[Libclc-dev] [PATCH] Implement tanh builtin
Niels Ole Salscheider via Libclc-dev
libclc-dev at lists.llvm.org
Sat Sep 26 01:35:06 PDT 2015
This is a port from the AMD builtin library.
---
generic/include/clc/clc.h | 1 +
generic/include/clc/math/{atan.h => tanh.h} | 2 +-
generic/include/clc/math/{atan.inc => tanh.inc} | 2 +-
generic/lib/SOURCES | 1 +
generic/lib/math/tanh.cl | 146 ++++++++++++++++++++++++
5 files changed, 150 insertions(+), 2 deletions(-)
copy generic/include/clc/math/{atan.h => tanh.h} (96%)
copy generic/include/clc/math/{atan.inc => tanh.inc} (94%)
create mode 100644 generic/lib/math/tanh.cl
diff --git a/generic/include/clc/clc.h b/generic/include/clc/clc.h
index cab751d..d34a540 100644
--- a/generic/include/clc/clc.h
+++ b/generic/include/clc/clc.h
@@ -77,6 +77,7 @@
#include <clc/math/sinpi.h>
#include <clc/math/sqrt.h>
#include <clc/math/tan.h>
+#include <clc/math/tanh.h>
#include <clc/math/trunc.h>
#include <clc/math/native_cos.h>
#include <clc/math/native_divide.h>
diff --git a/generic/include/clc/math/atan.h b/generic/include/clc/math/tanh.h
similarity index 96%
copy from generic/include/clc/math/atan.h
copy to generic/include/clc/math/tanh.h
index d969719..e895ee4 100644
--- a/generic/include/clc/math/atan.h
+++ b/generic/include/clc/math/tanh.h
@@ -20,5 +20,5 @@
* THE SOFTWARE.
*/
-#define __CLC_BODY <clc/math/atan.inc>
+#define __CLC_BODY <clc/math/tanh.inc>
#include <clc/math/gentype.inc>
diff --git a/generic/include/clc/math/atan.inc b/generic/include/clc/math/tanh.inc
similarity index 94%
copy from generic/include/clc/math/atan.inc
copy to generic/include/clc/math/tanh.inc
index d217c95..f0735e9 100644
--- a/generic/include/clc/math/atan.inc
+++ b/generic/include/clc/math/tanh.inc
@@ -20,4 +20,4 @@
* THE SOFTWARE.
*/
-_CLC_OVERLOAD _CLC_DECL __CLC_GENTYPE atan(__CLC_GENTYPE a);
+_CLC_OVERLOAD _CLC_DECL __CLC_GENTYPE tanh(__CLC_GENTYPE a);
diff --git a/generic/lib/SOURCES b/generic/lib/SOURCES
index a5ee9f8..ff4e18f 100644
--- a/generic/lib/SOURCES
+++ b/generic/lib/SOURCES
@@ -109,6 +109,7 @@ math/sinpi.cl
math/clc_sqrt.cl
math/sqrt.cl
math/tan.cl
+math/tanh.cl
relational/all.cl
relational/any.cl
relational/bitselect.cl
diff --git a/generic/lib/math/tanh.cl b/generic/lib/math/tanh.cl
new file mode 100644
index 0000000..e9c4079
--- /dev/null
+++ b/generic/lib/math/tanh.cl
@@ -0,0 +1,146 @@
+/*
+ * Copyright (c) 2014 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <clc/clc.h>
+
+#include "math.h"
+#include "../clcmacro.h"
+
+_CLC_OVERLOAD _CLC_DEF float tanh(float x)
+{
+ // The definition of tanh(x) is sinh(x)/cosh(x), which is also equivalent
+ // to the following three formulae:
+ // 1. (exp(x) - exp(-x))/(exp(x) + exp(-x))
+ // 2. (1 - (2/(exp(2*x) + 1 )))
+ // 3. (exp(2*x) - 1)/(exp(2*x) + 1)
+ // but computationally, some formulae are better on some ranges.
+
+ const float large_threshold = 0x1.0a2b24p+3f;
+
+ uint ux = as_uint(x);
+ uint aux = ux & EXSIGNBIT_SP32;
+ uint xs = ux ^ aux;
+
+ float y = as_float(aux);
+ float y2 = y*y;
+
+ float a1 = mad(y2,
+ mad(y2, 0.4891631088530669873e-4F, -0.14628356048797849e-2F),
+ -0.28192806108402678e0F);
+ float b1 = mad(y2, 0.3427017942262751343e0F, 0.845784192581041099e0F);
+
+ float a2 = mad(y2,
+ mad(y2, 0.3827534993599483396e-4F, -0.12325644183611929e-2F),
+ -0.24069858695196524e0F);
+ float b2 = mad(y2, 0.292529068698052819e0F, 0.72209738473684982e0F);
+
+ int c = y < 0.9f;
+ float a = c ? a1 : a2;
+ float b = c ? b1 : b2;
+ float zlo = mad(MATH_DIVIDE(a, b), y*y2, y);
+
+ float p = exp(2.0f * y) + 1.0f;
+ float zhi = 1.0F - MATH_DIVIDE(2.0F, p);
+
+ float z = y <= 1.0f ? zlo : zhi;
+ z = as_float(xs | as_uint(z));
+
+ // Edge cases
+ float sone = as_float(0x3f800000U | xs);
+ z = y > large_threshold ? sone : z;
+ z = aux < 0x39000000 | aux > 0x7f800000 ? x : z;
+
+ return z;
+}
+
+_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, float, tanh, float);
+
+#ifdef cl_khr_fp64
+
+#pragma OPENCL EXTENSION cl_khr_fp64 : enable
+
+_CLC_OVERLOAD _CLC_DEF double tanh(double x)
+{
+ // The definition of tanh(x) is sinh(x)/cosh(x), which is also equivalent
+ // to the following three formulae:
+ // 1. (exp(x) - exp(-x))/(exp(x) + exp(-x))
+ // 2. (1 - (2/(exp(2*x) + 1 )))
+ // 3. (exp(2*x) - 1)/(exp(2*x) + 1)
+ // but computationally, some formulae are better on some ranges.
+
+ // The point at which e^-x is insignificant compared to e^x = ln(2^27)
+ const double large_threshold = 0x1.2b708872320e2p+4;
+
+ ulong ux = as_ulong(x);
+ ulong ax = ux & ~SIGNBIT_DP64;
+ ulong sx = ux ^ ax;
+ double y = as_double(ax);
+ double y2 = y * y;
+
+ // y < 0.9
+ double znl = fma(y2,
+ fma(y2,
+ fma(y2, -0.142077926378834722618091e-7, -0.200047621071909498730453e-3),
+ -0.176016349003044679402273e-1),
+ -0.274030424656179760118928e0);
+
+ double zdl = fma(y2,
+ fma(y2,
+ fma(y2, 0.2091140262529164482568557e-3, 0.201562166026937652780575e-1),
+ 0.381641414288328849317962e0),
+ 0.822091273968539282568011e0);
+
+ // 0.9 <= y <= 1
+ double znm = fma(y2,
+ fma(y2,
+ fma(y2, -0.115475878996143396378318e-7, -0.165597043903549960486816e-3),
+ -0.146173047288731678404066e-1),
+ -0.227793870659088295252442e0);
+
+ double zdm = fma(y2,
+ fma(y2,
+ fma(y2, 0.173076050126225961768710e-3, 0.167358775461896562588695e-1),
+ 0.317204558977294374244770e0),
+ 0.683381611977295894959554e0);
+
+ int c = y < 0.9;
+ double zn = c ? znl : znm;
+ double zd = c ? zdl : zdm;
+ double z = y + y*y2 * MATH_DIVIDE(zn, zd);
+
+ // y > 1
+ double p = exp(2.0 * y) + 1.0;
+ double zg = 1.0 - 2.0 / p;
+
+ z = y > 1.0 ? zg : z;
+
+ // Other cases
+ z = y < 0x1.0p-28 | ax > PINFBITPATT_DP64 ? x : z;
+
+ z = y > large_threshold ? 1.0 : z;
+
+ return as_double(sx | as_ulong(z));
+}
+
+_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, double, tanh, double);
+
+#endif // cl_khr_fp64
--
2.5.3
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