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Re: [PATCH 2/4] AArch64: Fix cost for Q register moves
- From: Marcus Shawcroft <marcus dot shawcroft at gmail dot com>
- To: Wilco Dijkstra <wdijkstr at arm dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 4 Sep 2014 16:53:31 +0100
- Subject: Re: [PATCH 2/4] AArch64: Fix cost for Q register moves
- Authentication-results: sourceware.org; auth=none
- References: <000d01cfc84e$d01c3eb0$7054bc10$ at com> <CAFqB+PwkyJ6nKZVqKne31XNE6FC72pnkvHwm5=UGbsD4nB+08Q at mail dot gmail dot com> <001001cfc856$c05e1e50$411a5af0$ at com>
On 4 September 2014 16:41, Wilco Dijkstra <wdijkstr@arm.com> wrote:
>> From: Marcus Shawcroft [mailto:marcus.shawcroft@gmail.com]
>> > - NAMED_PARAM (FP2FP, 4)
>> > + NAMED_PARAM (FP2FP, 2)
>>
>> This is not directly related to the change below and it is missing
>> from the ChangeLog. Originally this number had to be > 2 in order
>> for secondary reload to kick in. See the comment above the second
>> hunk of this patch. Why is it OK to lower this number ?
>
> It is related because the GET_MODE_SIZE bug means it never returns the
> correct cost, but instead returns the FP2FP cost. So the FP2FP cost had
> to be artificially increased. With the fix this is no longer required.
Yep, I read the code again, I understand. You still need to fix the
ChangeLog. OK to commit with a fixed ChangeLog.
Cheers
/Marcus