glibc/glibc-upstream-2.39-165.patch

44 lines
1.5 KiB
Diff

commit dd8c0c3bbd4e22e00a7275c75dc0d40f24bb0d68
Author: Wilco Dijkstra <wilco.dijkstra@arm.com>
Date: Fri Dec 13 15:43:07 2024 +0000
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. Exp10 is improved by moving invlog10_2N later
so that neglog10_2hiN and neglog10_2loN can be loaded using load-pair.
The exp benchmark improves 2.5%, "144bits" by 7.2%, "768bits" by 12.7% on
Neoverse V2. Exp10 improves by 1.5%.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit 5afaf99edb326fd9f36eb306a828d129a3a1d7f7)
diff --git a/sysdeps/ieee754/dbl-64/math_config.h b/sysdeps/ieee754/dbl-64/math_config.h
index ef87cfa6be9860e3..05515fd95ad15d52 100644
--- a/sysdeps/ieee754/dbl-64/math_config.h
+++ b/sysdeps/ieee754/dbl-64/math_config.h
@@ -195,16 +195,18 @@ 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];
- double invlog10_2N;
+
double neglog10_2hiN;
double neglog10_2loN;
double exp10_poly[5];
+ double invlog10_2N;
uint64_t tab[2*(1 << EXP_TABLE_BITS)];
} __exp_data attribute_hidden;