From: Jeffrey A Law <law@hurl.cygnus.com>
To: "Martin v. Loewis" <martin@mira.isdn.cs.tu-berlin.de>
Cc: hjl@varesearch.com, medtekh@orc.ru, egcs@egcs.cygnus.com
Subject: Re: gcc-2.7 creates faster code than pgcc-1.1.1
Date: Thu, 04 Mar 1999 18:08:00 -0000 [thread overview]
Message-ID: <13494.920599668@hurl.cygnus.com> (raw)
In-Reply-To: Your message of Fri, 05 Mar 1999 01:01:59 MST. < 199903050001.BAA00973@mira.isdn.cs.tu-berlin.de >
In message < 199903050001.BAA00973@mira.isdn.cs.tu-berlin.de >you write:
> > - if ((TARGET_ZERO_EXTEND_WITH_AND || REGNO (operands[0]) == 0)
> > + if ((TARGET_ZERO_EXTEND_WITH_AND || (0 & REGNO (operands[0]) == 0))
>
> It's late, so I'm probably going to say stupid things, but ...
>
> Isn't (0 & REGNO (operands[0]) == 0) always 0? Why isn't the condition
> just deleted?
Disabling the code like that is actually the wrong thing to do for certain
processor variants.
I need to dust off my changes to this code which do the right thing when
optimizing for size, PPro, Pent and older x86 variants.
It's not as simple as just deleting the test like that.
jeff
WARNING: multiple messages have this Message-ID
From: Jeffrey A Law <law@hurl.cygnus.com>
To: "Martin v. Loewis" <martin@mira.isdn.cs.tu-berlin.de>
Cc: hjl@varesearch.com, medtekh@orc.ru, egcs@egcs.cygnus.com
Subject: Re: gcc-2.7 creates faster code than pgcc-1.1.1
Date: Wed, 31 Mar 1999 23:46:00 -0000 [thread overview]
Message-ID: <13494.920599668@hurl.cygnus.com> (raw)
Message-ID: <19990331234600.yyNEIbP0nUBDNSZm2-e4Vipldrm6ub2vzwwf3RQEc8k@z> (raw)
In-Reply-To: <199903050001.BAA00973@mira.isdn.cs.tu-berlin.de>
In message < 199903050001.BAA00973@mira.isdn.cs.tu-berlin.de >you write:
> > - if ((TARGET_ZERO_EXTEND_WITH_AND || REGNO (operands[0]) == 0)
> > + if ((TARGET_ZERO_EXTEND_WITH_AND || (0 & REGNO (operands[0]) == 0))
>
> It's late, so I'm probably going to say stupid things, but ...
>
> Isn't (0 & REGNO (operands[0]) == 0) always 0? Why isn't the condition
> just deleted?
Disabling the code like that is actually the wrong thing to do for certain
processor variants.
I need to dust off my changes to this code which do the right thing when
optimizing for size, PPro, Pent and older x86 variants.
It's not as simple as just deleting the test like that.
jeff
next prev parent reply other threads:[~1999-03-04 18:08 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-03-04 14:31 H.J. Lu
[not found] ` < m10Igdx-000AUaC@shanghai.varesearch.com >
1999-03-04 16:04 ` Martin v. Loewis
[not found] ` < 199903050001.BAA00973@mira.isdn.cs.tu-berlin.de >
1999-03-04 16:46 ` H.J. Lu
[not found] ` < m10Iil3-000393C@ocean.lucon.org >
1999-03-04 17:03 ` Joe Buck
[not found] ` < 199903050102.RAA06944@atrus.synopsys.com >
1999-03-04 17:06 ` H.J. Lu
1999-03-31 23:46 ` H.J. Lu
1999-03-31 23:46 ` Joe Buck
1999-03-05 6:52 ` craig
[not found] ` < 19990305145306.4796.qmail@deer >
1999-03-05 9:18 ` Jeffrey A Law
1999-03-31 23:46 ` Jeffrey A Law
1999-03-31 23:46 ` craig
1999-03-31 23:46 ` H.J. Lu
1999-03-04 18:08 ` Jeffrey A Law [this message]
[not found] ` < 13494.920599668@hurl.cygnus.com >
1999-03-04 20:03 ` H.J. Lu
[not found] ` < m10Ilq3-00000YC@ocean.lucon.org >
1999-03-04 20:14 ` Jeffrey A Law
1999-03-31 23:46 ` Jeffrey A Law
1999-03-31 23:46 ` H.J. Lu
1999-03-31 23:46 ` Jeffrey A Law
1999-03-31 23:46 ` Martin v. Loewis
1999-03-31 23:46 ` H.J. Lu
-- strict thread matches above, loose matches on Subject: below --
1999-03-09 1:19 Òåðåõèà Âÿ÷åñëà â
1999-03-31 23:46 ` Òåðåõèà Âÿ÷åñëà â
1999-03-04 23:11 Терехин Вячеслав
[not found] ` < 005601be66d7$ae033480$288230d4@main.medtech.ru >
1999-03-05 9:22 ` Alfred Perlstein
[not found] ` < Pine.BSF.3.96.990305121935.7355C-100000@cygnus.rush.net >
1999-03-05 13:02 ` Richard Henderson
1999-03-31 23:46 ` Richard Henderson
1999-03-31 23:46 ` Alfred Perlstein
1999-03-05 15:52 ` H.J. Lu
1999-03-31 23:46 ` H.J. Lu
1999-03-31 23:46 ` Терехин Вячеслав
1999-03-04 3:40 Терехин Вячеслав
[not found] ` < 001401be6633$fed21a60$a18330d4@main.medtech.ru >
1999-03-04 13:20 ` Jamie Lokier
[not found] ` < 19990304222018.A21939@pcep-jamie.cern.ch >
1999-03-04 17:05 ` Zack Weinberg
[not found] ` < 199903050104.UAA15335@octiron.phys.columbia.edu >
1999-03-04 18:09 ` Jeffrey A Law
[not found] ` <law@hurl.cygnus.com>
[not found] ` < 13506.920599740@hurl.cygnus.com >
1999-03-04 20:04 ` David Edelsohn
[not found] ` < 9903050403.AA36338@marc.watson.ibm.com >
1999-03-04 20:31 ` Jeffrey A Law
[not found] ` < 13939.920608288@hurl.cygnus.com >
1999-03-05 6:53 ` craig
[not found] ` < 19990305143358.4747.qmail@deer >
1999-03-05 9:30 ` Jeffrey A Law
[not found] ` < 15755.920655014@hurl.cygnus.com >
1999-03-05 10:18 ` Joe Buck
1999-03-31 23:46 ` Joe Buck
1999-03-05 10:19 ` craig
1999-03-31 23:46 ` craig
1999-03-31 23:46 ` Jeffrey A Law
1999-03-31 23:46 ` craig
1999-03-31 23:46 ` Jeffrey A Law
1999-03-07 11:01 ` Zack Weinberg
1999-03-31 23:46 ` Zack Weinberg
1999-03-31 23:46 ` David Edelsohn
1999-03-31 23:46 ` Jeffrey A Law
1999-03-31 23:46 ` Zack Weinberg
1999-03-31 23:46 ` Jamie Lokier
1999-03-31 23:46 ` Терехин Вячеслав
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