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RE: [PATCH][AArch64] Make aarch64_min_divisions_for_recip_mul configurable
- From: "Wilco Dijkstra" <wdijkstr at arm dot com>
- To: "'GCC Patches'" <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 27 Apr 2015 14:43:05 +0100
- Subject: RE: [PATCH][AArch64] Make aarch64_min_divisions_for_recip_mul configurable
- Authentication-results: sourceware.org; auth=none
- References:
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> -----Original Message-----
> From: Wilco Dijkstra [mailto:wdijkstr@arm.com]
> Sent: 03 March 2015 18:06
> To: GCC Patches
> Subject: [PATCH][AArch64] Make aarch64_min_divisions_for_recip_mul configurable
>
> This patch makes aarch64_min_divisions_for_recip_mul configurable for float and double. This
> allows CPUs with really fast or multiple dividers to return 3 (or even 4) if that happens to
> be faster overall. No code generation change - bootstrap & regression OK.
>
> ChangeLog:
> 2015-03-03 Wilco Dijkstra <wdijkstr@arm.com>
>
> * gcc/config/aarch64/aarch64-protos.h (tune_params):
> Add min_div_recip_mul_sf and min_div_recip_mul_df fields.
> * gcc/config/aarch64/aarch64.c (aarch64_min_divisions_for_recip_mul):
> Return value depending on target.
> (generic_tunings): Initialize new target settings.
> (cortexa53_tunings): Likewise.
> (cortexa57_tunings): Likewise.
> (thunderx_tunings): Likewise.
> (xgene1_tunings): Likewise.
>
> ---
> gcc/config/aarch64/aarch64-protos.h | 2 ++
> gcc/config/aarch64/aarch64.c | 26 +++++++++++++++++++-------
> 2 files changed, 21 insertions(+), 7 deletions(-)
>
> diff --git a/gcc/config/aarch64/aarch64-protos.h b/gcc/config/aarch64/aarch64-protos.h
> index 59c5824..4331e5c 100644
> --- a/gcc/config/aarch64/aarch64-protos.h
> +++ b/gcc/config/aarch64/aarch64-protos.h
> @@ -177,6 +177,8 @@ struct tune_params
> const int int_reassoc_width;
> const int fp_reassoc_width;
> const int vec_reassoc_width;
> + const int min_div_recip_mul_sf;
> + const int min_div_recip_mul_df;
> };
>
> HOST_WIDE_INT aarch64_initial_elimination_offset (unsigned, unsigned);
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index e22d72e..42a96f6 100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -353,7 +353,9 @@ static const struct tune_params generic_tunings =
> 4, /* loop_align. */
> 2, /* int_reassoc_width. */
> 4, /* fp_reassoc_width. */
> - 1 /* vec_reassoc_width. */
> + 1, /* vec_reassoc_width. */
> + 2, /* min_div_recip_mul_sf. */
> + 2 /* min_div_recip_mul_df. */
> };
>
> static const struct tune_params cortexa53_tunings =
> @@ -371,7 +373,9 @@ static const struct tune_params cortexa53_tunings =
> 4, /* loop_align. */
> 2, /* int_reassoc_width. */
> 4, /* fp_reassoc_width. */
> - 1 /* vec_reassoc_width. */
> + 1, /* vec_reassoc_width. */
> + 2, /* min_div_recip_mul_sf. */
> + 2 /* min_div_recip_mul_df. */
> };
>
> static const struct tune_params cortexa57_tunings =
> @@ -389,7 +393,9 @@ static const struct tune_params cortexa57_tunings =
> 4, /* loop_align. */
> 2, /* int_reassoc_width. */
> 4, /* fp_reassoc_width. */
> - 1 /* vec_reassoc_width. */
> + 1, /* vec_reassoc_width. */
> + 2, /* min_div_recip_mul_sf. */
> + 2 /* min_div_recip_mul_df. */
> };
>
> static const struct tune_params thunderx_tunings =
> @@ -406,7 +412,9 @@ static const struct tune_params thunderx_tunings =
> 8, /* loop_align. */
> 2, /* int_reassoc_width. */
> 4, /* fp_reassoc_width. */
> - 1 /* vec_reassoc_width. */
> + 1, /* vec_reassoc_width. */
> + 2, /* min_div_recip_mul_sf. */
> + 2 /* min_div_recip_mul_df. */
> };
>
> static const struct tune_params xgene1_tunings =
> @@ -423,7 +431,9 @@ static const struct tune_params xgene1_tunings =
> 16, /* loop_align. */
> 2, /* int_reassoc_width. */
> 4, /* fp_reassoc_width. */
> - 1 /* vec_reassoc_width. */
> + 1, /* vec_reassoc_width. */
> + 2, /* min_div_recip_mul_sf. */
> + 2 /* min_div_recip_mul_df. */
> };
>
> /* A processor implementing AArch64. */
> @@ -512,9 +522,11 @@ static const char * const aarch64_condition_codes[] =
> };
>
> static unsigned int
> -aarch64_min_divisions_for_recip_mul (enum machine_mode mode ATTRIBUTE_UNUSED)
> +aarch64_min_divisions_for_recip_mul (enum machine_mode mode)
> {
> - return 2;
> + if (GET_MODE_UNIT_SIZE (mode) == 4)
> + return aarch64_tune_params->min_div_recip_mul_sf;
> + return aarch64_tune_params->min_div_recip_mul_df;
> }
>
> static int
> --
> 1.9.1