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Re: [AArch64] Emit division using the Newton series


On 03/23/16 11:24, Evandro Menezes wrote:
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.

Ping^1

--
Evandro Menezes


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