From: Mike Stump <mikestump@comcast.net>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>,
Jeff Law <law@redhat.com>,
gcc-patches@gcc.gnu.org
Subject: Re: [PATCH 1/2] simplify-rtx: The truncation of an IOR can have all bits set (PR81423)
Date: Wed, 26 Jul 2017 20:50:00 -0000 [thread overview]
Message-ID: <CEA355BF-8A43-4035-9F15-403FEBEBE7F6@comcast.net> (raw)
In-Reply-To: <20170725221057.GJ13471@gate.crashing.org>
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On Jul 25, 2017, at 3:10 PM, Segher Boessenkool <segher@kernel.crashing.org> wrote:
>
> On Tue, Jul 25, 2017 at 12:30:13PM +0100, Kyrill Tkachov wrote:
>> We sometimes use the __mode__ attribute to force certain sizes in C types.
>> For example: typedef int ditype __attribute__ ((mode (DI)));
>> Maybe you can do this to force the right sizes. I don't know if there are
>> any targets
>> that don't support DImode ops though :)
>
> DImode isn't necessarily the same size on all targets, a byte isn't
> always eight bits.
As a practical matter, presently a byte is always eight bits and a DI is always 8 bytes in gcc. :-)
Pretending otherwise is a fool's errand. We like to kid ourselves that a character isn't always 8 bits, but the first person to want to do that will discover the lie it is.
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prev parent reply other threads:[~2017-07-26 20:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-18 19:36 Segher Boessenkool
2017-07-18 19:36 ` [PATCH 2/2] combine: Fix for PR81423 Segher Boessenkool
2017-07-19 6:19 ` [PATCH 1/2] simplify-rtx: The truncation of an IOR can have all bits set (PR81423) Jeff Law
2017-07-19 19:03 ` Segher Boessenkool
2017-07-24 8:56 ` Segher Boessenkool
2017-07-24 22:06 ` Jeff Law
2017-07-25 11:25 ` Segher Boessenkool
2017-08-07 22:33 ` Segher Boessenkool
2017-08-08 16:27 ` Jeff Law
2017-07-25 11:31 ` Kyrill Tkachov
2017-07-25 22:11 ` Segher Boessenkool
2017-07-26 20:50 ` Mike Stump [this message]
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