From: "Michael P. Hayes" <michaelh@ongaonga.chch.cri.nz>
To: law@cygnus.com
Cc: "Michael P. Hayes" <michaelh@ongaonga.chch.cri.nz>,
gcc2@cygnus.com, egcs@cygnus.com
Subject: Re: Jump optimisation patches
Date: Mon, 02 Feb 1998 15:13:00 -0000 [thread overview]
Message-ID: <199802022109.KAA10442@ongaonga.chch.cri.nz> (raw)
In-Reply-To: <29444.886441074@hurl.cygnus.com>
Jeffrey A Law writes:
> Don't you also need one in the conditional for this optimization:
>
> /* If branches are expensive, convert
> if (foo) bar++; to bar += (foo != 0);
> and similarly for "bar--;"
>
I don't think so. It appears that this optimisation is caught
by the more general test (circa line 1000 in jump.c) for targets
that don't have CC0. The patches I submitted were to fix a problem
for those targets where an insn was moved into a place where
it clobbered something required by the following insn (usually
the contents of the CC register).
prev parent reply other threads:[~1998-02-02 15:13 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <199711050316.QAA19266@ongaonga.chch.cri.nz>
1998-02-02 1:09 ` Jeffrey A Law
1998-02-02 11:43 ` Michael P. Hayes
1998-02-02 10:32 ` Jeffrey A Law
1998-02-02 15:13 ` Michael P. Hayes [this message]
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