument pointer.
>
> I think he meant "pseudo register mentioned", which is what
> Jeff had being talking about.
You're very kind. :-) Actually I was taking the viewpoint that
promoting a REG_EQUAL which mentions hard registers (other than
FIXED_REGISTERs) will probably have the same reload problem that
Jeff mentioned.
-- John
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