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Re: [Qemu-devel] [PATCH v6 10/50] tcg: Avoid loops against variable boun
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH v6 10/50] tcg: Avoid loops against variable bounds |
Date: |
Tue, 17 Oct 2017 21:30:15 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 |
On 10/17/2017 03:03 PM, Emilio G. Cota wrote:
> On Mon, Oct 16, 2017 at 10:25:29 -0700, Richard Henderson wrote:
>> From: Richard Henderson <address@hidden>
>>
>> Copy s->nb_globals or s->nb_temps to a local variable for the purposes
>> of iteration. This should allow the compiler to use low-overhead
>> looping constructs on some hosts.
>>
>> Reviewed-by: Alex Bennée <address@hidden>
>> Signed-off-by: Richard Henderson <address@hidden>
>
> Reviewed-by: Emilio G. Cota <address@hidden>
>
> FWIW on a Skylake host I couldn't measure a difference. However, the
> generated code is indeed slightly different.
I wouldn't expect so. Low-overhead loops are more of a ppc thing.
r~
- [Qemu-devel] [PATCH v6 05/50] tcg: Introduce arg_temp, (continued)
- [Qemu-devel] [PATCH v6 05/50] tcg: Introduce arg_temp, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 06/50] tcg: Add temp_global bit to TCGTemp, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 07/50] tcg: Return NULL temp for TCG_CALL_DUMMY_ARG, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 08/50] tcg: Introduce temp_arg, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 10/50] tcg: Avoid loops against variable bounds, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 11/50] tcg: Change temp_allocate_frame arg to TCGTemp, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 12/50] tcg: Remove unused TCG_CALL_DUMMY_TCGV, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 09/50] tcg: Use per-temp state data in liveness, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 13/50] tcg: Export temp_idx, Richard Henderson, 2017/10/16
- [Qemu-devel] [PATCH v6 15/50] tcg: Push tcg_ctx into generator functions, Richard Henderson, 2017/10/16