From d2febe7c407665c18cfea1930c65f41899ab3aa3 Mon Sep 17 00:00:00 2001
From: Wilco Dijkstra <wilco.dijkstra@arm.com>
Date: Fri, 13 Dec 2024 15:43:07 +0000
Subject: [PATCH] math: Improve layout of exp/exp10 data
GCC aligns global data to 16 bytes if their size is >= 16 bytes. This patch
changes the exp_data struct slightly so that the fields are better aligned
and without gaps. As a result on targets that support them, more load-pair
instructions are used in exp.
The exp benchmark improves 2.5%, "144bits" by 7.2%, "768bits" by 12.7% on
Neoverse V2.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 5afaf99edb326fd9f36eb306a828d129a3a1d7f7)
(cherry picked from commit 5a08d049dc5037e89eb95bb1506652f0043fa39e)
---
sysdeps/ieee754/dbl-64/math_config.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sysdeps/ieee754/dbl-64/math_config.h b/sysdeps/ieee754/dbl-64/math_config.h
index a346fdca58..6c6cee511f 100644
--- a/sysdeps/ieee754/dbl-64/math_config.h
+++ b/sysdeps/ieee754/dbl-64/math_config.h
@@ -134,10 +134,11 @@ check_uflow (double x)
extern const struct exp_data
{
double invln2N;
- double shift;
double negln2hiN;
double negln2loN;
double poly[4]; /* Last four coefficients. */
+ double shift;
+
double exp2_shift;
double exp2_poly[EXP2_POLY_ORDER];
uint64_t tab[2*(1 << EXP_TABLE_BITS)];