TS 18661-1 defines canonicalize functions to produce a canonical
version of a floating-point representation. This patch implements
these functions for glibc.
As with the iscanonical macro, these functions are oriented to the
decimal floating-point case, where some values have both canonical and
noncanonical representations. However, the functions have a return
value that says whether they succeeded in storing a canonical result;
thus, they can fail for the case of an invalid representation (while
still not making any particular choice from among multiple equally
canonical valid representations of the same value). Since no
floating-point formats in glibc actually have noncanonical valid
representations, a type-generic implementation of these functions can
be used that expects iscanonical to return 0 only for invalid
representations. Now that iscanonical is used within libm.so,
libm_hidden_proto / libm_hidden_def are added for __iscanonicall.
The definition of these functions is intended to correspond to a
convertFormat operation to the same floating-point format. Thus, they
convert signaling NaNs to quiet NaNs, raising the "invalid" exception.
Such a conversion "should" produce "the canonical version of that
signaling NaN made quiet".
libm-test.inc is made to check NaN payloads for the output of these
functions, a new feature (at some point manipulation functions such as
fabs and copysign should have tests added that verify payload
preservation for them). As however some architectures may not follow
the recommended practice of preserving NaN payloads when converting a
signaling NaN to quiet, a new math-tests.h macro
SNAN_TESTS_PRESERVE_PAYLOAD is added, and defined to 0 for non-NAN2008
MIPS; any other architectures seeing test failures for lack of payload
preservation in this case should also define this macro to 0. (If any
cases arise where the sign isn't preserved either, those should have a
similar macro added.)
The ldbl-96 and ldbl-128ibm tests of iscanonical are renamed and
adapted to test canonicalizel as well on the same representations.
Tested for x86_64, x86, mips64 and powerpc.
* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
(canonicalize): New declaration.
* math/Versions (canonicalize): New libm symbol at version
GLIBC_2.25.
(canonicalizef): Likewise.
(canonicalizel): Likewise.
* math/Makefile (gen-libm-calls): Add s_canonicalizeF.
* math/s_canonicalize_template.c: New file.
* math/libm-test.inc: Update comment on functions tested and
testing of NaN payloads.
(TEST_NAN_PAYLOAD): New macro.
(NO_TEST_INLINE): Update value.
(XFAIL_TEST): Likewise.
(ERRNO_UNCHANGED): Likewise.
(ERRNO_EDOM): Likewise.
(ERRNO_ERANGE): Likewise.
(IGNORE_RESULT): Likewise.
(NON_FINITE): Likewise.
(TEST_SNAN): Likewise.
(NO_TEST_MATHVEC): Likewise.
(TEST_NAN_PAYLOAD_CANONICALIZE): New macro.
(check_float_internal): Check NaN payloads if TEST_NAN_PAYLOAD.
(struct test_Ffp_b1_data): New type.
(RUN_TEST_Ffp_b1): New macro.
(RUN_TEST_LOOP_Ffp_b1): Likewise.
(canonicalize_test_data): New array.
(canonicalize_test): New function.
(main): Call canonicalize_test.
* manual/arith.texi (FP Bit Twiddling): Document canonicalize,
canonicalizef and canonicalizel.
* manual/libm-err-tab.pl: Update comment on interfaces without
ulps tabulated.
* sysdeps/ieee754/ldbl-opt/nldbl-canonicalize.c: New file.
* sysdeps/ieee754/ldbl-opt/s_canonicalizel.c: Likewise.
* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add
canonicalize.
(CFLAGS-nldbl-canonicalize.c): New variable.
* sysdeps/ieee754/ldbl-128ibm/test-iscanonical-ldbl-128ibm.c: Move
to ...
* sysdeps/ieee754/ldbl-128ibm/test-canonical-ldbl-128ibm.c:
... here.
(do_test): Also test canonicalizel.
* sysdeps/ieee754/ldbl-128ibm/Makefile (tests): Change
test-iscanonical-ldbl-128ibm to test-canonical-ldbl-128ibm.
* sysdeps/ieee754/ldbl-128ibm/include/bits/iscanonical.h: New
file.
* sysdeps/ieee754/ldbl-128ibm/s_iscanonicall.c (__iscanonicall):
Use libm_hidden_def.
* sysdeps/ieee754/ldbl-96/test-iscanonical-ldbl-96.c: Move to ...
* sysdeps/ieee754/ldbl-96/test-canonical-ldbl-96.c: ... here.
(do_test): Also test canonicalizel.
* sysdeps/ieee754/ldbl-96/Makefile (tests): Change
test-iscanonical-ldbl-96 to test-canonical-ldbl-96.
* sysdeps/ieee754/ldbl-96/include/bits/iscanonical.h: New file.
* sysdeps/ieee754/ldbl-96/s_iscanonicall.c (__iscanonicall): Use
libm_hidden_def.
* sysdeps/generic/math-tests.h (SNAN_TESTS_PRESERVE_PAYLOAD): New
macro.
* sysdeps/mips/math-tests.h [__mips_hard_float && !__mips_nan2008]
(SNAN_TESTS_PRESERVE_PAYLOAD): Likewise.
* sysdeps/nacl/libm.abilist: Update.
* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
Likewise.
* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.
I noticed that there was no meaningful test coverage for
fegetexceptflag and fesetexceptflag (one test ensures that calls to
them compile and link, but nothing to verify they work correctly).
This patch adds tests for these functions.
fesetexceptflag is meant to set the relevant exception flag bits to
the saved state without causing enabled traps to be taken. On some
architectures, it is not possible to set exception flag bits without
causing enabled traps to occur. Such architectures need to define
EXCEPTION_SET_FORCES_TRAP to 1 in their math-tests.h, as is done in
this patch for powerpc. x86 avoids needing to define this because the
traps resulting from setting exception bits don't occur until the next
floating-point operation or fwait instruction.
Tested for x86_64, x86 and powerpc. Note that test-fexcept fails for
powerpc because of a pre-existing bug in fesetexceptflag for powerpc,
which I'll fix separately.
* math/test-fexcept-traps.c: New file.
* math/test-fexcept.c: Likewise.
* math/Makefile (tests): Add test-fexcept and test-fexcept-traps.
* sysdeps/generic/math-tests.h (EXCEPTION_SET_FORCES_TRAP): New
macro.
* sysdeps/powerpc/math-tests.h [!__NO_FPRS__]
(EXCEPTION_SET_FORCES_TRAP): Likewise.
