Implement atanpi builtin

This implementation was ported from the AMD builtin library
and has been tested with piglit, OpenCV, and the ocl conformance tests.

git-svn-id: https://llvm.org/svn/llvm-project/libclc/trunk@233928 91177308-0d34-0410-b5e6-96231b3b80d8

5 files changed, 231 insertions, 0 deletions

diff --git a/generic/include/clc/clc.h b/generic/include/clc/clc.h
index d55c0e6..3c76978 100644
--- a/generic/include/clc/clc.h
+++ b/generic/include/clc/clc.h
@@ -39,6 +39,7 @@
 #include <clc/math/asinpi.h>
 #include <clc/math/atan.h>
 #include <clc/math/atan2.h>
+#include <clc/math/atanpi.h>
 #include <clc/math/copysign.h>
 #include <clc/math/cos.h>
 #include <clc/math/cospi.h>
diff --git a/generic/include/clc/math/atanpi.h b/generic/include/clc/math/atanpi.h
new file mode 100644
index 0000000..ada3fbe
--- /dev/null
+++ b/generic/include/clc/math/atanpi.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (c) 2014, 2015 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.
+ */
+
+#define __CLC_BODY <clc/math/atanpi.inc>
+#include <clc/math/gentype.inc>
diff --git a/generic/include/clc/math/atanpi.inc b/generic/include/clc/math/atanpi.inc
new file mode 100644
index 0000000..e97c806
--- /dev/null
+++ b/generic/include/clc/math/atanpi.inc
@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2014, 2015 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.
+ */
+
+_CLC_OVERLOAD _CLC_DECL __CLC_GENTYPE atanpi(__CLC_GENTYPE x);
diff --git a/generic/lib/SOURCES b/generic/lib/SOURCES
index 1aadebf..beaa7e2 100644
--- a/generic/lib/SOURCES
+++ b/generic/lib/SOURCES
@@ -66,6 +66,7 @@ math/asinh.cl
 math/asinpi.cl
 math/atan.cl
 math/atan2.cl
+math/atanpi.cl
 math/copysign.cl
 math/cos.cl
 math/cospi.cl
diff --git a/generic/lib/math/atanpi.cl b/generic/lib/math/atanpi.cl
new file mode 100644
index 0000000..2e2f032
--- /dev/null
+++ b/generic/lib/math/atanpi.cl
@@ -0,0 +1,182 @@
+/*
+ * Copyright (c) 2014,2015 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 atanpi(float x) {
+    const float pi = 3.1415926535897932f;
+
+    uint ux = as_uint(x);
+    uint aux = ux & EXSIGNBIT_SP32;
+    uint sx = ux ^ aux;
+
+    float xbypi = MATH_DIVIDE(x, pi);
+    float shalf = as_float(sx | as_uint(0.5f));
+
+    float v = as_float(aux);
+
+    // Return for NaN
+    float ret = x;
+
+    // 2^26 <= |x| <= Inf => atan(x) is close to piby2
+    ret = aux <= PINFBITPATT_SP32  ? shalf : ret;
+
+    // Reduce arguments 2^-19 <= |x| < 2^26
+
+    // 39/16 <= x < 2^26
+    x = -MATH_RECIP(v);
+    float c = 1.57079632679489655800f; // atan(infinity)
+
+    // 19/16 <= x < 39/16
+    int l = aux < 0x401c0000;
+    float xx = MATH_DIVIDE(v - 1.5f, mad(v, 1.5f, 1.0f));
+    x = l ? xx : x;
+    c = l ? 9.82793723247329054082e-01f : c; // atan(1.5)
+
+    // 11/16 <= x < 19/16
+    l = aux < 0x3f980000U;
+    xx =  MATH_DIVIDE(v - 1.0f, 1.0f + v);
+    x = l ? xx : x;
+    c = l ? 7.85398163397448278999e-01f : c; // atan(1)
+
+    // 7/16 <= x < 11/16
+    l = aux < 0x3f300000;
+    xx = MATH_DIVIDE(mad(v, 2.0f, -1.0f), 2.0f + v);
+    x = l ? xx : x;
+    c = l ? 4.63647609000806093515e-01f : c; // atan(0.5)
+
+    // 2^-19 <= x < 7/16
+    l = aux < 0x3ee00000;
+    x = l ? v : x;
+    c = l ? 0.0f : c;
+
+    // Core approximation: Remez(2,2) on [-7/16,7/16]
+
+    float s = x * x;
+    float a = mad(s,
+                  mad(s, 0.470677934286149214138357545549e-2f, 0.192324546402108583211697690500f),
+                  0.296528598819239217902158651186f);
+
+    float b = mad(s,
+                  mad(s, 0.299309699959659728404442796915f, 0.111072499995399550138837673349e1f),
+                  0.889585796862432286486651434570f);
+
+    float q = x * s * MATH_DIVIDE(a, b);
+
+    float z = c - (q - x);
+    z = MATH_DIVIDE(z, pi);
+    float zs = as_float(sx | as_uint(z));
+
+    ret  = aux < 0x4c800000 ?  zs : ret;
+
+    // |x| < 2^-19
+    ret = aux < 0x36000000 ? xbypi : ret;
+    return ret;
+}
+
+_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, float, atanpi, float)
+
+#ifdef cl_khr_fp64
+#pragma OPENCL EXTENSION cl_khr_fp64 : enable
+
+_CLC_OVERLOAD _CLC_DEF double atanpi(double x) {
+    const double pi = 0x1.921fb54442d18p+1;
+
+    double v = fabs(x);
+
+    // 2^56 > v > 39/16
+    double a = -1.0;
+    double b = v;
+    // (chi + clo) = arctan(infinity)
+    double chi = 1.57079632679489655800e+00;
+    double clo = 6.12323399573676480327e-17;
+
+    double ta = v - 1.5;
+    double tb = 1.0 + 1.5 * v;
+    int l = v <= 0x1.38p+1; // 39/16 > v > 19/16
+    a = l ? ta : a;
+    b = l ? tb : b;
+    // (chi + clo) = arctan(1.5)
+    chi = l ? 9.82793723247329054082e-01 : chi;
+    clo = l ? 1.39033110312309953701e-17 : clo;
+
+    ta = v - 1.0;
+    tb = 1.0 + v;
+    l = v <= 0x1.3p+0; // 19/16 > v > 11/16
+    a = l ? ta : a;
+    b = l ? tb : b;
+    // (chi + clo) = arctan(1.)
+    chi = l ? 7.85398163397448278999e-01 : chi;
+    clo = l ? 3.06161699786838240164e-17 : clo;
+
+    ta = 2.0 * v - 1.0;
+    tb = 2.0 + v;
+    l = v <= 0x1.6p-1; // 11/16 > v > 7/16
+    a = l ? ta : a;
+    b = l ? tb : b;
+    // (chi + clo) = arctan(0.5)
+    chi = l ? 4.63647609000806093515e-01 : chi;
+    clo = l ? 2.26987774529616809294e-17 : clo;
+
+    l = v <= 0x1.cp-2; // v < 7/16
+    a = l ? v : a;
+    b = l ? 1.0 : b;;
+    chi = l ? 0.0 : chi;
+    clo = l ? 0.0 : clo;
+
+    // Core approximation: Remez(4,4) on [-7/16,7/16]
+    double r = a / b;
+    double s = r * r;
+    double qn = fma(s,
+                    fma(s,
+                        fma(s,
+                            fma(s, 0.142316903342317766e-3,
+                                   0.304455919504853031e-1),
+                            0.220638780716667420e0),
+                        0.447677206805497472e0),
+                    0.268297920532545909e0);
+
+    double qd = fma(s,
+	            fma(s,
+			fma(s,
+			    fma(s, 0.389525873944742195e-1,
+				   0.424602594203847109e0),
+                            0.141254259931958921e1),
+                        0.182596787737507063e1),
+                    0.804893761597637733e0);
+
+    double q = r * s * qn / qd;
+    r = (chi - ((q - clo) - r)) / pi;
+    double vp = v / pi;
+
+    double z = isnan(x) ? x : 0.5;
+    z = v <= 0x1.0p+56 ? r : z;
+    z = v < 0x1.0p-26 ? vp : z;
+    return x == v ? z : -z;
+}
+
+_CLC_UNARY_VECTORIZE(_CLC_OVERLOAD _CLC_DEF, double, atanpi, double)
+
+#endif