From: Jakub Jelinek <jakub@redhat.com>
To: Sebastian Pop <sebpop@gmail.com>
Cc: Richard Henderson <rth@redhat.com>,
gcc-patches@gcc.gnu.org, Uros Bizjak <ubizjak@gmail.com>
Subject: Re: PATCH: Add LWP support for upcoming AMD Orochi processor.
Date: Thu, 10 Dec 2009 21:01:00 -0000 [thread overview]
Message-ID: <20091210200641.GE22813@hs20-bc2-1.build.redhat.com> (raw)
In-Reply-To: <cb9d34b20912101142n7f1d0614i16ad991617d0bd1e@mail.gmail.com>
On Thu, Dec 10, 2009 at 01:42:41PM -0600, Sebastian Pop wrote:
> > 1) llwpcb* - the builtins are declared void __builtin_ia32_llwpcb* (void),
> > but lwpintrin.h expects them to take void * argument.
>
> Fixed.
>
> > If I understand right, the
> > insn in reality has 3 address sizes to support 16-bit/32-bit/64-bit code,
> > I fail to see why we'd need 3 different intrinsics, instead of just one and
> > one builtin that takes void * address and uses the insn matching Pmode.
>
> Unless I am doing something wrong, I remarked that the HI mode is not
> generated when I factor it in the :P mode. In the attached patch I
> merged only the 32 and 64 bit modes into one pattern for the llwpcb
> and slwpcb insns.
Why do you want the HI mode version generated, ever (except for 16-bit code which
gcc doesn't emit)? IMNSHO you don't want to ever use even the 32-bit one
for -m64 code. I believe you want lwpintrin.h to provide one intrinsic,
not three, it takes a void * argument anyway in all 3 cases. What would be
an intrinsic that just uses some lower bits from the pointer good for?
Why should a user care whether the pointer is 32-bit or 64-bit or 16-bit?
What could make some very limited sense is when that void * pointer is
initialized through say movl symbol, %edx use the 32-bit insn even for -m64
code to save one byte, but 1) I doubt it is worth writing the peepholes
2) you don't want to let the user make this decision, instead you want the
compiler to decide (if at all). And 16-bit addresses aren't really useful
at all.
Jakub
next prev parent reply other threads:[~2009-12-10 20:06 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-09 1:13 Harsha Jagasia
2009-10-09 10:07 ` Jakub Jelinek
2009-10-22 21:07 ` rajagopal, dwarak
2009-11-05 9:32 ` Jakub Jelinek
2009-11-05 16:21 ` Jakub Jelinek
2009-11-05 16:58 ` Sebastian Pop
2009-11-05 17:03 ` Richard Guenther
2009-11-05 17:21 ` Uros Bizjak
2009-11-06 10:15 ` Jakub Jelinek
2009-12-10 19:58 ` Sebastian Pop
2009-12-10 21:01 ` Jakub Jelinek [this message]
2009-12-10 21:04 ` Sebastian Pop
2009-12-10 21:52 ` Jakub Jelinek
2009-12-11 14:51 ` Jakub Jelinek
2009-12-11 16:54 ` Richard Henderson
2009-12-11 21:00 ` Sebastian Pop
2009-12-11 21:43 ` Jakub Jelinek
2009-12-11 22:27 ` Sebastian Pop
2009-12-12 9:27 ` Sebastian Pop
2009-12-14 16:35 ` Richard Henderson
2009-12-14 19:15 ` H.J. Lu
2009-12-14 19:21 ` Jakub Jelinek
2009-12-14 19:38 ` Richard Henderson
2009-12-14 20:15 ` Jakub Jelinek
2009-12-14 20:14 ` Uros Bizjak
2009-12-14 20:38 ` Jakub Jelinek
2009-12-14 20:52 ` Uros Bizjak
-- strict thread matches above, loose matches on Subject: below --
2009-10-09 2:12 Ross Ridge
2009-10-01 7:51 Uros Bizjak
2009-10-01 10:09 ` Jan Hubicka
2009-10-01 4:06 Harsha Jagasia
2009-10-01 6:30 ` Jakub Jelinek
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