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This patch continues cleaning up math_private.h by moving the math_opt_barrier and math_force_eval macros to a separate header math-barriers.h. At present, those macros are inside a "#ifndef math_opt_barrier" in math_private.h to allow architectures to override them and then use a separate math-barriers.h header, no such #ifndef or #include_next is needed; architectures just have their own alternative version of math-barriers.h when providing their own optimized versions that avoid going through memory unnecessarily. The generic math-barriers.h has a comment added to document these two macros. In this patch, math_private.h is made to #include <math-barriers.h>, so files using these macros do not need updating yet. That is because of uses of math_force_eval in math_check_force_underflow and math_check_force_underflow_nonneg, which are still defined in math_private.h. Once those are moved out to a separate header, that separate header can be made to include <math-barriers.h>, as can the other files directly using these barrier macros, and then the include of <math-barriers.h> from math_private.h can be removed. Tested for x86_64 and x86. Also tested with build-many-glibcs.py that installed stripped shared libraries are unchanged by this patch. * sysdeps/generic/math-barriers.h: New file. * sysdeps/generic/math_private.h [!math_opt_barrier] (math_opt_barrier): Move to math-barriers.h. [!math_opt_barrier] (math_force_eval): Likewise. * sysdeps/aarch64/fpu/math-barriers.h: New file. * sysdeps/aarch64/fpu/math_private.h (math_opt_barrier): Move to math-barriers.h. (math_force_eval): Likewise. * sysdeps/alpha/fpu/math-barriers.h: New file. * sysdeps/alpha/fpu/math_private.h (math_opt_barrier): Move to math-barriers.h. (math_force_eval): Likewise. * sysdeps/x86/fpu/math-barriers.h: New file. * sysdeps/i386/fpu/fenv_private.h (math_opt_barrier): Move to math-barriers.h. (math_force_eval): Likewise. * sysdeps/m68k/m680x0/fpu/math_private.h: Move to.... * sysdeps/m68k/m680x0/fpu/math-barriers.h: ... here. Adjust multiple-include guard for rename. * sysdeps/powerpc/fpu/math-barriers.h: New file. * sysdeps/powerpc/fpu/math_private.h (math_opt_barrier): Move to math-barriers.h. (math_force_eval): Likewise.
38 lines
1.7 KiB
C
38 lines
1.7 KiB
C
/* Control when floating-point expressions are evaluated. Generic version.
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Copyright (C) 2007-2018 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _MATH_BARRIERS_H
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#define _MATH_BARRIERS_H 1
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/* math_opt_barrier evaluates and returns its floating-point argument
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and ensures that the evaluation of any expression using the result
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of math_opt_barrier is not moved before the call. math_force_eval
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ensures that its floating-point argument is evaluated for its side
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effects even if its value is apparently unused, and that the
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evaluation of its argument is not moved after the call. Both these
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macros are used to ensure the correct ordering of floating-point
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expression evaluations with respect to accesses to the
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floating-point environment. */
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#define math_opt_barrier(x) \
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({ __typeof (x) __x = (x); __asm ("" : "+m" (__x)); __x; })
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#define math_force_eval(x) \
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({ __typeof (x) __x = (x); __asm __volatile__ ("" : : "m" (__x)); })
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#endif /* math-barriers.h */
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