1 Commits

Author	SHA1	Message	Date
Joseph Myers	d8742dd82f	Add narrowing add functions. ... This patch adds the narrowing add functions from TS 18661-1 to glibc's libm: fadd, faddl, daddl, f32addf64, f32addf32x, f32xaddf64 for all configurations; f32addf64x, f32addf128, f64addf64x, f64addf128, f32xaddf64x, f32xaddf128, f64xaddf128 for configurations with _Float64x and _Float128; __nldbl_daddl for ldbl-opt. As discussed for the build infrastructure patch, tgmath.h support is deliberately deferred, and FP_FAST_* macros are not applicable without optimized function implementations. Function implementations are added for all relevant pairs of formats (including certain cases of a format and itself where more than one type has that format). The main implementations use round-to-odd, or a trivial computation in the case where both formats are the same or where the wider format is IBM long double (in which case we don't attempt to be correctly rounding). The sysdeps/ieee754/soft-fp implementations use soft-fp, and are used automatically for configurations without exceptions and rounding modes by virtue of existing Implies files. As previously discussed, optimized versions for particular architectures are possible, but not included. i386 gets a special version of f32xaddf64 to avoid problems with double rounding (similar to the existing fdim version), since this function must round just once without an intermediate rounding to long double. (No such special version is needed for any other function, because the nontrivial functions use round-to-odd, which does the intermediate computation with the rounding mode set to round-to-zero, and double rounding is OK except in round-to-nearest mode, so is OK for that intermediate round-to-zero computation.) mul and div will need slightly different special versions for i386 (using round-to-odd on long double instead of precision control) because of the possibility of inexact intermediate results in the subnormal range for double. To reduce duplication among the different function implementations, math-narrow.h gets macros CHECK_NARROW_ADD, NARROW_ADD_ROUND_TO_ODD and NARROW_ADD_TRIVIAL. In the trivial cases and for any architecture-specific optimized implementations, the overhead of the errno setting might be significant, but I think that's best handled through compiler built-in functions rather than providing separate no-errno versions in glibc (and likewise there are no __*_finite entry points for these function provided, __*_finite effectively being no-errno versions at present in most cases). Tested for x86_64 and x86, with both GCC 6 and GCC 7. Tested for mips64 (all three ABIs, both hard and soft float) and powerpc with GCC 7. Tested with build-many-glibcs.py with both GCC 6 and GCC 7. * math/Makefile (libm-narrow-fns): Add add. (libm-test-funcs-narrow): Likewise. * math/Versions (GLIBC_2.28): Add narrowing add functions. * math/bits/mathcalls-narrow.h (add): Use __MATHCALL_NARROW . * math/gen-auto-libm-tests.c (test_functions): Add add. * math/math-narrow.h (CHECK_NARROW_ADD): New macro. (NARROW_ADD_ROUND_TO_ODD): Likewise. (NARROW_ADD_TRIVIAL): Likewise. * sysdeps/ieee754/float128/float128_private.h (__faddl): New macro. (__daddl): Likewise. * sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add fadd and dadd. (CFLAGS-nldbl-dadd.c): New variable. (CFLAGS-nldbl-fadd.c): Likewise. * sysdeps/ieee754/ldbl-opt/Versions (GLIBC_2.28): Add __nldbl_daddl. * sysdeps/ieee754/ldbl-opt/nldbl-compat.h (__nldbl_daddl): New prototype. * manual/arith.texi (Misc FP Arithmetic): Document fadd, faddl, daddl, fMaddfN, fMaddfNx, fMxaddfN and fMxaddfNx. * math/auto-libm-test-in: Add tests of add. * math/auto-libm-test-out-narrow-add: New generated file. * math/libm-test-narrow-add.inc: New file. * sysdeps/i386/fpu/s_f32xaddf64.c: Likewise. * sysdeps/ieee754/dbl-64/s_f32xaddf64.c: Likewise. * sysdeps/ieee754/dbl-64/s_fadd.c: Likewise. * sysdeps/ieee754/float128/s_f32addf128.c: Likewise. * sysdeps/ieee754/float128/s_f64addf128.c: Likewise. * sysdeps/ieee754/float128/s_f64xaddf128.c: Likewise. * sysdeps/ieee754/ldbl-128/s_daddl.c: Likewise. * sysdeps/ieee754/ldbl-128/s_f64xaddf128.c: Likewise. * sysdeps/ieee754/ldbl-128/s_faddl.c: Likewise. * sysdeps/ieee754/ldbl-128ibm/s_daddl.c: Likewise. * sysdeps/ieee754/ldbl-128ibm/s_faddl.c: Likewise. * sysdeps/ieee754/ldbl-96/s_daddl.c: Likewise. * sysdeps/ieee754/ldbl-96/s_faddl.c: Likewise. * sysdeps/ieee754/ldbl-opt/nldbl-dadd.c: Likewise. * sysdeps/ieee754/ldbl-opt/nldbl-fadd.c: Likewise. * sysdeps/ieee754/soft-fp/s_daddl.c: Likewise. * sysdeps/ieee754/soft-fp/s_fadd.c: Likewise. * sysdeps/ieee754/soft-fp/s_faddl.c: Likewise. * sysdeps/powerpc/fpu/libm-test-ulps: Update. * sysdeps/mach/hurd/i386/libm.abilist: Likewise. * 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/riscv/rv64/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/tilegx32/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.	2018-02-10 02:08:43 +00:00