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Various floating-point functions have code to force underflow
exceptions if a tiny result was computed in a way that might not have
resulted in such exceptions even though the result is inexact. This
typically uses math_force_eval to ensure that the underflowing
expression is evaluated, but sometimes uses volatile.
This patch refactors such code to use three new macros
math_check_force_underflow, math_check_force_underflow_nonneg and
math_check_force_underflow_complex (which in turn use
math_force_eval). In the limited number of cases not suited to a
simple conversion to these macros, existing uses of volatile are
changed to use math_force_eval instead. The converted code does not
always execute exactly the same sequence of operations as the original
code, but the overall effects should be the same.
Tested for x86_64, x86, mips64 and powerpc.
* sysdeps/generic/math_private.h (fabs_tg): New macro.
(min_of_type): Likewise.
(math_check_force_underflow): Likewise.
(math_check_force_underflow_nonneg): Likewise.
(math_check_force_underflow_complex): Likewise.
* math/e_exp2l.c (__ieee754_exp2l): Use
math_check_force_underflow_nonneg.
* math/k_casinh.c (__kernel_casinh): Likewise.
* math/k_casinhf.c (__kernel_casinhf): Likewise.
* math/k_casinhl.c (__kernel_casinhl): Likewise.
* math/s_catan.c (__catan): Use
math_check_force_underflow_complex.
* math/s_catanf.c (__catanf): Likewise.
* math/s_catanh.c (__catanh): Likewise.
* math/s_catanhf.c (__catanhf): Likewise.
* math/s_catanhl.c (__catanhl): Likewise.
* math/s_catanl.c (__catanl): Likewise.
* math/s_ccosh.c (__ccosh): Likewise.
* math/s_ccoshf.c (__ccoshf): Likewise.
* math/s_ccoshl.c (__ccoshl): Likewise.
* math/s_cexp.c (__cexp): Likewise.
* math/s_cexpf.c (__cexpf): Likewise.
* math/s_cexpl.c (__cexpl): Likewise.
* math/s_clog.c (__clog): Use math_check_force_underflow_nonneg.
* math/s_clog10.c (__clog10): Likewise.
* math/s_clog10f.c (__clog10f): Likewise.
* math/s_clog10l.c (__clog10l): Likewise.
* math/s_clogf.c (__clogf): Likewise.
* math/s_clogl.c (__clogl): Likewise.
* math/s_csin.c (__csin): Use math_check_force_underflow_complex.
* math/s_csinf.c (__csinf): Likewise.
* math/s_csinh.c (__csinh): Likewise.
* math/s_csinhf.c (__csinhf): Likewise.
* math/s_csinhl.c (__csinhl): Likewise.
* math/s_csinl.c (__csinl): Likewise.
* math/s_csqrt.c (__csqrt): Use math_check_force_underflow.
* math/s_csqrtf.c (__csqrtf): Likewise.
* math/s_csqrtl.c (__csqrtl): Likewise.
* math/s_ctan.c (__ctan): Use math_check_force_underflow_complex.
* math/s_ctanf.c (__ctanf): Likewise.
* math/s_ctanh.c (__ctanh): Likewise.
* math/s_ctanhf.c (__ctanhf): Likewise.
* math/s_ctanhl.c (__ctanhl): Likewise.
* math/s_ctanl.c (__ctanl): Likewise.
* stdlib/strtod_l.c (round_and_return): Use math_force_eval
instead of volatile.
* sysdeps/ieee754/dbl-64/e_asin.c (__ieee754_asin): Use
math_check_force_underflow.
* sysdeps/ieee754/dbl-64/e_atanh.c (__ieee754_atanh): Likewise.
* sysdeps/ieee754/dbl-64/e_exp.c (__ieee754_exp): Do not use
volatile when forcing underflow.
* sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/dbl-64/e_gamma_r.c (__ieee754_gamma_r):
Likewise.
* sysdeps/ieee754/dbl-64/e_j1.c (__ieee754_j1): Use
math_check_force_underflow.
* sysdeps/ieee754/dbl-64/e_jn.c (__ieee754_jn): Likewise.
* sysdeps/ieee754/dbl-64/e_sinh.c (__ieee754_sinh): Likewise.
* sysdeps/ieee754/dbl-64/s_asinh.c (__asinh): Likewise.
* sysdeps/ieee754/dbl-64/s_atan.c (atan): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/dbl-64/s_erf.c (__erf): Use
math_check_force_underflow.
* sysdeps/ieee754/dbl-64/s_expm1.c (__expm1): Likewise.
* sysdeps/ieee754/dbl-64/s_fma.c (__fma): Use math_force_eval
instead of volatile.
* sysdeps/ieee754/dbl-64/s_log1p.c (__log1p): Use
math_check_force_underflow.
* sysdeps/ieee754/dbl-64/s_sin.c (__sin): Likewise.
* sysdeps/ieee754/dbl-64/s_tan.c (tan): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/dbl-64/s_tanh.c (__tanh): Use
math_check_force_underflow.
* sysdeps/ieee754/flt-32/e_asinf.c (__ieee754_asinf): Likewise.
* sysdeps/ieee754/flt-32/e_atanhf.c (__ieee754_atanhf): Likewise.
* sysdeps/ieee754/flt-32/e_exp2f.c (__ieee754_exp2f): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/flt-32/e_gammaf_r.c (__ieee754_gammaf_r):
Likewise.
* sysdeps/ieee754/flt-32/e_j1f.c (__ieee754_j1f): Use
math_check_force_underflow.
* sysdeps/ieee754/flt-32/e_jnf.c (__ieee754_jnf): Likewise.
* sysdeps/ieee754/flt-32/e_sinhf.c (__ieee754_sinhf): Likewise.
* sysdeps/ieee754/flt-32/k_sinf.c (__kernel_sinf): Likewise.
* sysdeps/ieee754/flt-32/k_tanf.c (__kernel_tanf): Likewise.
* sysdeps/ieee754/flt-32/s_asinhf.c (__asinhf): Likewise.
* sysdeps/ieee754/flt-32/s_atanf.c (__atanf): Likewise.
* sysdeps/ieee754/flt-32/s_erff.c (__erff): Likewise.
* sysdeps/ieee754/flt-32/s_expm1f.c (__expm1f): Likewise.
* sysdeps/ieee754/flt-32/s_log1pf.c (__log1pf): Likewise.
* sysdeps/ieee754/flt-32/s_tanhf.c (__tanhf): Likewise.
* sysdeps/ieee754/ldbl-128/e_asinl.c (__ieee754_asinl): Likewise.
* sysdeps/ieee754/ldbl-128/e_atanhl.c (__ieee754_atanhl):
Likewise.
* sysdeps/ieee754/ldbl-128/e_expl.c (__ieee754_expl): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/ldbl-128/e_gammal_r.c (__ieee754_gammal_r):
Likewise.
* sysdeps/ieee754/ldbl-128/e_j1l.c (__ieee754_j1l): Use
math_check_force_underflow.
* sysdeps/ieee754/ldbl-128/e_jnl.c (__ieee754_jnl): Likewise.
* sysdeps/ieee754/ldbl-128/e_sinhl.c (__ieee754_sinhl): Likewise.
* sysdeps/ieee754/ldbl-128/k_sincosl.c (__kernel_sincosl):
Likewise.
* sysdeps/ieee754/ldbl-128/k_sinl.c (__kernel_sinl): Likewise.
* sysdeps/ieee754/ldbl-128/k_tanl.c (__kernel_tanl): Likewise.
* sysdeps/ieee754/ldbl-128/s_asinhl.c (__asinhl): Likewise.
* sysdeps/ieee754/ldbl-128/s_atanl.c (__atanl): Likewise.
* sysdeps/ieee754/ldbl-128/s_erfl.c (__erfl): Likewise.
* sysdeps/ieee754/ldbl-128/s_expm1l.c (__expm1l): Likewise.
* sysdeps/ieee754/ldbl-128/s_fmal.c (__fmal): Use math_force_eval
instead of volatile.
* sysdeps/ieee754/ldbl-128/s_log1pl.c (__log1pl): Use
math_check_force_underflow.
* sysdeps/ieee754/ldbl-128/s_tanhl.c (__tanhl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_asinl.c (__ieee754_asinl): Use
math_check_force_underflow.
* sysdeps/ieee754/ldbl-128ibm/e_atanhl.c (__ieee754_atanhl):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/e_gammal_r.c (__ieee754_gammal_r):
Use math_check_force_underflow_nonneg.
* sysdeps/ieee754/ldbl-128ibm/e_jnl.c (__ieee754_jnl): Use
math_check_force_underflow.
* sysdeps/ieee754/ldbl-128ibm/e_sinhl.c (__ieee754_sinhl):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/k_sincosl.c (__kernel_sincosl):
Likewise.
* sysdeps/ieee754/ldbl-128ibm/k_sinl.c (__kernel_sinl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/k_tanl.c (__kernel_tanl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_asinhl.c (__asinhl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_atanl.c (__atanl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_erfl.c (__erfl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_tanhl.c (__tanhl): Likewise.
* sysdeps/ieee754/ldbl-96/e_asinl.c (__ieee754_asinl): Likewise.
* sysdeps/ieee754/ldbl-96/e_atanhl.c (__ieee754_atanhl): Likewise.
* sysdeps/ieee754/ldbl-96/e_gammal_r.c (__ieee754_gammal_r): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/ldbl-96/e_j1l.c (__ieee754_j1l): Use
math_check_force_underflow.
* sysdeps/ieee754/ldbl-96/e_jnl.c (__ieee754_jnl): Likewise.
* sysdeps/ieee754/ldbl-96/e_sinhl.c (__ieee754_sinhl): Likewise.
* sysdeps/ieee754/ldbl-96/k_sinl.c (__kernel_sinl): Likewise.
* sysdeps/ieee754/ldbl-96/k_tanl.c (__kernel_tanl): Use
math_check_force_underflow_nonneg.
* sysdeps/ieee754/ldbl-96/s_asinhl.c (__asinhl): Use
math_check_force_underflow.
* sysdeps/ieee754/ldbl-96/s_erfl.c (__erfl): Likewise.
* sysdeps/ieee754/ldbl-96/s_fmal.c (__fmal): Use math_force_eval
instead of volatile.
* sysdeps/ieee754/ldbl-96/s_tanhl.c (__tanhl): Use
math_check_force_underflow.
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cexp, ccos, ccosh, csin and csinh have spurious underflows in cases
where they compute sin of the smallest normal, that produces an
underflow exception (depending on which sin implementation is in use)
but the final result does not underflow. ctan and ctanh may also have
such underflows, or they may be latent (the issue there is that
e.g. ctan (DBL_MIN) should, rounded upwards, be the next double value
above DBL_MIN, which under glibc's accuracy goals may not have an
underflow exception, but the intermediate computation of sin (DBL_MIN)
would legitimately underflow on before-rounding architectures).
This patch fixes all those functions so they use plain comparisons (>
DBL_MIN etc.) instead of comparing the result of fpclassify with
FP_SUBNORMAL (in all these cases, we already know the number being
compared is finite). Note that in the case of csin / csinf / csinl,
there is no need for fabs calls in the comparison because the real
part has already been reduced to its absolute value.
As the patch fixes the failures that previously obstructed moving
tests of cexp to use ALL_RM_TEST, those tests are moved to ALL_RM_TEST
by the patch (two functions remain yet to be converted).
Tested for x86_64 and x86 and ulps updated accordingly.
[BZ #18594]
* math/s_ccosh.c (__ccosh): Compare with least normal value
instead of comparing class with FP_SUBNORMAL.
* math/s_ccoshf.c (__ccoshf): Likewise.
* math/s_ccoshl.c (__ccoshl): Likewise.
* math/s_cexp.c (__cexp): Likewise.
* math/s_cexpf.c (__cexpf): Likewise.
* math/s_cexpl.c (__cexpl): Likewise.
* math/s_csin.c (__csin): Likewise.
* math/s_csinf.c (__csinf): Likewise.
* math/s_csinh.c (__csinh): Likewise.
* math/s_csinhf.c (__csinhf): Likewise.
* math/s_csinhl.c (__csinhl): Likewise.
* math/s_csinl.c (__csinl): Likewise.
* math/s_ctan.c (__ctan): Likewise.
* math/s_ctanf.c (__ctanf): Likewise.
* math/s_ctanh.c (__ctanh): Likewise.
* math/s_ctanhf.c (__ctanhf): Likewise.
* math/s_ctanhl.c (__ctanhl): Likewise.
* math/s_ctanl.c (__ctanl): Likewise.
* math/auto-libm-test-in: Add more tests of ccos, ccosh, cexp,
csin, csinh, ctan and ctanh.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (cexp_test): Use ALL_RM_TEST.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
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