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| author | Wilco Dijkstra <wdijkstr@arm.com> | 2015-09-18 16:30:43 +0100 |
|---|---|---|
| committer | Wilco Dijkstra <wdijkstr@arm.com> | 2015-09-18 16:34:45 +0100 |
| commit | 8df4e219e43a4a257d0759b54fef8c488e2f282e (patch) | |
| tree | fd17e1976bc8fb5443476300f9bcf9645de920a9 /math/math.h | |
| parent | cb2f668d4692df8d31b2ccf9b18b86bebe2d9174 (diff) | |
| download | glibc-8df4e219e43a4a257d0759b54fef8c488e2f282e.tar.gz | |
Add inlining of the C99 math functions isinf/isnan/signbit/isfinite/isnormal/fpclassify using GCC
built-ins when available. Since going through the PLT is expensive for these small functions,
inlining results in major speedups (about 7x on Cortex-A57 for isinf). The GCC built-ins are not
correct if signalling NaN support is required, and thus are turned off in that case (see GCC bug
66462). The test-snan.c tests sNaNs and so must be explicitly built with -fsignaling-nans.
2015-09-18 Wilco Dijkstra <wdijkstr@arm.com>
[BZ #15367]
[BZ #17441]
* math/Makefile: Build test-snan.c with -fsignaling-nans.
* math/math.h (fpclassify): Use __builtin_fpclassify when
available. (signbit): Use __builtin_signbit(f/l).
(isfinite): Use__builtin_isfinite. (isnormal): Use
__builtin_isnormal. (isnan): Use __builtin_isnan.
(isinf): Use __builtin_isinf_sign.
Diffstat (limited to 'math/math.h')
| -rw-r--r-- | math/math.h | 42 |
1 files changed, 34 insertions, 8 deletions
diff --git a/math/math.h b/math/math.h index 63511a68ec..fa476e0b34 100644 --- a/math/math.h +++ b/math/math.h @@ -225,8 +225,16 @@ enum FP_NORMAL }; +/* GCC bug 66462 means we cannot use the math builtins with -fsignaling-nan, + so disable builtins if this is enabled. When fixed in a newer GCC, + the __SUPPORT_SNAN__ check may be skipped for those versions. */ + /* Return number of classification appropriate for X. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ \ + && !defined __OPTIMIZE_SIZE__ +# define fpclassify(x) __builtin_fpclassify (FP_NAN, FP_INFINITE, \ + FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x) +# elif defined __NO_LONG_DOUBLE_MATH # define fpclassify(x) \ (sizeof (x) == sizeof (float) ? __fpclassifyf (x) : __fpclassify (x)) # else @@ -238,19 +246,29 @@ enum # endif /* Return nonzero value if sign of X is negative. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,0) # define signbit(x) \ - (sizeof (x) == sizeof (float) ? __signbitf (x) : __signbit (x)) + (sizeof (x) == sizeof (float) \ + ? __builtin_signbitf (x) \ + : sizeof (x) == sizeof (double) \ + ? __builtin_signbit (x) : __builtin_signbitl (x)) # else -# define signbit(x) \ +# ifdef __NO_LONG_DOUBLE_MATH +# define signbit(x) \ + (sizeof (x) == sizeof (float) ? __signbitf (x) : __signbit (x)) +# else +# define signbit(x) \ (sizeof (x) == sizeof (float) \ ? __signbitf (x) \ : sizeof (x) == sizeof (double) \ ? __signbit (x) : __signbitl (x)) +# endif # endif /* Return nonzero value if X is not +-Inf or NaN. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isfinite(x) __builtin_isfinite (x) +# elif defined __NO_LONG_DOUBLE_MATH # define isfinite(x) \ (sizeof (x) == sizeof (float) ? __finitef (x) : __finite (x)) # else @@ -262,11 +280,17 @@ enum # endif /* Return nonzero value if X is neither zero, subnormal, Inf, nor NaN. */ -# define isnormal(x) (fpclassify (x) == FP_NORMAL) +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isnormal(x) __builtin_isnormal (x) +# else +# define isnormal(x) (fpclassify (x) == FP_NORMAL) +# endif /* Return nonzero value if X is a NaN. We could use `fpclassify' but we already have this functions `__isnan' and it is faster. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isnan(x) __builtin_isnan (x) +# elif defined __NO_LONG_DOUBLE_MATH # define isnan(x) \ (sizeof (x) == sizeof (float) ? __isnanf (x) : __isnan (x)) # else @@ -278,7 +302,9 @@ enum # endif /* Return nonzero value if X is positive or negative infinity. */ -# ifdef __NO_LONG_DOUBLE_MATH +# if __GNUC_PREREQ (4,4) && !defined __SUPPORT_SNAN__ +# define isinf(x) __builtin_isinf_sign (x) +# elif defined __NO_LONG_DOUBLE_MATH # define isinf(x) \ (sizeof (x) == sizeof (float) ? __isinff (x) : __isinf (x)) # else |