From: Jakub Jelinek <jakub@redhat.com>
To: Bernd Schmidt <bernds@codesourcery.com>
Cc: Eric Botcazou <ebotcazou@adacore.com>,
Richard Sandiford <richard.sandiford@linaro.org>,
Richard Henderson <rth@redhat.com>,
GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: Add __builtin_clrsb, similar to clz/ctz
Date: Tue, 23 Aug 2011 10:25:00 -0000 [thread overview]
Message-ID: <20110823095243.GD2687@tyan-ft48-01.lab.bos.redhat.com> (raw)
In-Reply-To: <4E53744B.6040502@codesourcery.com>
On Tue, Aug 23, 2011 at 11:35:07AM +0200, Bernd Schmidt wrote:
> > cse_process_notes_1
> > perhaps could be changed for VOIDmode new_rtx to try to
> > simplify_replace_rtx it...
>
> Is this where the problem came from? Sounds like it's worth a try.
In this case, yes. But there are many other places all around the
compiler that need to disallow unary op with VOIDmode operand.
In cse.c alone e.g. fold_rtx (twice), in combine.c e.g. in do_SUBST,
subst, etc. Do we want to special case all those 7 unary ops there too?
Is it really worth it to save one subreg or truncate in the md patterns
for rarely used rtxes?
> Wasn't Richard S. working on a patch to give constants modes?
I don't think this is achievable for 4.7...
Jakub
next prev parent reply other threads:[~2011-08-23 9:53 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-16 13:06 Bernd Schmidt
2011-06-16 13:10 ` Georg-Johann Lay
2011-06-16 13:56 ` Laurent Desnogues
2011-06-16 13:59 ` Bernd Schmidt
2011-06-16 17:03 ` Richard Henderson
2011-06-20 20:32 ` Bernd Schmidt
2011-06-20 20:48 ` Richard Henderson
2011-06-21 16:39 ` [PATCH] Fix __bultin_clrsb* (PR middle-end/49489) Jakub Jelinek
2011-06-21 16:46 ` Bernd Schmidt
2011-06-23 6:23 ` Add __builtin_clrsb, similar to clz/ctz H.J. Lu
2011-07-12 3:50 ` Hans-Peter Nilsson
2011-08-23 10:07 ` Jakub Jelinek
2011-08-23 10:08 ` Bernd Schmidt
2011-08-23 10:19 ` Richard Guenther
2011-08-23 10:25 ` Jakub Jelinek [this message]
2011-08-23 10:34 ` Bernd Schmidt
2011-08-23 13:43 ` [PATCH] For FFS/CLZ/CTZ/CLRSB/POPCOUNT/PARITY/BSWAP require operand mode equal to operation mode (or VOIDmode) (PR middle-end/50161) Jakub Jelinek
2011-08-23 14:54 ` Georg-Johann Lay
2011-08-23 15:58 ` Jakub Jelinek
2011-08-23 16:16 ` Bernd Schmidt
2011-08-23 10:45 ` Add __builtin_clrsb, similar to clz/ctz Richard Sandiford
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