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Re: [PATCH][AArch64] vec_pack_trunc_<mode> should split after register allocator
- From: James Greenhalgh <james dot greenhalgh at arm dot com>
- To: "Hurugalawadi, Naveen" <Naveen dot Hurugalawadi at cavium dot com>
- Cc: "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, Marcus Shawcroft <marcus dot shawcroft at arm dot com>, <nd at arm dot com>
- Date: Fri, 21 Jul 2017 17:42:43 +0100
- Subject: Re: [PATCH][AArch64] vec_pack_trunc_<mode> should split after register allocator
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On Thu, Apr 27, 2017 at 05:08:38AM +0000, Hurugalawadi, Naveen wrote:
> Hi,
>
> The instruction "vec_pack_trunc_<mode>" should be split after register
> allocator for scheduling reasons. Currently the instruction is marked as type
> multiple which means it will scheduled as single issued. However, nothing can
> be scheduled with either xtn/xtn2 which is a problem in some cases.
What's the reason for splitting this only after reload? I think we can
split this whenever we like, and that there isn't any benefit in keeping
the pair together?
Am I missing something?
Thanks,
James
>
> The patch splits the instruction and fixes the issue.
>
> Please review the patch and let me know if its okay.
> Bootstrapped and Regression tested on aarch64-thunder-linux.
>
> 2017-04-27 Naveen H.S <Naveen.Hurugalawadi@cavium.com>
>
> * config/aarch64/aarch64-simd.md
> (aarch64_simd_vec_pack_trunc_hi_<mode>): New pattern.
> (vec_pack_trunc_<mode>): Split the instruction pattern.