4b6574a6f6
include/math.h has a mechanism to redirect internal calls to various libm functions, that can often be inlined by the compiler, to call non-exported __* names for those functions in the case when the calls aren't inlined, with the redirection being disabled when NO_MATH_REDIRECT. Add fma to the functions to which this mechanism is applied. At present, libm-internal fma calls (generally to __builtin_fma* functions) are only done when it's known the call will be inlined, with alternative code not relying on an fma operation being used in the caller otherwise. This patch is in preparation for adding the TS 18661 / C2X narrowing fma functions to glibc; it will be natural for the narrowing function implementations to call the underlying fma functions unconditionally, with this either being inlined or resulting in an __fma* call. (Using two levels of round-to-odd computation like that, in the case where there isn't an fma hardware instruction, isn't optimal but is certainly a lot simpler for the initial implementation than writing different narrowing fma implementations for all the various pairs of formats.) Tested with build-many-glibcs.py that installed stripped shared libraries are unchanged by the patch (using <https://sourceware.org/pipermail/libc-alpha/2021-September/130991.html> to fix installed library stripping in build-many-glibcs.py). Also tested for x86_64.
173 lines
4.8 KiB
C
173 lines
4.8 KiB
C
#ifndef _MATH_H
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#ifdef _ISOMAC
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# undef NO_LONG_DOUBLE
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#endif
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#include <math/math.h>
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#ifndef _ISOMAC
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/* Now define the internal interfaces. */
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extern int __signgam;
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# if IS_IN (libc) || IS_IN (libm)
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hidden_proto (__finite)
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hidden_proto (__isinf)
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hidden_proto (__isnan)
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hidden_proto (__finitef)
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hidden_proto (__isinff)
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hidden_proto (__isnanf)
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# if !defined __NO_LONG_DOUBLE_MATH \
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&& __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
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hidden_proto (__finitel)
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hidden_proto (__isinfl)
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hidden_proto (__isnanl)
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# endif
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# if __HAVE_DISTINCT_FLOAT128
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hidden_proto (__finitef128)
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hidden_proto (__isinff128)
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hidden_proto (__isnanf128)
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# endif
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# endif
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libm_hidden_proto (__fpclassify)
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libm_hidden_proto (__fpclassifyf)
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libm_hidden_proto (__issignaling)
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libm_hidden_proto (__issignalingf)
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libm_hidden_proto (__exp)
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libm_hidden_proto (__expf)
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# if !defined __NO_LONG_DOUBLE_MATH \
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&& __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 0
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libm_hidden_proto (__fpclassifyl)
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libm_hidden_proto (__issignalingl)
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libm_hidden_proto (__expl)
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libm_hidden_proto (__expm1l)
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# endif
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# if __HAVE_DISTINCT_FLOAT128
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libm_hidden_proto (__fpclassifyf128)
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libm_hidden_proto (__issignalingf128)
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libm_hidden_proto (__expf128)
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libm_hidden_proto (__expm1f128)
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# endif
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#include <stdint.h>
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#include <nan-high-order-bit.h>
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/* A union which permits us to convert between a float and a 32 bit
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int. */
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typedef union
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{
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float value;
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uint32_t word;
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} ieee_float_shape_type;
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/* Get a 32 bit int from a float. */
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#ifndef GET_FLOAT_WORD
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# define GET_FLOAT_WORD(i,d) \
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do { \
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ieee_float_shape_type gf_u; \
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gf_u.value = (d); \
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(i) = gf_u.word; \
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} while (0)
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#endif
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/* Set a float from a 32 bit int. */
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#ifndef SET_FLOAT_WORD
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# define SET_FLOAT_WORD(d,i) \
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do { \
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ieee_float_shape_type sf_u; \
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sf_u.word = (i); \
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(d) = sf_u.value; \
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} while (0)
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#endif
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extern inline int
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__issignalingf (float x)
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{
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uint32_t xi;
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GET_FLOAT_WORD (xi, x);
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#if HIGH_ORDER_BIT_IS_SET_FOR_SNAN
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/* We only have to care about the high-order bit of x's significand, because
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having it set (sNaN) already makes the significand different from that
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used to designate infinity. */
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return (xi & 0x7fc00000) == 0x7fc00000;
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#else
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/* To keep the following comparison simple, toggle the quiet/signaling bit,
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so that it is set for sNaNs. This is inverse to IEEE 754-2008 (as well as
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common practice for IEEE 754-1985). */
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xi ^= 0x00400000;
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/* We have to compare for greater (instead of greater or equal), because x's
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significand being all-zero designates infinity not NaN. */
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return (xi & 0x7fffffff) > 0x7fc00000;
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#endif
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}
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# if __HAVE_DISTINCT_FLOAT128
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/* __builtin_isinf_sign is broken in GCC < 7 for float128. */
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# if ! __GNUC_PREREQ (7, 0)
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# include <ieee754_float128.h>
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extern inline int
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__isinff128 (_Float128 x)
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{
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int64_t hx, lx;
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GET_FLOAT128_WORDS64 (hx, lx, x);
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lx |= (hx & 0x7fffffffffffffffLL) ^ 0x7fff000000000000LL;
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lx |= -lx;
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return ~(lx >> 63) & (hx >> 62);
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}
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# endif
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extern inline _Float128
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fabsf128 (_Float128 x)
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{
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return __builtin_fabsf128 (x);
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}
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# endif
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# if !(defined __FINITE_MATH_ONLY__ && __FINITE_MATH_ONLY__ > 0)
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# ifndef NO_MATH_REDIRECT
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/* Declare some functions for use within GLIBC. Compilers typically
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inline those functions as a single instruction. Use an asm to
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avoid use of PLTs if it doesn't. */
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# define MATH_REDIRECT(FUNC, PREFIX, ARGS) \
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float (FUNC ## f) (ARGS (float)) asm (PREFIX #FUNC "f"); \
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double (FUNC) (ARGS (double)) asm (PREFIX #FUNC ); \
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MATH_REDIRECT_LDBL (FUNC, PREFIX, ARGS) \
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MATH_REDIRECT_F128 (FUNC, PREFIX, ARGS)
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# if defined __NO_LONG_DOUBLE_MATH \
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|| __LDOUBLE_REDIRECTS_TO_FLOAT128_ABI == 1
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# define MATH_REDIRECT_LDBL(FUNC, PREFIX, ARGS)
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# else
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# define MATH_REDIRECT_LDBL(FUNC, PREFIX, ARGS) \
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long double (FUNC ## l) (ARGS (long double)) asm (PREFIX #FUNC "l");
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# endif
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# if __HAVE_DISTINCT_FLOAT128
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# define MATH_REDIRECT_F128(FUNC, PREFIX, ARGS) \
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_Float128 (FUNC ## f128) (ARGS (_Float128)) asm (PREFIX #FUNC "f128");
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# else
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# define MATH_REDIRECT_F128(FUNC, PREFIX, ARGS)
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# endif
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# define MATH_REDIRECT_UNARY_ARGS(TYPE) TYPE
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# define MATH_REDIRECT_BINARY_ARGS(TYPE) TYPE, TYPE
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# define MATH_REDIRECT_TERNARY_ARGS(TYPE) TYPE, TYPE, TYPE
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MATH_REDIRECT (sqrt, "__ieee754_", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (ceil, "__", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (floor, "__", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (roundeven, "__", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (rint, "__", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (trunc, "__", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (round, "__", MATH_REDIRECT_UNARY_ARGS)
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MATH_REDIRECT (copysign, "__", MATH_REDIRECT_BINARY_ARGS)
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MATH_REDIRECT (fma, "__", MATH_REDIRECT_TERNARY_ARGS)
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# endif
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# endif
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#endif
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#endif
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