https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88502
Bug ID: 88502
Summary: Inline built-in asinh, acosh, atanh for -ffast-math
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: jsm28 at gcc dot gnu.org
Target Milestone: ---
Target: i?86-*-*
GCC should support inline code generation for asinh, acosh, atanh functions,
under appropriate fast-math conditions.
glibc's bits/mathinline.h, for 32-bit non-SSE fast-math x86 only, has:
/* The argument range of the inline version of asinhl is slightly reduced. */
__inline_mathcodeNP (asinh, __x, \
register long double __y = __fabsl (__x); \
return (log1pl (__y * __y / (__libc_sqrtl (__y * __y + 1.0) + 1.0) + __y) \
* __sgn1l (__x)))
__inline_mathcodeNP (acosh, __x, \
return logl (__x + __libc_sqrtl (__x - 1.0) * __libc_sqrtl (__x + 1.0)))
__inline_mathcodeNP (atanh, __x, \
register long double __y = __fabsl (__x); \
return -0.5 * log1pl (-(__y + __y) / (1.0 + __y)) * __sgn1l (__x))
We're moving away from such inlines in glibc, preferring to leave it to the
compiler to inline standard functions under appropriate conditions. This
inlining probably only makes sense when logl / log1pl are themselves expanded
inline (but in principle it's otherwise generic; note this x86 code uses long
double, so avoiding reducing the argument range for built-in functions for
narrower types). (__sgn1l is another inline function, copying the sign of x to
the value 1.0L.)
