From 8df4e219e43a4a257d0759b54fef8c488e2f282e Mon Sep 17 00:00:00 2001 From: Wilco Dijkstra Date: Fri, 18 Sep 2015 16:30:43 +0100 Subject: 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 [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. --- math/math.h | 42 ++++++++++++++++++++++++++++++++++-------- 1 file changed, 34 insertions(+), 8 deletions(-) (limited to 'math/math.h') 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 -- cgit 1.4.1