From: Rask Ingemann Lambertsen <rask@sygehus.dk>
To: Zack Weinberg <zack@codesourcery.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: Arch-independent double-word clz expansion and a few other tweaks for bitscanning
Date: Thu, 16 Aug 2007 10:36:00 -0000 [thread overview]
Message-ID: <20070816103548.GK25795@sygehus.dk> (raw)
In-Reply-To: <46BDF82E.80202@codesourcery.com>
On Sat, Aug 11, 2007 at 10:55:58AM -0700, Zack Weinberg wrote:
> I'm happy to change it around, but empirically, it doesn't seem to make
> any difference: initial RTL generation produces
>
> (insn 7 6 8 test.c:2 (parallel [
> (set (reg:CCZ 17 flags)
> (compare:CCZ (reg/v:DI 59 [ x ])
> (const_int 0 [0x0])))
> (set (reg:DI 61)
> (ctz:DI (reg/v:DI 59 [ x ])))
> ]) -1 (nil))
>
> despite that I wrote it the other way around in the insn pattern.
That's odd. But in any case, it only matters when combine tries find such
an instruction.
--
Rask Ingemann Lambertsen
next prev parent reply other threads:[~2007-08-16 10:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-11 6:45 Zack Weinberg
2007-08-11 9:06 ` Rask Ingemann Lambertsen
2007-08-11 11:05 ` Hans-Peter Nilsson
2007-08-11 13:23 ` Rask Ingemann Lambertsen
2007-08-11 18:42 ` Hans-Peter Nilsson
2007-08-11 20:38 ` Rask Ingemann Lambertsen
2007-08-12 1:08 ` Hans-Peter Nilsson
2007-08-15 19:05 ` Zack Weinberg
2007-08-16 0:01 ` Hans-Peter Nilsson
2007-08-11 13:48 ` Rask Ingemann Lambertsen
2007-08-11 14:28 ` Bernd Schmidt
2007-08-11 17:56 ` Zack Weinberg
2007-08-16 10:36 ` Rask Ingemann Lambertsen [this message]
2007-08-24 2:37 ` Mark Mitchell
2007-09-03 17:39 ` Zack Weinberg
2007-09-03 18:01 ` Mark Mitchell
2007-09-03 18:16 ` Zack Weinberg
2007-09-03 17:49 ` Zack Weinberg
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