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Re: pa.md bugfix
- To: dave at hiauly1 dot hia dot nrc dot ca (John David Anglin)
- Subject: Re: pa.md bugfix
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- Date: Tue, 23 Jan 2001 11:32:06 -0500 (EST)
- Cc: gcc-patches at gcc dot gnu dot org, law at redhat dot com
> There is one issue and one potential optimisation that I can see with respect
> to this patch.
>
> > + ;; This can only be used in a leaf function, so we do
> > + ;; not need to use the PIC register.
> > (define_insn "return"
>
> This may not be correct. The ABI indicates that the PIC register must
> be correctly set when the function returns. This enables a correct return
> via a stub from a shared library. If +O3 is used, rename registers may
> use the PIC register if we don't have a use in the return. Remember,
> the PIC register is not a fixed register any more.
Hit self on head. It is fixed and as a result register rename won't
touch it.
--
J. David Anglin dave.anglin@nrc.ca
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)