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Disconnect the "optimized" asm variants of cos(), sin() and tan() from

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the build on i386.  Leave them in the source tree for regression tests.

The asm functions were always much less accurate (by a factor of more
than 10**18 in the worst case).  They were faster on old CPUs.  But
with each new generation of CPUs they get relatively slower.  The
double precision C version's average advantage is about a factor of 2
on Haswell.

The asm functions were already intentionally avoided in float and long
double precision on i386 and in all precisions on amd64.  Float
precision and amd64 give larger advantages to the C version.  The long
double precision C code and compilers' understanding of long double
precision are not so good, so the i387 is still slightly faster for
long double precision, except for the unimportant subcase of huge args
where the sub-optimal C code now somehow beats the i387 by about a
factor of 2.
This commit is contained in:
Bruce Evans 2016-09-04 14:12:19 +00:00
parent 1c1c35c74e
commit 5432c3bec3
1 changed files with 2 additions and 2 deletions
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4
lib/msun/i387/Makefile.inc
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@ -2,8 +2,8 @@
ARCH_SRCS = e_exp.S e_fmod.S e_log.S e_log10.S \
e_remainder.S e_sqrt.S s_ceil.S s_copysign.S \
s_cos.S s_finite.S s_floor.S s_llrint.S s_logb.S s_lrint.S \
s_remquo.S s_rint.S s_scalbn.S s_significand.S s_sin.S s_tan.S \
s_finite.S s_floor.S s_llrint.S s_logb.S s_lrint.S \
s_remquo.S s_rint.S s_scalbn.S s_significand.S \
s_trunc.S
# float counterparts