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| author | Szabolcs Nagy <nsz@port70.net> | 2013-05-15 23:08:52 +0000 |
|---|---|---|
| committer | Szabolcs Nagy <nsz@port70.net> | 2013-05-15 23:08:52 +0000 |
| commit | e216951f509b71da193da2fc63e25b998740d58b (patch) | |
| tree | 391381eafd8b0b7eb4fdbb693608072df5c181d5 /src/math/__tan.c | |
| parent | 2c184264eae3797de028403ed1e86c1f7ae5b813 (diff) | |
| download | musl-e216951f509b71da193da2fc63e25b998740d58b.tar.gz musl-e216951f509b71da193da2fc63e25b998740d58b.tar.bz2 musl-e216951f509b71da193da2fc63e25b998740d58b.tar.xz musl-e216951f509b71da193da2fc63e25b998740d58b.zip | |
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 'src/math/__tan.c')
| -rw-r--r-- | src/math/__tan.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/src/math/__tan.c b/src/math/__tan.c index 01e3fe48..fc739f95 100644 --- a/src/math/__tan.c +++ b/src/math/__tan.c @@ -65,7 +65,7 @@ pio4lo = 3.06161699786838301793e-17; /* 3C81A626, 33145C07 */ double __tan(double x, double y, int iy) { - double z, r, v, w, s, sign; + double_t z, r, v, w, s, sign; int32_t ix, hx; GET_HIGH_WORD(hx,x); @@ -106,7 +106,8 @@ double __tan(double x, double y, int iy) * -1.0 / (x+r) here */ /* compute -1.0 / (x+r) accurately */ - double a, t; + double_t a; + double z, t; z = w; SET_LOW_WORD(z,0); v = r - (z - x); /* z+v = r+x */ |