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[libclc] Improve nextafter behaviour around zero #127469

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Merged
merged 2 commits into from
Feb 19, 2025
Merged

[libclc] Improve nextafter behaviour around zero #127469

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dbe1d8d
[libclc] Improve nextafter behaviour around zero
frasercrmck Feb 17, 2025
e25ac41
change abs vars to float
frasercrmck Feb 19, 2025
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36 changes: 23 additions & 13 deletions libclc/clc/lib/generic/math/clc_nextafter.cl
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#include <clc/clcmacro.h>
#include <clc/internal/clc.h>
#include <clc/math/clc_fabs.h>
#include <clc/relational/clc_isnan.h>

// This file provides OpenCL C implementations of __clc_nextafter for
Expand All @@ -12,21 +13,30 @@
FLOAT_TYPE y) { \
const UINT_TYPE sign_bit = (UINT_TYPE)1 \
<< (sizeof(INT_TYPE_SCALAR) * 8 - 1); \
const UINT_TYPE sign_bit_mask = sign_bit - (UINT_TYPE)1; \
INT_TYPE ix = CLC_AS_TYPE(INT_TYPE)(x); \
UINT_TYPE ax = CLC_AS_TYPE(UINT_TYPE)(ix) & sign_bit_mask; \
INT_TYPE mx = CLC_AS_TYPE(INT_TYPE)(sign_bit) - ix; \
mx = CLC_AS_TYPE(INT_TYPE)(ix) < (INT_TYPE)0 ? mx : ix; \
INT_TYPE iy = CLC_AS_TYPE(INT_TYPE)(y); \
UINT_TYPE ay = CLC_AS_TYPE(UINT_TYPE)(iy) & sign_bit_mask; \
INT_TYPE my = CLC_AS_TYPE(INT_TYPE)(sign_bit) - iy; \
my = iy < (INT_TYPE)0 ? my : iy; \
UINT_TYPE ix = CLC_AS_TYPE(UINT_TYPE)(x); \
FLOAT_TYPE absx = __clc_fabs(x); \
UINT_TYPE mxu = sign_bit - ix; \
INT_TYPE mx = CLC_AS_TYPE(INT_TYPE)(mxu); \
mx = CLC_AS_TYPE(INT_TYPE)(ix) < (INT_TYPE)0 ? mx \
: CLC_AS_TYPE(INT_TYPE)(ix); \
UINT_TYPE iy = CLC_AS_TYPE(UINT_TYPE)(y); \
FLOAT_TYPE absy = __clc_fabs(y); \
UINT_TYPE myu = sign_bit - iy; \
INT_TYPE my = CLC_AS_TYPE(INT_TYPE)(myu); \
my = CLC_AS_TYPE(INT_TYPE)(iy) < (INT_TYPE)0 ? my \
: CLC_AS_TYPE(INT_TYPE)(iy); \
INT_TYPE t = mx + (mx < my ? (INT_TYPE)1 : (INT_TYPE)-1); \
INT_TYPE r = CLC_AS_TYPE(INT_TYPE)(sign_bit) - t; \
r = t < (INT_TYPE)0 ? r : t; \
UINT_TYPE r = sign_bit - CLC_AS_TYPE(UINT_TYPE)(t); \
r = (t < (INT_TYPE)0 || (t == (INT_TYPE)0 && mx < my)) \
? r \
: CLC_AS_TYPE(UINT_TYPE)(t); \
r = __clc_isnan(x) ? ix : r; \
r = __clc_isnan(y) ? CLC_AS_TYPE(INT_TYPE)(iy) : r; \
r = ((ax | ay) == (UINT_TYPE)0 || ix == iy) ? iy : r; \
r = __clc_isnan(y) ? iy : r; \
r = ((CLC_AS_TYPE(UINT_TYPE)(absx) | CLC_AS_TYPE(UINT_TYPE)(absy)) == \
(UINT_TYPE)0 || \
ix == iy) \
? iy \
: r; \
return CLC_AS_TYPE(FLOAT_TYPE)(r); \
}

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