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6f0f237bf5
i386 exp, hypot and pow functions can return overflowing and underflowing values with excess range and precision; ; Wilco Dijkstra's patches to make isfinite etc. expand inline cause this pre-existing issue to result in test failures. This patch fixes those functions to avoid excess range and precision in their return values. Appropriate macros are added for the repeated code sequences; in future I'll add more such macros and refactor existing code forcing underflow (with or without also eliminating excess range and precision from the return value) to use such macros. Tested for x86. If, after this patch, you still see x86 libm test failures with excess range or precision, please file bugs in Bugzilla. [BZ #18980] * sysdeps/i386/fpu/i386-math-asm.h (DEFINE_FLT_MIN): New macro. (DEFINE_DBL_MIN): Likewise. (FLT_NARROW_EVAL_UFLOW_NONNEG_NAN): Likewise. (DBL_NARROW_EVAL_UFLOW_NONNEG_NAN): Likewise. (FLT_NARROW_EVAL_UFLOW_NONNEG): Likewise. (DBL_NARROW_EVAL_UFLOW_NONNEG): Likewise. * sysdeps/i386/fpu/e_exp.S: Include <i386-math-asm.h>. (dbl_min): Replace with use of DEFINE_DBL_MIN. (__ieee754_exp): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN. (__exp_finite): Use DBL_NARROW_EVAL_UFLOW_NONNEG. * sysdeps/i386/fpu/e_exp10.S: Include <i386-math-asm.h>. (dbl_min): Replace with use of DEFINE_DBL_MIN. (__ieee754_exp10): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_exp10f.S: Include <i386-math-asm.h>. (flt_min): Replace with use of DEFINE_FLT_MIN. (__ieee754_exp10f): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_exp2.S: Include <i386-math-asm.h>. (dbl_min): Replace with use of DEFINE_DBL_MIN. (__ieee754_exp2): Use DBL_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_exp2f.S: Include <i386-math-asm.h>. (flt_min): Replace with use of DEFINE_FLT_MIN. (__ieee754_exp2f): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN. * sysdeps/i386/fpu/e_expf.S: Include <i386-math-asm.h>. (flt_min): Replace with use of DEFINE_FLT_MIN. (__ieee754_expf): Use FLT_NARROW_EVAL_UFLOW_NONNEG_NAN. (__expf_finite): Use FLT_NARROW_EVAL_UFLOW_NONNEG. * sysdeps/i386/fpu/e_hypot.S: Include <i386-math-asm.h>. (__ieee754_hypot): Use DBL_NARROW_EVAL. * sysdeps/i386/fpu/e_hypotf.S: Include <i386-math-asm.h>. (__ieee754_hypotf): Use FLT_NARROW_EVAL. * sysdeps/i386/fpu/e_pow.S: Include <i386-math-asm.h>. (__ieee754_pow): Use DBL_NARROW_EVAL. * sysdeps/i386/fpu/e_powf.S: Include <i386-math-asm.h>. (__ieee754_powf): Use FLT_NARROW_EVAL. * sysdeps/i386/i686/fpu/multiarch/e_expf-sse2.S (__ieee754_expf_sse2): Convert double-precision result to single precision. * sysdeps/i386/fpu/libm-test-ulps: Update.
127 lines
3.5 KiB
C
127 lines
3.5 KiB
C
/* Helper macros for x86 libm functions.
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Copyright (C) 2015 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 _I386_MATH_ASM_H
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#define _I386_MATH_ASM_H 1
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/* Remove excess range and precision by storing a value on the stack
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and loading it back. */
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#define FLT_NARROW_EVAL \
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subl $4, %esp; \
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cfi_adjust_cfa_offset (4); \
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fstps (%esp); \
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flds (%esp); \
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addl $4, %esp; \
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cfi_adjust_cfa_offset (-4);
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#define DBL_NARROW_EVAL \
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subl $8, %esp; \
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cfi_adjust_cfa_offset (8); \
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fstpl (%esp); \
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fldl (%esp); \
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addl $8, %esp; \
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cfi_adjust_cfa_offset (-8);
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/* Define constants for the minimum value of a floating-point
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type. */
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#define DEFINE_FLT_MIN \
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.section .rodata.cst4,"aM",@progbits,4; \
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.p2align 2; \
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.type flt_min,@object; \
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flt_min: \
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.byte 0, 0, 0x80, 0; \
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.size flt_min, .-flt_min;
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#define DEFINE_DBL_MIN \
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.section .rodata.cst8,"aM",@progbits,8; \
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.p2align 3; \
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.type dbl_min,@object; \
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dbl_min: \
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.byte 0, 0, 0, 0, 0, 0, 0x10, 0; \
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.size dbl_min, .-dbl_min;
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/* Remove excess range and precision by storing a value on the stack
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and loading it back. The value is given to be nonnegative or NaN;
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if it is subnormal, also force an underflow exception. The
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relevant constant for the minimum of the type must have been
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defined, the MO macro must have been defined for access to memory
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operands, and, if PIC, the PIC register must have been loaded. */
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#define FLT_NARROW_EVAL_UFLOW_NONNEG_NAN \
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subl $4, %esp; \
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cfi_adjust_cfa_offset (4); \
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flds MO(flt_min); \
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fld %st(1); \
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fucompp; \
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fnstsw; \
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sahf; \
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jnc 6424f; \
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fld %st(0); \
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fmul %st(0); \
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fstps (%esp); \
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6424: fstps (%esp); \
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flds (%esp); \
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addl $4, %esp; \
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cfi_adjust_cfa_offset (-4);
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#define DBL_NARROW_EVAL_UFLOW_NONNEG_NAN \
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subl $8, %esp; \
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cfi_adjust_cfa_offset (8); \
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fldl MO(dbl_min); \
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fld %st(1); \
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fucompp; \
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fnstsw; \
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sahf; \
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jnc 6453f; \
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fld %st(0); \
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fmul %st(0); \
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fstpl (%esp); \
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6453: fstpl (%esp); \
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fldl (%esp); \
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addl $8, %esp; \
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cfi_adjust_cfa_offset (-8);
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/* Likewise, but the argument is not a NaN (so fcom instructions,
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which support memory operands, can be used). */
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#define FLT_NARROW_EVAL_UFLOW_NONNEG \
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subl $4, %esp; \
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cfi_adjust_cfa_offset (4); \
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fcoms MO(flt_min); \
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fnstsw; \
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sahf; \
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jnc 6424f; \
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fld %st(0); \
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fmul %st(0); \
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fstps (%esp); \
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6424: fstps (%esp); \
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flds (%esp); \
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addl $4, %esp; \
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cfi_adjust_cfa_offset (-4);
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#define DBL_NARROW_EVAL_UFLOW_NONNEG \
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subl $8, %esp; \
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cfi_adjust_cfa_offset (8); \
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fcoml MO(dbl_min); \
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fnstsw; \
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sahf; \
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jnc 6453f; \
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fld %st(0); \
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fmul %st(0); \
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fstpl (%esp); \
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6453: fstpl (%esp); \
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fldl (%esp); \
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addl $8, %esp; \
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cfi_adjust_cfa_offset (-8);
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#endif /* i386-math-asm.h. */
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