From: Jeff Law <law@redhat.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: "gcc-patches@gcc.gnu.org >> gcc-patches" <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH][PR target/15184] Fix for direct byte access on x86
Date: Fri, 30 Jan 2015 08:57:00 -0000 [thread overview]
Message-ID: <54CB1D43.8020406@redhat.com> (raw)
In-Reply-To: <20150129201331.GD28561@gate.crashing.org>
On 01/29/15 13:13, Segher Boessenkool wrote:
> On Thu, Jan 29, 2015 at 07:30:31AM -0700, Jeff Law wrote:
>> @@ -2643,6 +2644,34 @@ try_combine (rtx_insn *i3, rtx_insn *i2, rtx_insn *i1, rtx_insn *i0,
>> || GET_CODE (src) == LSHIFTRT)
>> nshift++;
>> }
>> +
>> + /* If I0 loads a memory and I3 sets the same memory, then I2 and I3
>> + are likely manipulating its value. Ideally we'll be able to combine
>> + all four insns into a bitfield insertion of some kind.
>
> "I1 and I2"?
>
> Very simple patch, nice :-)
Thanks. Fixed in the obvious way.
I'm also looking at 15596 which is in the same area that affects PPC. I
haven't come up with anything good for that one yet. But it feels like
it ought to have a similar flow (make_field_assignment creates some
interesting RTL, we choose an appropriate split point and the right
things should just happen).
Jeff
next prev parent reply other threads:[~2015-01-30 5:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-29 15:21 Jeff Law
2015-01-29 20:50 ` Segher Boessenkool
2015-01-30 8:57 ` Jeff Law [this message]
2015-01-29 15:51 Uros Bizjak
2015-01-29 16:06 ` Jakub Jelinek
2015-01-29 16:08 ` Uros Bizjak
2015-01-29 16:23 ` Jakub Jelinek
2015-01-29 21:42 ` H.J. Lu
2015-01-30 9:21 ` Jeff Law
2015-01-30 11:02 ` Uros Bizjak
2015-01-30 11:21 ` Jakub Jelinek
2015-01-30 11:21 ` Uros Bizjak
2015-01-30 11:46 ` Jakub Jelinek
2015-01-30 20:36 ` Jeff Law
2015-01-30 20:37 ` Jeff Law
2015-01-30 11:01 Dominique Dhumieres
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