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author | Szabolcs Nagy <nsz@port70.net> | 2013-05-15 23:08:52 +0000 |
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committer | Szabolcs Nagy <nsz@port70.net> | 2013-05-15 23:08:52 +0000 |
commit | e216951f509b71da193da2fc63e25b998740d58b (patch) | |
tree | 391381eafd8b0b7eb4fdbb693608072df5c181d5 /include/sys/poll.h | |
parent | 2c184264eae3797de028403ed1e86c1f7ae5b813 (diff) | |
download | musl-e216951f509b71da193da2fc63e25b998740d58b.tar.gz |
math: use double_t for temporaries to avoid stores on i386
When FLT_EVAL_METHOD!=0 (only i386 with x87 fp) the excess
precision of an expression must be removed in an assignment.
(gcc needs -fexcess-precision=standard or -std=c99 for this)
This is done by extra load/store instructions which adds code
bloat when lot of temporaries are used and it makes the result
less precise in many cases.
Using double_t and float_t avoids these issues on i386 and
it makes no difference on other archs.
For now only a few functions are modified where the excess
precision is clearly beneficial (mostly polynomial evaluations
with temporaries).
object size differences on i386, gcc-4.8:
old new
__cosdf.o 123 95
__cos.o 199 169
__sindf.o 131 95
__sin.o 225 203
__tandf.o 207 151
__tan.o 605 499
erff.o 1470 1416
erf.o 1703 1649
j0f.o 1779 1745
j0.o 2308 2274
j1f.o 1602 1568
j1.o 2286 2252
tgamma.o 1431 1424
math/*.o 64164 63635
Diffstat (limited to 'include/sys/poll.h')
0 files changed, 0 insertions, 0 deletions