[llvm-branch-commits] [libclc] libclc: Update atan2pi (PR #188707)
Matt Arsenault via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Thu Mar 26 02:12:55 PDT 2026
https://github.com/arsenm created https://github.com/llvm/llvm-project/pull/188707
This was originally ported from rocm device libs in
37406a209c75a09f850cd5e5498568d34a6f05d1. Merge in more
recent changes.
>From 778637dec2a35b6fa8ba0c3c1d659651960e4b09 Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault at amd.com>
Date: Thu, 19 Mar 2026 16:35:31 +0100
Subject: [PATCH] libclc: Update atan2pi
This was originally ported from rocm device libs in
37406a209c75a09f850cd5e5498568d34a6f05d1. Merge in more
recent changes.
---
libclc/clc/lib/generic/math/clc_atan2pi.cl | 10 +-
libclc/clc/lib/generic/math/clc_atan2pi.inc | 263 ++++++--------------
2 files changed, 75 insertions(+), 198 deletions(-)
diff --git a/libclc/clc/lib/generic/math/clc_atan2pi.cl b/libclc/clc/lib/generic/math/clc_atan2pi.cl
index cee4d8451d85a..cd18b4876da86 100644
--- a/libclc/clc/lib/generic/math/clc_atan2pi.cl
+++ b/libclc/clc/lib/generic/math/clc_atan2pi.cl
@@ -6,19 +6,19 @@
//
//===----------------------------------------------------------------------===//
-#include "clc/clc_convert.h"
#include "clc/float/definitions.h"
#include "clc/internal/clc.h"
+#include "clc/math/clc_atan_helpers.h"
#include "clc/math/clc_copysign.h"
#include "clc/math/clc_fabs.h"
#include "clc/math/clc_fma.h"
-#include "clc/math/clc_ldexp.h"
+#include "clc/math/clc_fmax.h"
+#include "clc/math/clc_fmin.h"
#include "clc/math/clc_mad.h"
-#include "clc/math/math.h"
-#include "clc/math/tables.h"
#include "clc/relational/clc_isinf.h"
-#include "clc/relational/clc_isnan.h"
+#include "clc/relational/clc_isunordered.h"
#include "clc/relational/clc_select.h"
+#include "clc/relational/clc_signbit.h"
#include "clc/shared/clc_max.h"
#include "clc/shared/clc_min.h"
diff --git a/libclc/clc/lib/generic/math/clc_atan2pi.inc b/libclc/clc/lib/generic/math/clc_atan2pi.inc
index 9f901947887d8..76b5e45547173 100644
--- a/libclc/clc/lib/generic/math/clc_atan2pi.inc
+++ b/libclc/clc/lib/generic/math/clc_atan2pi.inc
@@ -6,222 +6,99 @@
//
//===----------------------------------------------------------------------===//
-#if __CLC_FPSIZE == 32
-
-_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_atan2pi(__CLC_GENTYPE y,
- __CLC_GENTYPE x) {
- const __CLC_GENTYPE pi = 0x1.921fb6p+1f;
-
- __CLC_GENTYPE ax = __clc_fabs(x);
- __CLC_GENTYPE ay = __clc_fabs(y);
- __CLC_GENTYPE v = __clc_min(ax, ay);
- __CLC_GENTYPE u = __clc_max(ax, ay);
+#pragma OPENCL FP_CONTRACT OFF
- // Scale since u could be large, as in "regular" divide
- __CLC_GENTYPE s = u > 0x1.0p+96f ? 0x1.0p-32f : 1.0f;
- __CLC_GENTYPE vbyu = s * MATH_DIVIDE(v, s * u);
+#if __CLC_FPSIZE == 32
- __CLC_GENTYPE vbyu2 = vbyu * vbyu;
+_CLC_DEF _CLC_OVERLOAD _CLC_CONST __CLC_FLOATN __clc_atan2pi(__CLC_FLOATN y,
+ __CLC_FLOATN x) {
+ __CLC_FLOATN ax = __clc_fabs(x);
+ __CLC_FLOATN ay = __clc_fabs(y);
+ __CLC_FLOATN v = __clc_fmin(ax, ay);
+ __CLC_FLOATN u = __clc_fmax(ax, ay);
- __CLC_GENTYPE p =
- __clc_mad(vbyu2, __clc_mad(vbyu2, -0x1.7e1f78p-9f, -0x1.7d1b98p-3f),
- -0x1.5554d0p-2f) *
- vbyu2 * vbyu;
- __CLC_GENTYPE q =
- __clc_mad(vbyu2, __clc_mad(vbyu2, 0x1.1a714cp-2f, 0x1.287c56p+0f), 1.0f);
+ __CLC_FLOATN vbyu = v / u;
- // Octant 0 result
- __CLC_GENTYPE a = MATH_DIVIDE(__clc_mad(p, MATH_RECIP(q), vbyu), pi);
+ __CLC_FLOATN a = __clc_atanpi_reduced(vbyu);
- // Fix up 3 other octants
- __CLC_GENTYPE at = 0.5f - a;
+ __CLC_FLOATN at = 0.5f - a;
a = ay > ax ? at : a;
at = 1.0f - a;
- a = x < 0.0F ? at : a;
+ a = x < 0.0f ? at : a;
- // y == 0 => 0 for x >= 0, pi for x < 0
- at = __CLC_AS_INTN(x) < 0 ? 1.0f : 0.0f;
+ at = __clc_signbit(x) ? 1.0f : 0.0f;
a = y == 0.0f ? at : a;
// x and y are +- Inf
- at = x > 0.0f ? 0.25f : 0.75f;
- a = __clc_select(a, at, __clc_isinf(x) && __clc_isinf(y));
+ at = x < 0.0f ? 0.75f : 0.25f;
+ a = (__clc_isinf(x) & __clc_isinf(y)) ? at : a;
// x or y is NaN
- a = __clc_select(a, __CLC_GENTYPE_NAN, __clc_isnan(x) || __clc_isnan(y));
+ a = __clc_isunordered(x, y) ? FLT_NAN : a;
- // Fixup sign and return
return __clc_copysign(a, y);
}
#elif __CLC_FPSIZE == 64
-_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_atan2pi(__CLC_GENTYPE y,
- __CLC_GENTYPE x) {
- const __CLC_GENTYPE pi = 3.1415926535897932e+00; /* 0x400921fb54442d18 */
- const __CLC_GENTYPE pi_head = 3.1415926218032836e+00; /* 0x400921fb50000000 */
- const __CLC_GENTYPE pi_tail = 3.1786509547056392e-08; /* 0x3e6110b4611a6263 */
- // 0x3ff921fb54442d18
- const __CLC_GENTYPE piby2_head = 1.5707963267948965e+00;
- // 0x3c91a62633145c07
- const __CLC_GENTYPE piby2_tail = 6.1232339957367660e-17;
-
- __CLC_GENTYPE x2 = x;
- __CLC_LONGN xneg = __CLC_AS_LONGN(x) < 0;
- __CLC_INTN xexp =
- __CLC_CONVERT_INTN(__CLC_AS_ULONGN(x) >> EXPSHIFTBITS_DP64) & 0x7ff;
-
- __CLC_GENTYPE y2 = y;
- __CLC_LONGN yneg = __CLC_AS_LONGN(y) < 0;
- __CLC_INTN yexp =
- __CLC_CONVERT_INTN(__CLC_AS_ULONGN(y) >> EXPSHIFTBITS_DP64) & 0x7ff;
-
- __CLC_LONGN cond2 = __CLC_CONVERT_LONGN(xexp < 1021 & yexp < 1021);
- __CLC_LONGN diffexp = __CLC_CONVERT_LONGN(yexp - xexp);
-
- // Scale up both x and y if they are both below 1/4
- __CLC_GENTYPE x1 = __clc_ldexp(x, 1024);
- __CLC_INTN xexp1 =
- __CLC_CONVERT_INTN(__CLC_AS_ULONGN(x1) >> EXPSHIFTBITS_DP64) & 0x7ff;
- __CLC_GENTYPE y1 = __clc_ldexp(y, 1024);
- __CLC_INTN yexp1 =
- __CLC_CONVERT_INTN(__CLC_AS_ULONGN(y1) >> EXPSHIFTBITS_DP64) & 0x7ff;
- __CLC_LONGN diffexp1 = __CLC_CONVERT_LONGN(yexp1 - xexp1);
-
- diffexp = __clc_select(diffexp, diffexp1, cond2);
- x = cond2 ? x1 : x;
- y = cond2 ? y1 : y;
-
- // General case: take absolute values of arguments
- __CLC_GENTYPE u = __clc_fabs(x);
- __CLC_GENTYPE v = __clc_fabs(y);
-
- // Swap u and v if necessary to obtain 0 < v < u. Compute v/u.
- __CLC_LONGN swap_vu = u < v;
- __CLC_GENTYPE uu = u;
- u = swap_vu ? v : u;
- v = swap_vu ? uu : v;
-
- __CLC_GENTYPE vbyu = v / u;
- __CLC_GENTYPE q1, q2;
-
- // General values of v/u. Use a look-up table and series expansion.
-
- {
- __CLC_GENTYPE val = vbyu > 0.0625 ? vbyu : 0.063;
- __CLC_INTN index = __CLC_CONVERT_INTN(__clc_fma(256.0, val, 0.5));
- q1 = __CLC_USE_TABLE(atan_jby256_tbl_head, (index - 16));
- q2 = __CLC_USE_TABLE(atan_jby256_tbl_tail, (index - 16));
- __CLC_GENTYPE c = __CLC_CONVERT_GENTYPE(index) * 0x1.0p-8;
-
- // We're going to scale u and v by 2^(-u_exponent) to bring them close to 1
- // u_exponent could be EMAX so we have to do it in 2 steps
- __CLC_INTN m =
- -(__CLC_CONVERT_INTN(__CLC_AS_ULONGN(u) >> EXPSHIFTBITS_DP64) -
- EXPBIAS_DP64);
- __CLC_GENTYPE um = __clc_ldexp(u, m);
- __CLC_GENTYPE vm = __clc_ldexp(v, m);
-
- // 26 leading bits of u
- __CLC_GENTYPE u1 =
- __CLC_AS_GENTYPE(__CLC_AS_ULONGN(um) & 0xfffffffff8000000UL);
- __CLC_GENTYPE u2 = um - u1;
-
- __CLC_GENTYPE r = MATH_DIVIDE(__clc_fma(-c, u2, __clc_fma(-c, u1, vm)),
- __clc_fma(c, vm, um));
-
- // Polynomial approximation to atan(r)
- __CLC_GENTYPE s = r * r;
- q2 = q2 + __clc_fma((s * __clc_fma(-s, 0.19999918038989143496,
- 0.33333333333224095522)),
- -r, r);
- }
-
- __CLC_GENTYPE q3, q4;
- {
- q3 = 0.0;
- q4 = vbyu;
- }
-
- __CLC_GENTYPE q5, q6;
- {
- __CLC_GENTYPE u1 =
- __CLC_AS_GENTYPE(__CLC_AS_ULONGN(u) & 0xffffffff00000000UL);
- __CLC_GENTYPE u2 = u - u1;
- __CLC_GENTYPE vu1 =
- __CLC_AS_GENTYPE(__CLC_AS_ULONGN(vbyu) & 0xffffffff00000000UL);
- __CLC_GENTYPE vu2 = vbyu - vu1;
-
- q5 = 0.0;
- __CLC_GENTYPE s = vbyu * vbyu;
- q6 = vbyu +
- __clc_fma(
- -vbyu * s,
- __clc_fma(
- -s,
- __clc_fma(-s,
- __clc_fma(-s,
- __clc_fma(-s, 0.90029810285449784439E-01,
- 0.11110736283514525407),
- 0.14285713561807169030),
- 0.19999999999393223405),
- 0.33333333333333170500),
- MATH_DIVIDE(__clc_fma(-u, vu2,
- __clc_fma(-u2, vu1, __clc_fma(-u1, vu1, v))),
- u));
- }
-
- q3 = vbyu < 0x1.d12ed0af1a27fp-27 ? q3 : q5;
- q4 = vbyu < 0x1.d12ed0af1a27fp-27 ? q4 : q6;
-
- q1 = vbyu > 0.0625 ? q1 : q3;
- q2 = vbyu > 0.0625 ? q2 : q4;
-
- // Tidy-up according to which quadrant the arguments lie in
- __CLC_GENTYPE res1, res2, res3, res4;
- q1 = swap_vu ? piby2_head - q1 : q1;
- q2 = swap_vu ? piby2_tail - q2 : q2;
- q1 = xneg ? pi_head - q1 : q1;
- q2 = xneg ? pi_tail - q2 : q2;
- q1 = MATH_DIVIDE(q1 + q2, pi);
- res4 = yneg ? -q1 : q1;
-
- res1 = yneg ? -0.75 : 0.75;
- res2 = yneg ? -0.25 : 0.25;
- res3 = xneg ? res1 : res2;
-
- res3 = __clc_select(res4, res3,
- __CLC_CONVERT_LONGN(__clc_isinf(y2) & __clc_isinf(x2)));
- res1 = yneg ? -1.0 : 1.0;
-
- // abs(x)/abs(y) > 2^56 and x < 0
- res3 = diffexp < -56 && xneg ? res1 : res3;
-
- res4 = MATH_DIVIDE(MATH_DIVIDE(y, x), pi);
- // x positive and dominant over y by a factor of 2^28
- res3 = diffexp < -28 && xneg == 0 ? res4 : res3;
-
- // abs(y)/abs(x) > 2^56
- res4 = yneg ? -0.5 : 0.5; // atan(y/x) is insignificant compared to piby2
- res3 = diffexp > 56 ? res4 : res3;
-
- res3 = x2 == 0.0 ? res4 : res3; // Zero x gives +- pi/2 depending on sign of y
- res4 = xneg ? res1 : y2;
-
- // Zero y gives +-0 for positive x and +-pi for negative x
- res3 = y2 == 0.0 ? res4 : res3;
- res3 = __clc_isnan(y2) ? y2 : res3;
- res3 = __clc_isnan(x2) ? x2 : res3;
-
- return res3;
+_CLC_DEF _CLC_OVERLOAD _CLC_CONST __CLC_DOUBLEN __clc_atan2pi(__CLC_DOUBLEN y,
+ __CLC_DOUBLEN x) {
+ __CLC_DOUBLEN ay = __clc_fabs(y);
+ __CLC_DOUBLEN ax = __clc_fabs(x);
+ __CLC_DOUBLEN u = __clc_fmax(ax, ay);
+ __CLC_DOUBLEN v = __clc_fmin(ax, ay);
+ __CLC_DOUBLEN vbyu = v / u;
+
+ __CLC_DOUBLEN a = __clc_atanpi_reduced(vbyu);
+
+ __CLC_LONGN xneg = __clc_signbit(x);
+
+ __CLC_DOUBLEN t = 0.5 - a;
+ a = ax < ay ? t : a;
+ t = 1.0 - a;
+ a = xneg ? t : a;
+
+ t = xneg ? 1.0 : 0.0;
+ a = y == 0.0 ? t : a;
+
+ t = xneg ? 0.75 : 0.25;
+ t = __clc_copysign(t, y);
+ a = (__clc_isinf(x) & __clc_isinf(y)) ? t : a;
+
+ a = __clc_isunordered(x, y) ? DBL_NAN : a;
+
+ return __clc_copysign(a, y);
}
#elif __CLC_FPSIZE == 16
-_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE __clc_atan2pi(__CLC_GENTYPE x,
- __CLC_GENTYPE y) {
- return __CLC_CONVERT_GENTYPE(
- __clc_atan2pi(__CLC_CONVERT_FLOATN(x), __CLC_CONVERT_FLOATN(y)));
+_CLC_DEF _CLC_OVERLOAD _CLC_CONST __CLC_HALFN __clc_atan2pi(__CLC_HALFN y,
+ __CLC_HALFN x) {
+ __CLC_HALFN ax = __clc_fabs(x);
+ __CLC_HALFN ay = __clc_fabs(y);
+ __CLC_HALFN v = __clc_fmin(ax, ay);
+ __CLC_HALFN u = __clc_fmax(ax, ay);
+
+ __CLC_HALFN vbyu = v / u;
+
+ __CLC_HALFN a = __clc_atanpi_reduced(vbyu);
+
+ __CLC_HALFN at = 0.5h - a;
+ a = ay > ax ? at : a;
+ at = 1.0h - a;
+ a = x < 0.0h ? at : a;
+
+ at = __clc_signbit(x) ? 1.0h : 0.0h;
+ a = y == 0.0h ? at : a;
+
+ // x and y are +- Inf
+ at = x < 0.0h ? 0.75h : 0.25h;
+ a = (__clc_isinf(x) & __clc_isinf(y)) ? at : a;
+
+ // x or y is NaN
+ a = __clc_isunordered(x, y) ? HALF_NAN : a;
+
+ return __clc_copysign(a, y);
}
#endif
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