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Diffstat (limited to 'contrib/llvm-project/compiler-rt/lib/builtins/fp_lib.h')
| -rw-r--r-- | contrib/llvm-project/compiler-rt/lib/builtins/fp_lib.h | 416 |
1 files changed, 416 insertions, 0 deletions
diff --git a/contrib/llvm-project/compiler-rt/lib/builtins/fp_lib.h b/contrib/llvm-project/compiler-rt/lib/builtins/fp_lib.h new file mode 100644 index 000000000000..b2a89506135b --- /dev/null +++ b/contrib/llvm-project/compiler-rt/lib/builtins/fp_lib.h @@ -0,0 +1,416 @@ +//===-- lib/fp_lib.h - Floating-point utilities -------------------*- C -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file is a configuration header for soft-float routines in compiler-rt. +// This file does not provide any part of the compiler-rt interface, but defines +// many useful constants and utility routines that are used in the +// implementation of the soft-float routines in compiler-rt. +// +// Assumes that float, double and long double correspond to the IEEE-754 +// binary32, binary64 and binary 128 types, respectively, and that integer +// endianness matches floating point endianness on the target platform. +// +//===----------------------------------------------------------------------===// + +#ifndef FP_LIB_HEADER +#define FP_LIB_HEADER + +#include "int_lib.h" +#include "int_math.h" +#include "int_types.h" +#include <limits.h> +#include <stdbool.h> +#include <stdint.h> + +#if defined SINGLE_PRECISION + +typedef uint16_t half_rep_t; +typedef uint32_t rep_t; +typedef uint64_t twice_rep_t; +typedef int32_t srep_t; +typedef float fp_t; +#define HALF_REP_C UINT16_C +#define REP_C UINT32_C +#define significandBits 23 + +static __inline int rep_clz(rep_t a) { return clzsi(a); } + +// 32x32 --> 64 bit multiply +static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { + const uint64_t product = (uint64_t)a * b; + *hi = (rep_t)(product >> 32); + *lo = (rep_t)product; +} +COMPILER_RT_ABI fp_t __addsf3(fp_t a, fp_t b); + +#elif defined DOUBLE_PRECISION + +typedef uint32_t half_rep_t; +typedef uint64_t rep_t; +typedef int64_t srep_t; +typedef double fp_t; +#define HALF_REP_C UINT32_C +#define REP_C UINT64_C +#define significandBits 52 + +static inline int rep_clz(rep_t a) { return __builtin_clzll(a); } + +#define loWord(a) (a & 0xffffffffU) +#define hiWord(a) (a >> 32) + +// 64x64 -> 128 wide multiply for platforms that don't have such an operation; +// many 64-bit platforms have this operation, but they tend to have hardware +// floating-point, so we don't bother with a special case for them here. +static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { + // Each of the component 32x32 -> 64 products + const uint64_t plolo = loWord(a) * loWord(b); + const uint64_t plohi = loWord(a) * hiWord(b); + const uint64_t philo = hiWord(a) * loWord(b); + const uint64_t phihi = hiWord(a) * hiWord(b); + // Sum terms that contribute to lo in a way that allows us to get the carry + const uint64_t r0 = loWord(plolo); + const uint64_t r1 = hiWord(plolo) + loWord(plohi) + loWord(philo); + *lo = r0 + (r1 << 32); + // Sum terms contributing to hi with the carry from lo + *hi = hiWord(plohi) + hiWord(philo) + hiWord(r1) + phihi; +} +#undef loWord +#undef hiWord + +COMPILER_RT_ABI fp_t __adddf3(fp_t a, fp_t b); + +#elif defined QUAD_PRECISION +#if defined(CRT_HAS_F128) && defined(CRT_HAS_128BIT) +typedef uint64_t half_rep_t; +typedef __uint128_t rep_t; +typedef __int128_t srep_t; +typedef tf_float fp_t; +#define HALF_REP_C UINT64_C +#define REP_C (__uint128_t) +#if defined(CRT_HAS_IEEE_TF) +// Note: Since there is no explicit way to tell compiler the constant is a +// 128-bit integer, we let the constant be casted to 128-bit integer +#define significandBits 112 +#define TF_MANT_DIG (significandBits + 1) + +static __inline int rep_clz(rep_t a) { + const union { + __uint128_t ll; +#if _YUGA_BIG_ENDIAN + struct { + uint64_t high, low; + } s; +#else + struct { + uint64_t low, high; + } s; +#endif + } uu = {.ll = a}; + + uint64_t word; + uint64_t add; + + if (uu.s.high) { + word = uu.s.high; + add = 0; + } else { + word = uu.s.low; + add = 64; + } + return __builtin_clzll(word) + add; +} + +#define Word_LoMask UINT64_C(0x00000000ffffffff) +#define Word_HiMask UINT64_C(0xffffffff00000000) +#define Word_FullMask UINT64_C(0xffffffffffffffff) +#define Word_1(a) (uint64_t)((a >> 96) & Word_LoMask) +#define Word_2(a) (uint64_t)((a >> 64) & Word_LoMask) +#define Word_3(a) (uint64_t)((a >> 32) & Word_LoMask) +#define Word_4(a) (uint64_t)(a & Word_LoMask) + +// 128x128 -> 256 wide multiply for platforms that don't have such an operation; +// many 64-bit platforms have this operation, but they tend to have hardware +// floating-point, so we don't bother with a special case for them here. +static __inline void wideMultiply(rep_t a, rep_t b, rep_t *hi, rep_t *lo) { + + const uint64_t product11 = Word_1(a) * Word_1(b); + const uint64_t product12 = Word_1(a) * Word_2(b); + const uint64_t product13 = Word_1(a) * Word_3(b); + const uint64_t product14 = Word_1(a) * Word_4(b); + const uint64_t product21 = Word_2(a) * Word_1(b); + const uint64_t product22 = Word_2(a) * Word_2(b); + const uint64_t product23 = Word_2(a) * Word_3(b); + const uint64_t product24 = Word_2(a) * Word_4(b); + const uint64_t product31 = Word_3(a) * Word_1(b); + const uint64_t product32 = Word_3(a) * Word_2(b); + const uint64_t product33 = Word_3(a) * Word_3(b); + const uint64_t product34 = Word_3(a) * Word_4(b); + const uint64_t product41 = Word_4(a) * Word_1(b); + const uint64_t product42 = Word_4(a) * Word_2(b); + const uint64_t product43 = Word_4(a) * Word_3(b); + const uint64_t product44 = Word_4(a) * Word_4(b); + + const __uint128_t sum0 = (__uint128_t)product44; + const __uint128_t sum1 = (__uint128_t)product34 + (__uint128_t)product43; + const __uint128_t sum2 = + (__uint128_t)product24 + (__uint128_t)product33 + (__uint128_t)product42; + const __uint128_t sum3 = (__uint128_t)product14 + (__uint128_t)product23 + + (__uint128_t)product32 + (__uint128_t)product41; + const __uint128_t sum4 = + (__uint128_t)product13 + (__uint128_t)product22 + (__uint128_t)product31; + const __uint128_t sum5 = (__uint128_t)product12 + (__uint128_t)product21; + const __uint128_t sum6 = (__uint128_t)product11; + + const __uint128_t r0 = (sum0 & Word_FullMask) + ((sum1 & Word_LoMask) << 32); + const __uint128_t r1 = (sum0 >> 64) + ((sum1 >> 32) & Word_FullMask) + + (sum2 & Word_FullMask) + ((sum3 << 32) & Word_HiMask); + + *lo = r0 + (r1 << 64); + *hi = (r1 >> 64) + (sum1 >> 96) + (sum2 >> 64) + (sum3 >> 32) + sum4 + + (sum5 << 32) + (sum6 << 64); +} +#undef Word_1 +#undef Word_2 +#undef Word_3 +#undef Word_4 +#undef Word_HiMask +#undef Word_LoMask +#undef Word_FullMask +#endif // defined(CRT_HAS_IEEE_TF) +#else +typedef long double fp_t; +#endif // defined(CRT_HAS_F128) && defined(CRT_HAS_128BIT) +#else +#error SINGLE_PRECISION, DOUBLE_PRECISION or QUAD_PRECISION must be defined. +#endif + +#if defined(SINGLE_PRECISION) || defined(DOUBLE_PRECISION) || \ + (defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE)) +#define typeWidth (sizeof(rep_t) * CHAR_BIT) + +static __inline rep_t toRep(fp_t x) { + const union { + fp_t f; + rep_t i; + } rep = {.f = x}; + return rep.i; +} + +static __inline fp_t fromRep(rep_t x) { + const union { + fp_t f; + rep_t i; + } rep = {.i = x}; + return rep.f; +} + +#if !defined(QUAD_PRECISION) || defined(CRT_HAS_IEEE_TF) +#define exponentBits (typeWidth - significandBits - 1) +#define maxExponent ((1 << exponentBits) - 1) +#define exponentBias (maxExponent >> 1) + +#define implicitBit (REP_C(1) << significandBits) +#define significandMask (implicitBit - 1U) +#define signBit (REP_C(1) << (significandBits + exponentBits)) +#define absMask (signBit - 1U) +#define exponentMask (absMask ^ significandMask) +#define oneRep ((rep_t)exponentBias << significandBits) +#define infRep exponentMask +#define quietBit (implicitBit >> 1) +#define qnanRep (exponentMask | quietBit) + +static __inline int normalize(rep_t *significand) { + const int shift = rep_clz(*significand) - rep_clz(implicitBit); + *significand <<= shift; + return 1 - shift; +} + +static __inline void wideLeftShift(rep_t *hi, rep_t *lo, unsigned int count) { + *hi = *hi << count | *lo >> (typeWidth - count); + *lo = *lo << count; +} + +static __inline void wideRightShiftWithSticky(rep_t *hi, rep_t *lo, + unsigned int count) { + if (count < typeWidth) { + const bool sticky = (*lo << (typeWidth - count)) != 0; + *lo = *hi << (typeWidth - count) | *lo >> count | sticky; + *hi = *hi >> count; + } else if (count < 2 * typeWidth) { + const bool sticky = *hi << (2 * typeWidth - count) | *lo; + *lo = *hi >> (count - typeWidth) | sticky; + *hi = 0; + } else { + const bool sticky = *hi | *lo; + *lo = sticky; + *hi = 0; + } +} + +// Implements logb methods (logb, logbf, logbl) for IEEE-754. This avoids +// pulling in a libm dependency from compiler-rt, but is not meant to replace +// it (i.e. code calling logb() should get the one from libm, not this), hence +// the __compiler_rt prefix. +static __inline fp_t __compiler_rt_logbX(fp_t x) { + rep_t rep = toRep(x); + int exp = (rep & exponentMask) >> significandBits; + + // Abnormal cases: + // 1) +/- inf returns +inf; NaN returns NaN + // 2) 0.0 returns -inf + if (exp == maxExponent) { + if (((rep & signBit) == 0) || (x != x)) { + return x; // NaN or +inf: return x + } else { + return -x; // -inf: return -x + } + } else if (x == 0.0) { + // 0.0: return -inf + return fromRep(infRep | signBit); + } + + if (exp != 0) { + // Normal number + return exp - exponentBias; // Unbias exponent + } else { + // Subnormal number; normalize and repeat + rep &= absMask; + const int shift = 1 - normalize(&rep); + exp = (rep & exponentMask) >> significandBits; + return exp - exponentBias - shift; // Unbias exponent + } +} + +// Avoid using scalbn from libm. Unlike libc/libm scalbn, this function never +// sets errno on underflow/overflow. +static __inline fp_t __compiler_rt_scalbnX(fp_t x, int y) { + const rep_t rep = toRep(x); + int exp = (rep & exponentMask) >> significandBits; + + if (x == 0.0 || exp == maxExponent) + return x; // +/- 0.0, NaN, or inf: return x + + // Normalize subnormal input. + rep_t sig = rep & significandMask; + if (exp == 0) { + exp += normalize(&sig); + sig &= ~implicitBit; // clear the implicit bit again + } + + if (__builtin_sadd_overflow(exp, y, &exp)) { + // Saturate the exponent, which will guarantee an underflow/overflow below. + exp = (y >= 0) ? INT_MAX : INT_MIN; + } + + // Return this value: [+/-] 1.sig * 2 ** (exp - exponentBias). + const rep_t sign = rep & signBit; + if (exp >= maxExponent) { + // Overflow, which could produce infinity or the largest-magnitude value, + // depending on the rounding mode. + return fromRep(sign | ((rep_t)(maxExponent - 1) << significandBits)) * 2.0f; + } else if (exp <= 0) { + // Subnormal or underflow. Use floating-point multiply to handle truncation + // correctly. + fp_t tmp = fromRep(sign | (REP_C(1) << significandBits) | sig); + exp += exponentBias - 1; + if (exp < 1) + exp = 1; + tmp *= fromRep((rep_t)exp << significandBits); + return tmp; + } else + return fromRep(sign | ((rep_t)exp << significandBits) | sig); +} + +#endif // !defined(QUAD_PRECISION) || defined(CRT_HAS_IEEE_TF) + +// Avoid using fmax from libm. +static __inline fp_t __compiler_rt_fmaxX(fp_t x, fp_t y) { + // If either argument is NaN, return the other argument. If both are NaN, + // arbitrarily return the second one. Otherwise, if both arguments are +/-0, + // arbitrarily return the first one. + return (crt_isnan(x) || x < y) ? y : x; +} + +#endif + +#if defined(SINGLE_PRECISION) + +static __inline fp_t __compiler_rt_logbf(fp_t x) { + return __compiler_rt_logbX(x); +} +static __inline fp_t __compiler_rt_scalbnf(fp_t x, int y) { + return __compiler_rt_scalbnX(x, y); +} +static __inline fp_t __compiler_rt_fmaxf(fp_t x, fp_t y) { +#if defined(__aarch64__) + // Use __builtin_fmaxf which turns into an fmaxnm instruction on AArch64. + return __builtin_fmaxf(x, y); +#else + // __builtin_fmaxf frequently turns into a libm call, so inline the function. + return __compiler_rt_fmaxX(x, y); +#endif +} + +#elif defined(DOUBLE_PRECISION) + +static __inline fp_t __compiler_rt_logb(fp_t x) { + return __compiler_rt_logbX(x); +} +static __inline fp_t __compiler_rt_scalbn(fp_t x, int y) { + return __compiler_rt_scalbnX(x, y); +} +static __inline fp_t __compiler_rt_fmax(fp_t x, fp_t y) { +#if defined(__aarch64__) + // Use __builtin_fmax which turns into an fmaxnm instruction on AArch64. + return __builtin_fmax(x, y); +#else + // __builtin_fmax frequently turns into a libm call, so inline the function. + return __compiler_rt_fmaxX(x, y); +#endif +} + +#elif defined(QUAD_PRECISION) && defined(CRT_HAS_TF_MODE) +// The generic implementation only works for ieee754 floating point. For other +// floating point types, continue to rely on the libm implementation for now. +#if defined(CRT_HAS_IEEE_TF) +static __inline tf_float __compiler_rt_logbtf(tf_float x) { + return __compiler_rt_logbX(x); +} +static __inline tf_float __compiler_rt_scalbntf(tf_float x, int y) { + return __compiler_rt_scalbnX(x, y); +} +static __inline tf_float __compiler_rt_fmaxtf(tf_float x, tf_float y) { + return __compiler_rt_fmaxX(x, y); +} +#define __compiler_rt_logbl __compiler_rt_logbtf +#define __compiler_rt_scalbnl __compiler_rt_scalbntf +#define __compiler_rt_fmaxl __compiler_rt_fmaxtf +#define crt_fabstf crt_fabsf128 +#define crt_copysigntf crt_copysignf128 +#elif defined(CRT_LDBL_128BIT) +static __inline tf_float __compiler_rt_logbtf(tf_float x) { + return crt_logbl(x); +} +static __inline tf_float __compiler_rt_scalbntf(tf_float x, int y) { + return crt_scalbnl(x, y); +} +static __inline tf_float __compiler_rt_fmaxtf(tf_float x, tf_float y) { + return crt_fmaxl(x, y); +} +#define __compiler_rt_logbl crt_logbl +#define __compiler_rt_scalbnl crt_scalbnl +#define __compiler_rt_fmaxl crt_fmaxl +#define crt_fabstf crt_fabsl +#define crt_copysigntf crt_copysignl +#else +#error Unsupported TF mode type +#endif + +#endif // *_PRECISION + +#endif // FP_LIB_HEADER |
