From: Kyrill Tkachov <kyrylo.tkachov@foss.arm.com>
To: Ramana Radhakrishnan <ramana.gcc@googlemail.com>,
Christophe Lyon <christophe.lyon@linaro.org>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>,
Ramana Radhakrishnan <ramana.radhakrishnan@arm.com>,
Richard Earnshaw <Richard.Earnshaw@arm.com>,
Jim Wilson <jim.wilson@linaro.org>
Subject: Re: [PATCH][ARM][2/4] Fix operand costing logic for SMUL[TB][TB]
Date: Mon, 29 Feb 2016 12:18:00 -0000 [thread overview]
Message-ID: <56D43706.2060000@foss.arm.com> (raw)
In-Reply-To: <CAJA7tRZxUMrxzMwZnyD2zgt1Z1XZGL5t+7jbDuZnUALxaYJZvw@mail.gmail.com>
On 04/02/16 09:00, Ramana Radhakrishnan wrote:
> On Fri, Jan 22, 2016 at 9:52 AM, Kyrill Tkachov
> <kyrylo.tkachov@foss.arm.com> wrote:
>> Hi all,
>>
>> As part of investigating the codegen effects of a fix for PR 65932 I found
>> we assign
>> too high a cost for the sign-extending multiply instruction SMULBB.
>> This is because we add the cost of a multiply-extend but then also recurse
>> into the
>> SIGN_EXTEND sub-expressions rather than the registers (or subregs) being
>> sign-extended.
>>
>> This patch is a simple fix. The fix is right by itself, but in combination
>> with patch 3
>> fix the gcc.target/arm/wmul-2.c testcase.
>>
>> Bootstrapped and tested on arm-none-linux-gnueabihf.
>>
>> Ok for trunk?
>>
> OK.
Is it ok to backport this to the GCC 5 branch?
It fixes a testcase with cortex-a5 tuning and was tested by Christophe:
https://gcc.gnu.org/ml/gcc-patches/2016-02/msg01238.html
Thanks,
Kyrill
> Thanks,
> Ramana
>> Thanks,
>> Kyrill
>>
>> 2016-01-22 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
>>
>> * config/arm/arm.c (arm_new_rtx_costs, MULT case): Properly extract
>> the operands of the SIGN_EXTENDs from a SMUL[TB][TB] rtx.
next prev parent reply other threads:[~2016-02-29 12:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 9:52 Kyrill Tkachov
2016-02-04 9:00 ` Ramana Radhakrishnan
2016-02-29 12:18 ` Kyrill Tkachov [this message]
2016-02-03 8:32 Nick Clifton
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