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From: Jakub Jelinek <jakub@redhat.com>
To: Richard Biener <richard.guenther@gmail.com>
Cc: Kugan <kugan.vivekanandarajah@linaro.org>,
	       "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH 2/2] Enable elimination of zext/sext
Date: Tue, 05 Aug 2014 14:21:00 -0000	[thread overview]
Message-ID: <20140805142142.GW7393@tucnak.redhat.com> (raw)
In-Reply-To: <CAFiYyc1Gh6teQWgc44j+U1w8S6oyXHigPj8N0-MqTOVg1Xbn5Q@mail.gmail.com>

On Tue, Aug 05, 2014 at 04:17:41PM +0200, Richard Biener wrote:
> what's the semantic of setting SRP_SIGNED_AND_UNSIGNED
> on the subreg?  That is, for the created (subreg:lhs_mode
> (reg:<PROMOTE_MODE of ssa> N))?

SRP_SIGNED_AND_UNSIGNED on a subreg should mean that
the subreg is both zero and sign extended, which means
that the topmost bit of the narrower mode is known to be zero,
and all bits above it in the wider mode are known to be zero too.
SRP_SIGNED means that the topmost bit of the narrower mode is
either 0 or 1 and depending on that the above wider mode bits
are either all 0 or all 1.
SRP_UNSIGNED means that regardless of the topmost bit value,
all above wider mode bits are 0.

	Jakub

  reply	other threads:[~2014-08-05 14:21 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-24 11:48 [PATCH 0/2] Zext/sext elimination using value range Kugan
2014-06-24 11:51 ` [PATCH 1/2] Enable setting sign and unsigned promoted mode (SPR_SIGNED_AND_UNSIGNED) Kugan
2014-06-24 12:18   ` Jakub Jelinek
2014-06-25  7:21     ` Kugan
2014-06-25  7:50       ` Jakub Jelinek
2014-06-26  1:06         ` Kugan
2014-06-26  2:48           ` Kugan
2014-06-26  5:50           ` Jakub Jelinek
2014-06-26  9:41             ` Kugan
2014-06-26 10:12               ` Jakub Jelinek
2014-06-26 10:42                 ` Jakub Jelinek
2014-07-01  8:21                 ` Kugan
2014-07-07  6:52                   ` Kugan
2014-07-07  8:06                     ` Jakub Jelinek
2014-06-26 10:25               ` Andreas Schwab
2014-07-01  8:28                 ` Kugan
2014-06-24 11:53 ` [PATCH 2/2] Enable elimination of zext/sext Kugan
2014-06-24 12:21   ` Jakub Jelinek
2014-06-25  8:15     ` Kugan
2014-06-25  8:36       ` Jakub Jelinek
2014-07-07  6:55         ` Kugan
2014-07-10 12:15           ` Richard Biener
2014-07-11 11:52             ` Kugan
2014-07-11 12:47               ` Richard Biener
2014-07-14  2:58                 ` Kugan
2014-07-14 20:11                   ` Bernhard Reutner-Fischer
2014-07-23 14:22                   ` Richard Biener
2014-08-01  4:51                     ` Kugan
2014-08-01 11:16                       ` Richard Biener
2014-08-01 16:04                         ` Kugan
2014-08-03 23:56                           ` Kugan
2014-08-05 14:18                           ` Richard Biener
2014-08-05 14:21                             ` Jakub Jelinek [this message]
2014-08-06 12:09                               ` Richard Biener
2014-08-06 13:22                                 ` Kugan
2014-08-06 13:29                                   ` Richard Biener
2014-08-07  5:25                                     ` Kugan
2014-08-07  8:09                                       ` Richard Biener
2014-08-27 10:01 Uros Bizjak
2014-08-27 10:07 ` Richard Biener
2014-08-27 10:32   ` Uros Bizjak
2014-08-27 10:32     ` Richard Biener
2014-09-01  8:48     ` Jakub Jelinek
2014-09-01  8:54       ` Uros Bizjak
2014-08-28  7:50   ` Kugan
2014-08-28  8:57     ` Richard Biener
2014-09-04  3:41       ` Kugan
2014-09-04 13:00         ` Richard Biener
2014-09-05  1:33           ` Kugan
2014-09-05  9:51             ` Richard Biener
2014-09-07  9:51               ` Kugan
2014-09-08  9:48                 ` Richard Biener
2014-09-09 10:06                   ` Kugan
2014-09-09 10:28                     ` Richard Biener
2014-08-27 13:02 ` Kugan
2014-08-28  3:46   ` Kugan
2014-08-28  6:44     ` Marc Glisse
2014-08-28  7:29       ` Kugan

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