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Re: [Patch AArch64] Set TARGET_OMIT_STRUCT_RETURN_REG to true.
- From: James Greenhalgh <james dot greenhalgh at arm dot com>
- To: Ramana Radhakrishnan <ramana dot radhakrishnan at foss dot arm dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, <nd at arm dot com>
- Date: Wed, 27 Apr 2016 15:06:11 +0100
- Subject: Re: [Patch AArch64] Set TARGET_OMIT_STRUCT_RETURN_REG to true.
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On Tue, Apr 26, 2016 at 02:22:58PM +0100, Ramana Radhakrishnan wrote:
> As $SUBJECT. The reason this caught my eye on aarch64 is because
> the return value register (x0) is not identical to the register in which
> the hidden parameter for AArch64 is set (x8). Thus setting this to true
> seems to be quite reasonable and shaves off 100 odd mov x0, x8's from
> cc1 in a bootstrap build.
>
> I don't expect this to make a huge impact on performance but as they say
> every little counts. The AAPCS64 is quite explicit about not requiring that
> the contents of x8 be kept live.
>
> Bootstrapped and regression tested on aarch64.
>
> Ok to apply ?
OK.
Thanks,
James