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Re: [AArch64] Emit division using the Newton series
- From: Evandro Menezes <e dot menezes at samsung dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Cc: James Greenhalgh <james dot greenhalgh at arm dot com>, Wilco Dijkstra <Wilco dot Dijkstra at arm dot com>, Andrew Pinski <pinskia at gmail dot com>
- Date: Wed, 23 Mar 2016 11:23:48 -0500
- Subject: Re: [AArch64] Emit division using the Newton series
- Authentication-results: sourceware.org; auth=none
- References: <56EB0EDF dot 3060401 at samsung dot com>
On 03/17/16 15:09, Evandro Menezes wrote:
This patch implements FP division by an approximation using the Newton
series.
With this patch, DF division is sped up by over 100% and SF division,
zilch, both on A57 and on M1.
gcc/
* config/aarch64/aarch64-tuning-flags.def
(AARCH64_EXTRA_TUNE_APPROX_DIV_{SF,DF}: New tuning macros.
* config/aarch64/aarch64-protos.h
(AARCH64_EXTRA_TUNE_APPROX_DIV): New macro.
(aarch64_emit_approx_div): Declare new function.
* config/aarch64/aarch64.c
(aarch64_emit_approx_div): Define new function.
* config/aarch64/aarch64.md ("div<mode>3"): New expansion.
* config/aarch64/aarch64-simd.md ("div<mode>3"): Likewise.
This version of the patch cleans up the changes to the MD files and
optimizes the division when the numerator is 1.0.
Again, I look forward to your feedback.
Thank you,
--
Evandro Menezes