gcc/libgcc/config/t-softfp
Jakub Jelinek 2ce182e258 libgcc _BitInt support [PR102989]
This patch adds the library helpers for multiplication, division + modulo
and casts from and to floating point (both binary and decimal).
As described in the intro, the first step is try to reduce further the
passed in precision by skipping over most significant limbs with just zeros
or sign bit copies.  For multiplication and division I've implemented
a simple algorithm, using something smarter like Karatsuba or Toom N-Way
might be faster for very large _BitInts (which we don't support right now
anyway), but could mean more code in libgcc, which maybe isn't what people
are willing to accept.
For the to/from floating point conversions the patch uses soft-fp, because
it already has tons of handy macros which can be used for that.  In theory
it could be implemented using {,unsigned} long long or {,unsigned} __int128
to/from floating point conversions with some frexp before/after, but at that
point we already need to force it into integer registers and analyze it
anyway.  Plus, for 32-bit arches there is no __int128 that could be used
for XF/TF mode stuff.
I know that soft-fp is owned by glibc and I think the op-common.h change
should be propagated there, but the bitint stuff is really GCC specific
and IMHO doesn't belong into the glibc copy.

2023-09-06  Jakub Jelinek  <jakub@redhat.com>

	PR c/102989
libgcc/
	* config/aarch64/t-softfp (softfp_extras): Use += rather than :=.
	* config/i386/64/t-softfp (softfp_extras): Likewise.
	* config/i386/libgcc-glibc.ver (GCC_14.0.0): Export _BitInt support
	routines.
	* config/i386/t-softfp (softfp_extras): Add fixxfbitint and
	bf, hf and xf mode floatbitint.
	(CFLAGS-floatbitintbf.c, CFLAGS-floatbitinthf.c): Add -msse2.
	* config/riscv/t-softfp32 (softfp_extras): Use += rather than :=.
	* config/rs6000/t-e500v1-fp (softfp_extras): Likewise.
	* config/rs6000/t-e500v2-fp (softfp_extras): Likewise.
	* config/t-softfp (softfp_floatbitint_funcs): New.
	(softfp_bid_list): New.
	(softfp_func_list): Add sf and df mode from and to _BitInt libcalls.
	(softfp_bid_file_list): New.
	(LIB2ADD_ST): Add $(softfp_bid_file_list).
	* config/t-softfp-sfdftf (softfp_extras): Add fixtfbitint and
	floatbitinttf.
	* config/t-softfp-tf (softfp_extras): Likewise.
	* libgcc2.c (bitint_reduce_prec): New inline function.
	(BITINT_INC, BITINT_END): Define.
	(bitint_mul_1, bitint_addmul_1): New helper functions.
	(__mulbitint3): New function.
	(bitint_negate, bitint_submul_1): New helper functions.
	(__divmodbitint4): New function.
	* libgcc2.h (LIBGCC2_UNITS_PER_WORD): When building _BitInt support
	libcalls, redefine depending on __LIBGCC_BITINT_LIMB_WIDTH__.
	(__mulbitint3, __divmodbitint4): Declare.
	* libgcc-std.ver.in (GCC_14.0.0): Export _BitInt support routines.
	* Makefile.in (lib2funcs): Add _mulbitint3.
	(LIB2_DIVMOD_FUNCS): Add _divmodbitint4.
	* soft-fp/bitint.h: New file.
	* soft-fp/fixdfbitint.c: New file.
	* soft-fp/fixsfbitint.c: New file.
	* soft-fp/fixtfbitint.c: New file.
	* soft-fp/fixxfbitint.c: New file.
	* soft-fp/floatbitintbf.c: New file.
	* soft-fp/floatbitintdf.c: New file.
	* soft-fp/floatbitinthf.c: New file.
	* soft-fp/floatbitintsf.c: New file.
	* soft-fp/floatbitinttf.c: New file.
	* soft-fp/floatbitintxf.c: New file.
	* soft-fp/op-common.h (_FP_FROM_INT): Add support for rsize up to
	4 * _FP_W_TYPE_SIZE rather than just 2 * _FP_W_TYPE_SIZE.
	* soft-fp/bitintpow10.c: New file.
	* soft-fp/fixsdbitint.c: New file.
	* soft-fp/fixddbitint.c: New file.
	* soft-fp/fixtdbitint.c: New file.
	* soft-fp/floatbitintsd.c: New file.
	* soft-fp/floatbitintdd.c: New file.
	* soft-fp/floatbitinttd.c: New file.
2023-09-06 17:33:05 +02:00

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# Copyright (C) 2006-2023 Free Software Foundation, Inc.
# This file is part of GCC.
# GCC is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3, or (at your option)
# any later version.
# GCC is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with GCC; see the file COPYING3. If not see
# <http://www.gnu.org/licenses/>.
# Targets using soft-fp should define the following variables:
#
# softfp_float_modes: a list of soft-float floating-point modes,
# e.g. sf df
# softfp_int_modes: a list of integer modes for which to define conversions,
# e.g. si di
# softfp_extensions: a list of extensions between floating-point modes,
# e.g. sfdf
# softfp_truncations: a list of truncations between floating-point modes,
# e.g. dfsf
#
# Extensions and truncations should include those where only one mode
# is a soft-float mode; for example, sftf where sf is hard-float and
# tf is soft-float.
#
# If some additional functions should be built that are not implied by
# the above settings, also define softfp_extras as a list of those
# functions, e.g. unorddf2.
#
# If the functions should only be built as compat symbols for shared
# libgcc, not available for new links, also define:
#
# softfp_compat := y
#
# If the libgcc2.c functions should not be replaced, also define:
#
# softfp_exclude_libgcc2 := y
#
# Avoiding replacing the libgcc2.c functions is a temporary measure
# for targets with both hard-float and soft-float multilibs, since
# these variables apply for all multilibs. With toplevel libgcc,
# soft-fp can be used conditionally on the multilib instead.
#
# If the code should not be compiled at all for some multilibs, define:
#
# softfp_wrap_start: text to put at the start of wrapper source files,
# output with echo
# e.g. '#ifndef __powerpc64__'
# softfp_wrap_end: text to put at the end of wrapper source files,
# e.g. '#endif'
#
# This is another temporary measure, and cannot be used together with
# softfp_compat.
softfp_float_funcs = add$(m)3 div$(m)3 eq$(m)2 ge$(m)2 le$(m)2 mul$(m)3 \
neg$(m)2 sub$(m)3 unord$(m)2
softfp_floatint_funcs = fix$(m)$(i) fixuns$(m)$(i) \
float$(i)$(m) floatun$(i)$(m)
softfp_floatbitint_funcs = fix$(m)bitint floatbitint$(m)
softfp_bid_list :=
ifeq ($(decimal_float),yes)
ifeq ($(enable_decimal_float),bid)
softfp_bid_list += bitintpow10 \
$(foreach m,sd dd td,fix$(m)bitint floatbitint$(m))
endif
endif
softfp_func_list := \
$(foreach m,$(softfp_float_modes), \
$(softfp_float_funcs) \
$(foreach i,$(softfp_int_modes), \
$(softfp_floatint_funcs))) \
$(foreach m,sf df,$(softfp_floatbitint_funcs)) \
$(foreach e,$(softfp_extensions),extend$(e)2) \
$(foreach t,$(softfp_truncations),trunc$(t)2) \
$(softfp_extras)
ifeq ($(softfp_exclude_libgcc2),y)
# This list is taken from mklibgcc.in and doesn't presently allow for
# 64-bit targets where si should become di and di should become ti.
softfp_func_list := $(filter-out floatdidf floatdisf fixunsdfsi fixunssfsi \
fixunsdfdi fixdfdi fixunssfdi fixsfdi fixxfdi fixunsxfdi \
floatdixf fixunsxfsi fixtfdi fixunstfdi floatditf \
floatundidf floatundisf floatundixf floatunditf,$(softfp_func_list))
endif
ifeq ($(softfp_compat),y)
softfp_file_list := $(addsuffix .c,$(softfp_func_list))
ifeq ($(enable_shared),yes)
softfp_map_dep := libgcc.map.in
else
softfp_map_dep :=
endif
softfp_set_symver = echo "asm (\".symver $(1),$(1)@`$(AWK) -f $(srcdir)/find-symver.awk -v symbol=$(1) libgcc.map.in`\");" >> $@
$(softfp_file_list): $(softfp_map_dep)
echo '#ifdef SHARED' > $@
echo '#include "soft-fp/$@"' >> $@
ifeq ($(enable_shared),yes)
$(call softfp_set_symver,__$(*F))
if grep strong_alias $(srcdir)/soft-fp/$@ > /dev/null; then \
alias=`grep strong_alias $(srcdir)/soft-fp/$@ | sed -e 's/.*, *//' -e 's/).*//'`; \
$(call softfp_set_symver,$$alias); \
fi
endif
echo '#endif' >> $@
else
ifneq ($(softfp_wrap_start),)
softfp_file_list := $(addsuffix .c,$(softfp_func_list))
$(softfp_file_list):
echo $(softfp_wrap_start) > $@
echo '#include "soft-fp/$@"' >> $@
echo $(softfp_wrap_end) >> $@
else
softfp_file_list := \
$(addsuffix .c,$(addprefix $(srcdir)/soft-fp/,$(softfp_func_list)))
endif
endif
softfp_bid_file_list := \
$(addsuffix .c,$(addprefix $(srcdir)/soft-fp/,$(softfp_bid_list)))
# Disable missing prototype and type limit warnings. The prototypes
# for the functions in the soft-fp files have not been brought across
# from glibc.
soft-fp-objects-base = $(basename $(notdir $(softfp_file_list)))
soft-fp-objects = $(addsuffix $(objext), $(soft-fp-objects-base)) \
$(addsuffix _s$(objext), $(soft-fp-objects-base))
$(soft-fp-objects) : INTERNAL_CFLAGS += -Wno-missing-prototypes -Wno-type-limits
LIB2ADD += $(softfp_file_list)
LIB2ADD_ST += $(softfp_bid_file_list)
ifneq ($(softfp_exclude_libgcc2),y)
# Functions in libgcc2.c are excluded for each soft-float mode (a
# target may have both soft-float and hard-float modes), for the fixed
# list of integer modes (si and di) for which libgcc2.c defines any
# such functions. Depending on the target, the si and di symbols may
# in fact define di and ti functions.
LIB2FUNCS_EXCLUDE += \
$(addprefix _,$(foreach m,$(softfp_float_modes), \
$(foreach i,si di, \
$(softfp_floatint_funcs))))
endif