__kernel_standard_l converts long double arguments to double for use
in SVID "struct exception". This has special-case handling for when
that conversion would overflow or underflow but the original long
double function wouldn't. However, it turns out that "inexact"
exceptions can be spurious here as well, when the function is exactly
determined and __kernel_standard_l is being called for a domain error.
This patch fixes this by using feholdexcept / fesetenv to avoid
exceptions from the conversion, replacing the previous special-case
logic for overflow and underflow (this covers all functions using
__kernel_standard_l, not just those that actually need a change, since
there doesn't seem to be much point in restricting things just to the
functions that mustn't get "inexact" here).
Tested for x86_64 and x86.
[BZ #18245]
[BZ #18583]
* sysdeps/ieee754/k_standardl.c: Include <fenv.h>.
(__kernel_standard_l): Use feholdexcept and fesetenv around
conversion to double instead of special-casing overflow and
underflow.
* math/libm-test.inc (fmod_test_data): Add more tests.
(remainder_test_data): Likewise.
(sqrt_test_data): Likewise.
Bug 17724 reports references to fesetround being brought in by
ldbl-128ibm rintl via references to __rintl from __kernel_standard_l.
Because all three __kernel_standard* functions are in the same file,
this gets brought in even though only the long double version
__kernel_standard_l needs __rintl, and the C90 functions use only
__kernel_standard.
This patch fixes this by splitting the three versions into separate
files; it's fine for long double functions to refer to fe* functions
directly, unless they get called by C90 double functions.
Tested for x86_64 (testsuite; the reordering of code means disassembly
of shared libraries can't usefully be compared). Tested for powerpc
that the relevant issue disappears from the linknamespace test
output.
[BZ #17724]
* sysdeps/ieee754/k_standard.c: Don't include <float.h>.
(__kernel_standard_f): Remove. Moved to k_standardf.c.
(__kernel_standard_l): Remove. Moved to k_standardl.c with
(char *) casts added.
* sysdeps/ieee754/k_standardf.c: New file.
* sysdeps/ieee754/k_standardl.c: Likewise.
* math/Makefile (libm-support): Remove k_standard.
(libm-calls): Add k_standard.
Joseph Myers