Add more IEEE half conversion routines:
- Convert 32-bit/64-bit integer to IEEE half.
- Convert IEEE half to 32-bit/64-bit integer.
They are required by RISC-V _Float16 support, tested with RISC-V GCC.
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.
I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah. I don't
know why I run into these diagnostics whereas others evidently do not.
remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date. Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.
Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions. These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.
The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively. These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:
https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dchttps://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
Here only add the implementation when building the RV32 port.
These macros are used when the following situations occur at the same
time: soft-fp fma, ldbl-128 and 32-bit _FP_W_TYPE_SIZE. The RISC-V
32-bit port is the first port which use all three together.
This is the building flow about the situation:
When building soft-fp/s_fmal.c, there uses the FP_FMA_Q in __fmal.
The _FP_W_TYPE_SIZE is defined to 32-bit in sysdeps/riscv/sfp-machine.h,
so the FP_FMA_Q was defined to _FP_FMA (Q, 4, 8, R, X, Y, Z) in
soft-fp/quad.h.
Something in the soft-fp/quad.h:
#if _FP_W_TYPE_SIZE < 64
# define FP_FMA_Q(R, X, Y, Z) _FP_FMA (Q, 4, 8, R, X, Y, Z)
#else
# define FP_FMA_Q(R, X, Y, Z) _FP_FMA (Q, 2, 4, R, X, Y, Z)
#endif
Finally, in _FP_FMA (fs, wc, dwc, R, X, Y, Z), it will use the
_FP_FRAC_HIGHBIT_DW_##dwc macro, and it will be expanded to
_FP_FRAC_HIGHBIT_DW_8, but the _FP_FRAC_HIGHBIT_DW_8 is not be
implemented in soft-fp/op-8.h. there is only _FP_FRAC_HIGHBIT_DW_1,
_FP_FRAC_HIGHBIT_DW_2 and _FP_FRAC_HIGHBIT_DW_4 in the
soft-fp/op-*.h.
After this modification, we can pass the soft floating testing of glibc
testsuites on RV32.
* soft-fp/op-8.h (_FP_FRAC_SET_8, _FP_FRAC_ADD_8, _FP_FRAC_SUB_8)
(_FP_FRAC_CLZ_8, _FP_MINFRAC_8, _FP_FRAC_NEGP_8, _FP_FRAC_ZEROP_8)
(_FP_FRAC_HIGHBIT_DW_8, _FP_FRAC_COPY_4_8, _FP_FRAC_COPY_8_4)
(__FP_FRAC_SET_8): Add implementation for RV32 use.
In FRAC_SUB_3(R, X, Y) and FRAC_SUB_4(R,, X, Y), it reference both
the X[N] and X[N] after R[N] have been set. If one of the X and Y is
the same address with R, the result of the calculation is wrong,
because the value of the original X and Y are overwritten.
In glibc, there are two places use FRAC_SUB and occurs the overlap.
The first is _FP_DIV_MEAT_N_loop in op-common.h, it uses the source
_FP_DIV_MEAT_N_loop_u as the destination. This macro only be used
when N is one(_FP_DIV_MEAT_1_loop) and then the _FP_FRAC_SUB_##wc
extend to _FP_FRAC_SUB_1 in this macro. so it also work because
_FP_FRAC_SUB_1 has no overlap problem in its implementation.
The second places is _FP_DIV_MEAT_4_udiv, the original value of X##_f[0]
is overwritten before the calculatation.
In FRAC_SUB_1 and FRAC_SUB_2, there don't refer the source after
destination have been set, so they have no problem.
After this modification, we can pass the soft floating testing of glibc
testsuites on RV32.
* soft-fp/op-4.h (_FP_FRAC_SUB_3, _FP_FRAC_SUB_4): Use temporary
variable to avoid overlap arguments.
powerpc-nofpu libc exports __sqrtsf2 and __sqrtdf2 symbols. The
export of these soft-fp symbols is a mistake; they aren't part of the
libgcc interface and GCC will never generate code that calls them.
This patch makes them into compat symbols (no code built for static
libc), moving their sources from the generic soft-fp sources to
sysdeps/powerpc/nofpu (the underlying soft-fp FP_SQRT functionality
remains of use to implement actual sqrt public interfaces, such as
sqrtl / sqrtf128 for which it is used on various platforms, but
__sqrt[sdt]f2 are not such interfaces).
Tested with build-many-glibcs.py for relevant platforms.
[BZ #18473]
* soft-fp/sqrttf2.c: Remove file.
* soft-fp/sqrtdf2.c: Move to ....
* sysdeps/powerpc/nofpu/sqrtdf2.c: ... here. Include
<shlib-compat.h>.
(__sqrtdf2): Make conditional on
[SHLIB_COMPAT (libc, GLIBC_2_3_2, GLIBC_2_28)]. Define as compat
symbol.
* soft-fp/sqrtsf2.c: Move to ....
* sysdeps/powerpc/nofpu/sqrtsf2.c: ... here. Include
<shlib-compat.h>.
(__sqrtsf2): Make conditional on
[SHLIB_COMPAT (libc, GLIBC_2_3_2, GLIBC_2_28)]. Define as compat
symbol.
* soft-fp/Makefile (gcc-single-routines): Remove sqrtsf2.
(gcc-double-routines): Remove sqrtdf2.
(gcc-quad-routines): Remove sqrttf2.
* sysdeps/nios2/Makefile [$(subdir) = soft-fp] (sysdep_routines):
Do not filter out sqrtsf2 and sqrtdf2.
* sysdeps/powerpc/nofpu/Makefile [$(subdir) = soft-fp]
(sysdep_routines): Add sqrtsf2 and sqrtdf2.
Building for soft-float ColdFire produces an error in soft-fp:
In file included from ../sysdeps/ieee754/soft-fp/s_fmaf.c:42:
../soft-fp/single.h:85:3: error: 'packed' attribute ignored for field of type 'struct <anonymous>' [-Werror=attributes]
} bits __attribute__ ((packed));
^
While this error only appears in that particular case, this attribute
is in fact never useful, on any architecture. If you have
struct __attribute__ ((packed)) { ... } bits;
or
struct { ... } __attribute__ ((packed)) bits;
then the attribute affects the layout of the structure type. But with
the form used in this code
struct { ... } bits __attribute__ ((packed));
the field bits is being declared packed, but the layout of its type
has already been determined at that point. If on any platform the
layout of the sequence of bit-fields were wrong without the use of a
packed attribute, the attribute would need to be used via a definition
of _FP_STRUCT_LAYOUT, not in its present position.
So this patch removes the useless attribute to fix the build for
ColdFire soft-float. Tested with build-many-glibcs.py that installed
stripped shared libraries are unchanged by the patch.
* soft-fp/double.h (union _FP_UNION_D): Do not use attribute
packed on bits.
* soft-fp/extended.h (union _FP_UNION_E): Likewise.
* soft-fp/half.h (union _FP_UNION_H): Likewise.
* soft-fp/quad.h (union _FP_UNION_Q): Likewise.
* soft-fp/single.h (union _FP_UNION_S): Likewise.
The default sysdeps/ieee754 fma implementations rely on exceptions and
rounding modes to achieve correct results through internal use of
round-to-odd. Thus, glibc configurations without support for
exceptions and rounding modes instead need to use implementations of
fma based on soft-fp.
At present, this is achieved via having implementation files in
soft-fp/ that are #included by sysdeps files for each glibc
configuration that needs them. In general this means such a
configuration has its own s_fma.c and s_fmaf.c.
TS 18661-1 adds functions that do an operation (+ - * / sqrt fma) on
arguments wider than the return type, with a single rounding of the
infinite-precision result to that return type. These are also
naturally implemented using round-to-odd on platforms with hardware
support for rounding modes and exceptions but lacking hardware support
for these narrowing operations themselves. (Platforms that have
direct hardware support for such narrowing operations include at least
ia64, and Power ISA 2.07 or later, which I think means POWER8 or
later.)
So adding the remaining TS 18661-1 functions would mean at least six
narrowing function implementations (fadd fsub fmul fdiv ffma fsqrt),
with aliases for other types and further implementations in some
configurations, that need to be overridden for configurations lacking
hardware exceptions and rounding modes. Requiring all such
configurations (currently seven of them) to have their own source
files for all those functions seems undesirable.
Thus, this patch adds a directory sysdeps/ieee754/soft-fp to contain
libm function implementations based on soft-fp. This directory is
then used via Implies from all the configurations that need it, so no
more files need adding to every such configuration when adding more
functions with soft-fp implementations. A configuration can still
selectively #include a particular file from this directory if desired;
thus, the MIPS #include of the fmal implementation is retained, since
that's appropriate even for hard float (because long double is always
implementated in software for MIPS64, so the soft-fp implementation of
fmal is better than the ldbl-128 one).
This also provides additional motivation for my recent patch removing
--with-fp / --without-fp: previously there was no need for correct use
of --without-fp for no-FPU ARM or SH3, and now we have autodetection
nofpu/ sysdeps directories can be used by this patch for those
configurations without imposing any new requirements on how glibc is
configured.
(The mips64/*/fpu/s_fma.c files added by this patch are needed to keep
the dbl-64 version of fma for double, rather than the ldbl-128 one,
used in that case.)
Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by this patch.
* soft-fp/fmadf4.c: Move to ....
* sysdeps/ieee754/soft-fp/s_fma.c: ... here.
* soft-fp/fmasf4.c: Move to ....
* sysdeps/ieee754/soft-fp/s_fmaf.c: ... here.
* soft-fp/fmatf4.c: Move to ....
* sysdeps/ieee754/soft-fp/s_fmal.c: ... here.
* sysdeps/ieee754/soft-fp/Makefile: New file.
* sysdeps/arm/preconfigure.ac: Define with_fp_cond.
* sysdeps/arm/preconfigure: Regenerated.
* sysdeps/arm/nofpu/Implies: New file.
* sysdeps/arm/s_fma.c: Remove file.
* sysdeps/arm/s_fmaf.c: Likewise.
* sysdeps/m68k/coldfire/nofpu/Implies: New file.
* sysdeps/m68k/coldfire/nofpu/s_fma.c: Remove file.
* sysdeps/m68k/coldfire/nofpu/s_fmaf.c: Likewise.
* sysdeps/microblaze/Implies: Add ieee754/soft-fp.
* sysdeps/microblaze/s_fma.c: Remove file.
* sysdeps/microblaze/s_fmaf.c: Likewise.
* sysdeps/mips/mips32/nofpu/Implies: New file.
* sysdeps/mips/mips64/n32/fpu/s_fma.c: Likewise.
* sysdeps/mips/mips64/n32/nofpu/Implies: Likewise.
* sysdeps/mips/mips64/n64/fpu/s_fma.c: Likewise.
* sysdeps/mips/mips64/n64/nofpu/Implies: Likewise.
* sysdeps/mips/ieee754/s_fma.c: Remove file.
* sysdeps/mips/ieee754/s_fmaf.c: Likewise.
* sysdeps/mips/ieee754/s_fmal.c: Update include for move of fmal
implementation.
* sysdeps/nios2/Implies: Add ieee754/soft-fp.
* sysdeps/nios2/s_fma.c: Remove file.
* sysdeps/nios2/s_fmaf.c: Likewise.
* sysdeps/sh/nofpu/Implies: New file.
* sysdeps/sh/s_fma.c: Remove file.
* sysdeps/sh/s_fmaf.c: Likewise.
* sysdeps/tile/Implies: Add ieee754/soft-fp.
* sysdeps/tile/s_fma.c: Remove file.
* sysdeps/tile/s_fmaf.c: Likewise.
This patch makes the soft-fp implementations of fma functions use the
libm_alias_* macros.
Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by the patch.
* soft-fp/fmadf4.c: Include <libm-alias-double.h>.
[!__fma] (fma): Define using libm_alias_double.
* soft-fp/fmasf4.c: Include <libm-alias-float.h>.
[!__fmaf] (fmaf): Define using libm_alias_float.
* soft-fp/fmatf4.c: Include <libm-alias-ldouble.h>.
(fmal): Define using libm_alias_ldouble.
Various subdirectories of glibc include Banner files to put some text
in the output of executing libc.so.6, under "Available extensions".
Some of those subdirectories (e.g. crypt) may originally have been
add-ons (and so optional, so a particular glibc build might or might
not have included them), but except for libidn they aren't now (or if
only included in some builds, in the case of soft-fp, the inclusion
depends on the architecture for which glibc is configured rather than
having any glibc configuration for which it's an optional feature),
and it doesn't seem useful for the libc.so.6 output to call out a few
features like that.
This patch removes the non-add-on Banner files, updating contrib.texi
where they noted contributions not otherwise mentioned there.
Tested for x86_64.
* crypt/Banner: Remove file.
* nptl/Banner: Likewise.
* resolv/Banner: Likewise.
* soft-fp/Banner: Likewise.
* nptl/Makefile ($(objpfx)banner.h): Remove rule.
($(objpfx)version.d): Remove dependency on banner.h.
($(objpfx)version.os): Likewise.
* nptl/version.c (banner): Do not include banner.h.
* manual/contrib.texi: Update entries for Richard Henderson, Jakub
Jelinek and BIND code.
posix/wordexp-test.c used libc-internal.h for PTR_ALIGN_DOWN; similar
to what was done with libc-diag.h, I have split the definitions of
cast_to_integer, ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and PTR_ALIGN_DOWN
to a new header, libc-pointer-arith.h.
It then occurred to me that the remaining declarations in libc-internal.h
are mostly to do with early initialization, and probably most of the
files including it, even in the core code, don't need it anymore. Indeed,
only 19 files actually need what remains of libc-internal.h. 23 others
need libc-diag.h instead, and 12 need libc-pointer-arith.h instead.
No file needs more than one of them, and 16 don't need any of them!
So, with this patch, libc-internal.h stops including libc-diag.h as
well as losing the pointer arithmetic macros, and all including files
are adjusted.
* include/libc-pointer-arith.h: New file. Define
cast_to_integer, ALIGN_UP, ALIGN_DOWN, PTR_ALIGN_UP, and
PTR_ALIGN_DOWN here.
* include/libc-internal.h: Definitions of above macros
moved from here. Don't include libc-diag.h anymore either.
* posix/wordexp-test.c: Include stdint.h and libc-pointer-arith.h.
Don't include libc-internal.h.
* debug/pcprofile.c, elf/dl-tunables.c, elf/soinit.c, io/openat.c
* io/openat64.c, misc/ptrace.c, nptl/pthread_clock_gettime.c
* nptl/pthread_clock_settime.c, nptl/pthread_cond_common.c
* string/strcoll_l.c, sysdeps/nacl/brk.c
* sysdeps/unix/clock_settime.c
* sysdeps/unix/sysv/linux/i386/get_clockfreq.c
* sysdeps/unix/sysv/linux/ia64/get_clockfreq.c
* sysdeps/unix/sysv/linux/powerpc/get_clockfreq.c
* sysdeps/unix/sysv/linux/sparc/sparc64/get_clockfreq.c:
Don't include libc-internal.h.
* elf/get-dynamic-info.h, iconv/loop.c
* iconvdata/iso-2022-cn-ext.c, locale/weight.h, locale/weightwc.h
* misc/reboot.c, nis/nis_table.c, nptl_db/thread_dbP.h
* nscd/connections.c, resolv/res_send.c, soft-fp/fmadf4.c
* soft-fp/fmasf4.c, soft-fp/fmatf4.c, stdio-common/vfscanf.c
* sysdeps/ieee754/dbl-64/e_lgamma_r.c
* sysdeps/ieee754/dbl-64/k_rem_pio2.c
* sysdeps/ieee754/flt-32/e_lgammaf_r.c
* sysdeps/ieee754/flt-32/k_rem_pio2f.c
* sysdeps/ieee754/ldbl-128/k_tanl.c
* sysdeps/ieee754/ldbl-128ibm/k_tanl.c
* sysdeps/ieee754/ldbl-96/e_lgammal_r.c
* sysdeps/ieee754/ldbl-96/k_tanl.c, sysdeps/nptl/futex-internal.h:
Include libc-diag.h instead of libc-internal.h.
* elf/dl-load.c, elf/dl-reloc.c, locale/programs/locarchive.c
* nptl/nptl-init.c, string/strcspn.c, string/strspn.c
* malloc/malloc.c, sysdeps/i386/nptl/tls.h
* sysdeps/nacl/dl-map-segments.h, sysdeps/x86_64/atomic-machine.h
* sysdeps/unix/sysv/linux/spawni.c
* sysdeps/x86_64/nptl/tls.h:
Include libc-pointer-arith.h instead of libc-internal.h.
* elf/get-dynamic-info.h, sysdeps/nacl/dl-map-segments.h
* sysdeps/x86_64/atomic-machine.h:
Add multiple include guard.
This patch adds conversion routines required for _Float16 support in
AArch64.
These are one-step conversions to and from TImode and TFmode. We need
these on AArch64 regardless of presence of the ARMv8.2-A 16-bit
floating-point extensions.
In the patch, soft-fp/half.h is derived from soft-fp/single.h . The
conversion routines are derivatives of their respective SFmode
variants.
* soft-fp/extendhftf2.c: New.
* soft-fp/fixhfti.c: Likewise.
* soft-fp/fixunshfti.c: Likewise.
* soft-fp/floattihf.c: Likewise.
* soft-fp/floatuntihf.c: Likewise.
* soft-fp/half.h: Likewise.
* soft-fp/trunctfhf2.c: Likewise.
soft-fp unpacking for x86 "extended" fails to clear the implicit
mantissa high bit that is explicit in that format, resulting in
problems for operations that expect this bit to be clear in raw
unpacked values. Specifically, the code for this format is used only
for conversions to and from TFmode (__float128) in libgcc, where this
issue results in GCC bug 77265, extension of long double infinity to
__float128 wrongly produces a NaN.
This patch fixes this by always masking out the implicit bit on
unpacking, so that the results of unpacking meet the expectations of
the rest of the soft-fp code for a normal IEEE format.
Tested for x86_64 in libgcc in conjunction with a GCC testcase for
this issue (this code isn't used in glibc, only in libgcc).
* soft-fp/extended.h [_FP_W_TYPE_SIZE < 64] (FP_UNPACK_RAW_E):
Mask implicit bit out of unpacked value.
[_FP_W_TYPE_SIZE < 64] (FP_UNPACK_RAW_EP): Likewise.
[_FP_W_TYPE_SIZE >= 64] (FP_UNPACK_RAW_E): Likewise.
[_FP_W_TYPE_SIZE >= 64] (FP_UNPACK_RAW_EP): Likewise.
One common case of __GNUC_PREREQ (4, 7) conditionals is use of
diagnostic control pragmas for -Wmaybe-uninitialized, an option
introduced in GCC 4.7 where older GCC needed -Wuninitialized to be
controlled instead if the warning appeared with older GCC. This patch
removes such conditionals.
(There remain several older uses of -Wno-uninitialized in makefiles
that still need to be converted to diagnostic control pragmas if the
issue is still present with current sources and supported GCC
versions, and it's likely that in most cases those pragmas also will
end up controlling -Wmaybe-uninitialized.)
Tested for x86_64 and x86 (testsuite, and that installed stripped
shared libraries are unchanged by the patch, except for libresolv
since res_send.c contains assertions whose line numbers are changed by
the patch).
* resolv/res_send.c (send_vc) [__GNUC_PREREQ (4, 7)]: Make code
unconditional.
* soft-fp/fmadf4.c [__GNUC_PREREQ (4, 7)]: Likewise.
[!__GNUC_PREREQ (4, 7)]: Remove conditional code.
* soft-fp/fmasf4.c [__GNUC_PREREQ (4, 7)]: Make code
unconditional.
[!__GNUC_PREREQ (4, 7)]: Remove conditional code.
* soft-fp/fmatf4.c [__GNUC_PREREQ (4, 7)]: Make code
unconditional.
[!__GNUC_PREREQ (4, 7)]: Remove conditional code.
* stdlib/setenv.c
[((__GNUC__ << 16) + __GNUC_MINOR__) >= ((4 << 16) + 7)]: Make
code unconditional.
[!(((__GNUC__ << 16) + __GNUC_MINOR__) >= ((4 << 16) + 7))]:
Remove conditional code.
* sysdeps/ieee754/dbl-64/e_lgamma_r.c
(__ieee754_lgamma_r) [__GNUC_PREREQ (4, 7)]: Make code
unconditional.
(__ieee754_lgamma_r) [!__GNUC_PREREQ (4, 7)]: Remove conditional
code.
* sysdeps/ieee754/flt-32/e_lgammaf_r.c
(__ieee754_lgammaf_r) [__GNUC_PREREQ (4, 7)]: Make code
unconditional.
(__ieee754_lgammaf_r) [!__GNUC_PREREQ (4, 7)]: Remove conditional
code.
* sysdeps/ieee754/ldbl-128/k_tanl.c
(__kernel_tanl) [__GNUC_PREREQ (4, 7)]: Make code unconditional.
(__kernel_tanl) [!__GNUC_PREREQ (4, 7)]: Remove conditional code.
* sysdeps/ieee754/ldbl-128ibm/k_tanl.c
(__kernel_tanl) [__GNUC_PREREQ (4, 7)]: Make code unconditional.
(__kernel_tanl) [!__GNUC_PREREQ (4, 7)]: Remove conditional code.
* sysdeps/ieee754/ldbl-96/e_lgammal_r.c
(__ieee754_lgammal_r) [__GNUC_PREREQ (4, 7)]: Make code
unconditional.
(__ieee754_lgammal_r) [!__GNUC_PREREQ (4, 7)]: Remove conditional
code.
* sysdeps/ieee754/ldbl-96/k_tanl.c
(__kernel_tanl) [__GNUC_PREREQ (4, 7)]: Make code unconditional.
(__kernel_tanl) [!__GNUC_PREREQ (4, 7)]: Remove conditional code.
GCC 6 puts out warnings in a different location then GCC 5. Move the
DIAG macros so that the warnings are supressed for both compilers.
ChangeLog:
* soft-fp/fmasf4.c: Add include of sys/cdefs.h.
Move DIAG_PUSH_NEEDS_COMMENT, DIAG_IGNORE_NEEDS_COMMENT to front of
file, move DIAG_POP_NEEDS_COMMENT to end of file.
* soft-fp/fmadf4.c: Ditto.
* soft-fp/fmatf4.c: Ditto.
The soft-fp implementations of fma produce -Wuninitialized warnings
because, in the cases where the result is not a nonzero finite value,
the soft-fp does not set the exponent of the result since the (cooked)
packing will do so, but the compiler does not then see that the
exponent is always set in packing before it's used if it wasn't set
earlier. This patch uses DIAG_* macros to suppress those warnings.
Tested for mips64. (In fact this allows the mips64 build to complete
with the -Wno-uninitialized removed from math/Makefile, but more
cleanups are still needed in the ldbl-128ibm code for uninitialized
warnings there.)
* soft-fp/fmadf4.c: Include <libc-internal.h>.
(__fma): Ignore uninitialized warnings around packing.
* soft-fp/fmasf4.c: Include <libc-internal.h>.
(__fmaf): Ignore uninitialized warnings around packing.
* soft-fp/fmatf4.c: Include <libc-internal.h>.
(__fmal): Ignore uninitialized warnings around packing.
This patch makes soft-fp use static assertions in place of conditional
calls to abort, in places where there are checks for conditions (on
the types for which a macro is used) that the code is not prepared to
handle. The fallback definition of _FP_STATIC_ASSERT (for kernel use
only, as only relevant to compilers not supported for building glibc)
is as in misc/sys/cdefs.h.
This means that soft-fp only ever calls abort for _FP_UNREACHABLE
calls in builds with GCC versions before 4.5. Thus, there is no need
for an abort declaration or <stdlib.h> include, since the kernel code
handles defining abort as a macro itself - and so this avoids any need
for an __KERNEL__ condition on the abort declaration to avoid it
breaking with the kernel's macro definition. That is, this patch is
intended to make glibc's soft-fp code suitable for kernel use with no
kernel-local changes to the soft-fp code needed at all.
Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by the patch. One explicit <stdlib.h> include had to be
added to a file that was relying on the include from soft-fp.h.
* soft-fp/soft-fp.h (_FP_STATIC_ASSERT): New macro.
[_LIBC]: Do not include <stdlib.h>.
[!_LIBC] (abort): Remove declaration.
* soft-fp/op-2.h (_FP_MUL_MEAT_2_120_240_double): Use
_FP_STATIC_ASSERT instead of conditionally calling abort.
* soft-fp/op-common.h (_FP_FROM_INT): Likewise.
(_FP_EXTEND_CNAN): Likewise.
(FP_TRUNC): Likewise.
(__FP_CLZ): Likewise.
* sysdeps/powerpc/nofpu/flt-rounds.c: Include <stdlib.h>.
This patch makes soft-fp use a new macro _FP_UNREACHABLE in place of
calling abort in unreachable default cases of switch statements.
_FP_UNREACHABLE expands to call __builtin_unreachable for GCC 4.5 and
later; the fallback to abort is thus only for kernel use.
Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch. Also tested with the math/ tests for mips64
(in the case of fma there *was* previously an abort call generated,
unlike for the other operations - one switch only deals with a subset
of classes for one operand based on what could have been generated in
the earlier part of fma, whereas the other switches deal with all
combinations of two classes - and this is apparently too complicated
for the default case to have been optimized away).
* soft-fp/soft-fp.h (_FP_UNREACHABLE): New macro.
* soft-fp/op-common.h (_FP_MUL): Use _FP_UNREACHABLE instead of
abort.
(_FP_FMA): Likewise.
(_FP_DIV): Likewise.
This patch makes soft-fp headers consistently use multiple-include
guards, something previously done mainly only in the Linux kernel
version. The guard macros aren't the same as those used in the Linux
kernel, but there seems to be enough variation in such guards in Linux
kernel code that hopefully this version will be acceptable there.
Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch.
* soft-fp/double.h [SOFT_FP_DOUBLE_H]: New multiple-include guard.
* soft-fp/extended.h [SOFT_FP_EXTENDED_H]: Likewise.
* soft-fp/op-1.h [SOFT_FP_OP_1_H]: Likewise.
* soft-fp/op-2.h [SOFT_FP_OP_2_H]: Likewise.
* soft-fp/op-4.h [SOFT_FP_OP_4_H]: Likewise.
* soft-fp/op-8.h [SOFT_FP_OP_8_H]: Likewise.
* soft-fp/op-common.h [SOFT_FP_OP_COMMON_H]: Likewise.
* soft-fp/quad.h [SOFT_FP_QUAD_H]: Likewise.
* soft-fp/single.h [SOFT_FP_SINGLE_H]: Likewise.
* soft-fp/soft-fp.h (SOFT_FP_H): Define to 1 rather than empty.
Add comment on closing #endif.
In the Linux kernel, some architectures have a single function that
uses different kinds of unpacking and packing depending on the
instruction being emulated, meaning it is not readily visible to the
compiler that variables from _FP_DECL and _FP_FRAC_DECL_* macros are
only used in cases where they were initialized. The existing copy of
soft-fp in the Linux kernel uses zero-initialization to avoid warnings
in this case, so while frowned upon as a warning suppression mechanism
in code built for glibc it seems appropriate to have such
zero-initialization conditional on __KERNEL__. This patch duly adds
it, via a macro _FP_ZERO_INIT that expands to empty for non-kernel
compilations.
Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch.
* soft-fp/soft-fp.h (_FP_ZERO_INIT): New macro. Define depending
on [__KERNEL__].
* soft-fp/op-1.h (_FP_FRAC_DECL_1): Use _FP_ZERO_INIT.
* soft-fp/op-2.h (_FP_FRAC_DECL_2): Likewise.
* soft-fp/op-common.h (_FP_DECL): Likewise.
My Linux kernel patch to update the kernel to current glibc soft-fp
<https://sourceware.org/ml/libc-alpha/2015-02/msg00107.html> still
leaves a few small differences between the two copies of soft-fp.
I think it's desirable to avoid such differences completely if
possible by having one set of sources suitable for use in both places.
To that end, this patch introduces a conditional on __KERNEL__ for the
path by which sfp-machine.h is included.
Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch.
* soft-fp/soft-fp.h [!_LIBC && __KERNEL__]: Include
<asm/sfp-machine.h> instead of <sfp-machine.h>.
soft-fp calls abort in various cases that the code doesn't handle, all
cases that should never actually occur for any supported choice of
types.
Calling an abort function is not appropriate for kernel use, so the
Linux kernel redefines abort as a macro in various ways in the ports
using this code, typically to "return 0" or similar.
One use of abort in soft-fp is inside a comma expression and doesn't
work with such a macro. This patch changes it to use a statement
expression.
Tested for powerpc-nofpu that installed shared libraries are unchanged
by this patch.
(There are two classes of aborts: those to make control flow visible
to the compiler, in default cases of switches over _FP_CLS_COMBINE,
which could reasonably change to __builtin_unreachable for glibc but
would still need to handle pre-4.5 compilers for kernel use, and those
intended to detect any use of soft-fp for combinations of types the
code doesn't know how to handle, which could reasonably become link
failures if the calls should always be optimized away. But those are
separate possible future enhancements.)
* soft-fp/op-common.h (_FP_FROM_INT): Wrap call to abort in
expression inside statement expression.
soft-fp's _FP_FMA fails to set the result's exponent for cases where
the result of the multiplication is 0, yielding incorrect (arbitrary,
depending on uninitialized values) results for those cases. This
affects libm for architectures using soft-fp to implement fma. This
patch adds the exponent setting and tests for this case.
Tested for ARM soft-float (which uses soft-fp fma), x86_64 and x86 (to
verify not introducing new libm test failures there).
(This bug showed up in testing my patch to move the Linux kernel to
current soft-fp. math/Makefile has "override CFLAGS +=
-Wno-uninitialized" which would have stopped compiler warnings from
showing up this problem, although I wouldn't be surprised if removing
that shows spurious warnings from this code, if the compiler fails to
follow that various cases where the exponent is uninitialized don't
need it initialized because the class is set to a value meaning the
uninitialized exponent isn't used.)
[BZ #17932]
* soft-fp/op-common.h (_FP_FMA): Set exponent of result in case
where multiplication results in zero and third argument is finite
and nonzero.
* math/auto-libm-test-in: Add more tests of fma.
* math/auto-libm-test-out: Regenerated.
In <https://sourceware.org/ml/libc-alpha/2014-09/msg00488.html>, I
noted that comparisons in soft-fp did not set FP_EX_DENORM unless
denormal operands were flushed to zero.
This patch fixes soft-fp to check for denormal operands for
comparisons and set that exception whenever FP_EX_DENORM is not zero.
In particular, for the one architecture for which the Linux kernel
defines FP_EX_DENORM (alpha), this corresponds to the existing logic
for comparisons and so allows that logic to be replaced by a simple
call to FP_CMP_D when soft-fp is updated in the kernel.
Tested for powerpc (e500) that installed stripped shared libraries are
unchanged by this patch.
* soft-fp/op-common.h (_FP_CMP_CHECK_DENORM): New macro.
(_FP_CMP_CHECK_FLUSH_ZERO): Likewise.
(_FP_CMP): Use_FP_CMP_CHECK_DENORM and _FP_CMP_CHECK_FLUSH_ZERO.
(_FP_CMP_EQ): Likewise.
(_FP_CMP_UNORD): Use _FP_CMP_CHECK_DENORM.
One special case needed in soft-fp to replace the old version in the
Linux kernel is extending from a narrower floating-point format to a
wider one without quieting signaling NaNs. (This is for
arch/powerpc/math-emu/lfs.c, where previously it used the old FP_CONV
which didn't do anything special for NaNs, then handled packing
specially for NaNs to avoid quieting at packing time, and discarded
the exceptions from unpacking.)
This patch accordingly refactors FP_EXTEND, creating a separate
_FP_EXTEND_CNAN that offers a choice of how NaNs are handled, with
FP_EXTEND reimplemented as a wrapper that provides the common case of
the IEEE operation that does quiet signaling NaNs and raise exceptions
for them.
Tested for powerpc (e500) that installed stripped shared libraries are
unchanged by this patch.
* soft-fp/op-common.h (FP_EXTEND): Rename to _FP_EXTEND_CNAN with
extra argument CHECK_NAN. Redefine as wrapper around
_FP_EXTEND_CNAN.
soft-fp has various macros containing labels and goto statements.
Because label names are function-scoped, this is problematic for using
the same macro more than once within a function, which some
architectures do in the Linux kernel (the soft-fp version there
predates the addition of any of these labels and gotos). This patch
fixes this by using __label__ to make the labels local to the block
with the __label__ declaration.
Tested for powerpc-nofpu that installed stripped shared libraries are
unchanged by this patch.
* soft-fp/op-common.h (_FP_ADD_INTERNAL): Declare labels with
__label__.
(_FP_FMA): Likewise.
(_FP_TO_INT_ROUND): Likewise.
(_FP_FROM_INT): Likewise.
Continuing the series of patches adding soft-fp features from the
kernel version of soft-fp to glibc so that glibc's version is able to
replace the old fork of soft-fp in the kernel, this patch adds the
last major such feature: _FP_TO_INT_ROUND, converting a floating-point
number to an integer with rounding according to the current rounding
direction (as opposed to truncating towards zero, which _FP_TO_INT
does).
The general structure of the implementation follows that of
_FP_TO_INT, but of course is more complicated. As with glibc's
_FP_TO_INT it works with raw input (the kernel versions of these
macros predate the conversion of _FP_TO_INT and many other macros to
raw or semi-raw input). I have not tried to work out what bugs there
might be in the kernel version that this might fix; it's a
from-scratch implementation based on _FP_TO_INT.
Tested for powerpc (soft-float) that there is no change to the
installed shared libraries; also tested with the libm tests with lrint
/ lrintf / llrint / llrintf made to use _FP_TO_INT_ROUND, to provide
some test of the functionality. As we don't have benchmarks for those
functions, I haven't actually included the soft-fp versions of them,
although I expect them to be faster than the existing code (given that
the existing code involves adding and subtracting numbers such as
0x1p52 to achieve the desired rounding, which is not particularly
efficient when the underlying floating point is software floating
point).
2014-11-04 Joseph Myers <joseph@codesourcery.com>
* soft-fp/op-common.h (_FP_TO_INT_ROUND): New macro.
* soft-fp/double.h [_FP_W_TYPE_SIZE < 64] (FP_TO_INT_ROUND_D): New
macro.
[_FP_W_TYPE_SIZE >= 64] (FP_TO_INT_ROUND_D): Likewise.
* soft-fp/extended.h [_FP_W_TYPE_SIZE < 64] (FP_TO_INT_ROUND_E):
New macro.
[_FP_W_TYPE_SIZE >= 64] (FP_TO_INT_ROUND_E): Likewise.
* soft-fp/quad.h [_FP_W_TYPE_SIZE < 64] (FP_TO_INT_ROUND_Q): New
macro.
[_FP_W_TYPE_SIZE >= 64] (FP_TO_INT_ROUND_Q): Likewise.
* soft-fp/single.h (FP_TO_INT_ROUND_S): New macro.
Continuing the addition of soft-fp features in the Linux kernel
version, this patch adds _FP_TO_INT support for rsigned == 2 (reduce
overflowing results modulo 2^rsize to fit in the destination, used for
alpha emulation).
The kernel version is buggy; it can left shift by a negative amount
when right shifting is required in an overflow case (the kernel
version also has other bugs fixed long ago in glibc; at least,
spurious exceptions converting to the most negative integer). This
version avoids that by handling overflow (other than to 0) for rsigned
== 2 along with the normal non-overflow case, which already properly
determines the direction in which to shift.
Tested for powerpc-nofpu. Some functions get slightly bigger and some
get slightly smaller, no doubt as a result of the change to where in
the macro "inexact" is raised, but I don't think those changes are
significant. Also tested for powerpc-nofpu with the relevant __fix*
functions changed to use rsigned == 2 (which is after all just as
valid as rsigned == 1 in IEEE terms), including verifying the results
and exceptions for various cases of conversions.
With these seven patches, the one remaining feature to add for the
soft-fp code to have all the features of the kernel version is
_FP_TO_INT_ROUND.
* soft-fp/op-common.h (_FP_TO_INT): Handle rsigned == 2.
As previously discussed
<https://sourceware.org/ml/libc-alpha/2013-10/msg00345.html>, it would
be desirable to be able to use the same version of the soft-fp code in
the Linux kernel as well as in glibc and libgcc (instead of an old
version in the kernel that's missing ten years of bug fixes,
performance improvements and new features), and to that end it is
useful to add to glibc's copy features in the kernel's copy, even when
they are not directly useful in glibc.
To that end, this patch adds one of those features: support for more
precise "invalid" exceptions describing the particular kind of invalid
operation. These are relevant for powerpc emulation, and are also as
described in IEEE 754-2008 as sub-exceptions.
The set of sub-exceptions here is the union of those supported on
powerpc and those from IEEE 754-2008 (the former adds a distinction
between 0/0 and Inf/Inf; the latter adds a distinction between Inf*0
from multiplication and the same from fma). This includes
sub-exceptions for sqrt, conversions to integer and comparisons that
are not supported in the kernel; I see no obvious reason for these
being missing from the kernel support, given that they are supported
on powerpc so accurate powerpc emulation should generate them.
Tested for powerpc-nofpu that the disassembly of installed shared
libraries is unchanged by this patch.
* soft-fp/soft-fp.h (FP_EX_INVALID_SNAN): New macro.
(FP_EX_INVALID_IMZ): Likewise.
(FP_EX_INVALID_IMZ_FMA): Likewise.
(FP_EX_INVALID_ISI): Likewise.
(FP_EX_INVALID_ZDZ): Likewise.
(FP_EX_INVALID_IDI): Likewise.
(FP_EX_INVALID_SQRT): Likewise.
(FP_EX_INVALID_CVI): Likewise.
(FP_EX_INVALID_VC): Likewise.
* soft-fp/op-common.h (_FP_UNPACK_CANONICAL): Specify more precise
"invalid" exceptions.
(_FP_CHECK_SIGNAN_SEMIRAW): Likewise.
(_FP_ADD_INTERNAL): Likewise.
(_FP_MUL): Likewise.
(_FP_FMA): Likewise.
(_FP_DIV): Likewise.
(_FP_CMP_CHECK_NAN): Likewise.
(_FP_SQRT): Likewise.
(_FP_TO_INT): Likewise.
(FP_EXTEND): Likewise.
Continuing the addition of soft-fp features used in the Linux kernel,
this patch adds soft-fp support for FP_DENORM_ZERO (flushing input
subnormal operands to zero of the same sign).
There are some differences from the kernel version. In the kernel,
the "inexact" exception is set when flushing to zero. This does not
appear to match the documented semantics for either of the
architectures (alpha and sh) for which the kernel uses FP_DENORM_ZERO,
so this patch does not set "inexact" in this case. More operations
now use raw or semi-raw unpacking for optimization than did in the
ten-year-old soft-fp version in the kernel, so checks of
FP_DENORM_ZERO are inserted in those operations. They are also
inserted for comparisons (which already used raw unpacking in the old
version) as I believe that's the correct thing to do when input
subnormals are flushed to zero. They are *not* inserted for _FP_NEG.
(If any processors do flush input subnormals to zero for negation, or
otherwise vary from the rules implemented when FP_DENORM_ZERO is set,
further macros for sfp-machine.h to control this may need to be
added.)
Although the addition for comparisons will cause FP_EX_DENORM to be
set in this case, it still won't be set for comparisons involving
subnormals when not flushed to zero. It's quite possible that
accurate emulation of processors that have such an exception for
subnormal operands will require further changes relating to when
FP_EX_DENORM is set (in general, the support for things defined by
IEEE should be considered more reliable and mature than the support
for things outside the scope of IEEE floating point).
Although some processors also have a mode for abrupt underflow -
producing zeroes instead of output subnormals - there is no such mode
in the kernel's soft-fp, so no such mode is added to glibc's soft-fp
(although it could be if someone wanted to emulate such processor
support).
Tested for powerpc-nofpu that the disassembly of installed shared
libraries is unchanged by this patch.
* soft-fp/soft-fp.h (FP_DENORM_ZERO): New macro.
* soft-fp/op-common.h (_FP_UNPACK_CANONICAL): Check
FP_DENORM_ZERO.
(_FP_CHECK_FLUSH_ZERO): New macro.
(_FP_ADD_INTERNAL): Call _FP_CHECK_FLUSH_ZERO.
(_FP_CMP): Likewise.
(_FP_CMP_EQ): Likewise.
(_FP_TO_INT): Do not set inexact for subnormal arguments if
FP_DENORM_ZERO.
(FP_EXTEND): Call _FP_CHECK_FLUSH_ZERO.
(FP_TRUNC): Likewise.
This patch fixes a latent bug in _FP_TO_INT regarding handling of
arguments with maximum exponent (infinities and NaNs). If the maximum
exponent is below that calculated as an overflow threshold, such
values would incorrectly be treated as normal values for the purposes
of the conversion. This could not occur for any of the conversions
actually occurring in glibc, libgcc or the Linux kernel (the maximum
exponent for float is, just, big enough to ensure overflow for
unsigned __int128), but would apply if soft-fp were used for IEEE
binary16. Appropriate checks are inserted to ensure that the maximum
exponent is always treated as an overflowing exponent, and never as a
normal one.
Tested for powerpc-nofpu that the disassembly of installed shared
libraries is unchanged by this patch.
* soft-fp/op-common.h (_FP_TO_INT): Ensure maximum exponent is
treated as invalid conversion, not as normal exponent.
This patch refactors how soft-fp comparisons handle setting exceptions
for NaN operands, so that exceptions are set through the FP_CMP macros
rather than directly in the C files calling them.
The _FP_CMP* and FP_CMP* macros gain an extra argument to specify when
exceptions should be set, 0 for no exception setting (I'm not sure
this is actually needed - at least it's not needed for IEEE operations
in glibc / libgcc, but might be relevant in some cases for kernel
use), 1 for exceptions only for signaling NaNs and 2 for exceptions
for all NaNs. This argument is handled through _FP_CMP_CHECK_NAN,
newly called by the _FP_CMP* macros when a NaN is encountered. Calls
to these macros are updated, which eliminates all the existing
checking and exception setting in soft-fp *.c files in glibc.
Tested for powerpc-nofpu. (The __unord* functions have no code
changes; the __eq* / __ge* / __le* functions get slightly larger, but
I don't think that's significant.)
* soft-fp/op-common.h (_FP_CMP_CHECK_NAN): New macro.
(_FP_CMP): Add extra argument EX. Call _FP_CMP_CHECK_NAN.
(_FP_CMP_EQ): Likewise.
(_FP_CMP_UNORD): Likewise.
* soft-fp/double.h (FP_CMP_D): Add extra argument EX.
(FP_CMP_EQ_D): Likewise.
(FP_CMP_UNORD_D): Likewise.
* soft-fp/extended.h (FP_CMP_E): Likewise.
(FP_CMP_EQ_E): Likewise.
(FP_CMP_UNORD_E): Likewise.
* soft-fp/quad.h (FP_CMP_Q): Likewise.
(FP_CMP_EQ_Q): Likewise.
(FP_CMP_UNORD_Q): Likewise.
* soft-fp/single.h (FP_CMP_S): Likewise.
(FP_CMP_EQ_S): Likewise.
(FP_CMP_UNORD_S): Likewise.
* soft-fp/eqdf2.c (__eqdf2): Update call to FP_CMP_EQ_D.
* soft-fp/eqsf2.c (__eqsf2): Update call to FP_CMP_EQ_S.
* soft-fp/eqtf2.c (__eqtf2): Update call to FP_CMP_EQ_Q.
* soft-fp/gedf2.c (__gedf2): Update call to FP_CMP_D.
* soft-fp/gesf2.c (__gesf2): Update call to FP_CMP_S.
* soft-fp/getf2.c (__getf2): Update call to FP_CMP_Q.
* soft-fp/ledf2.c (__ledf2): Update call to FP_CMP_D.
* soft-fp/lesf2.c (__lesf2): Update call to FP_CMP_S.
* soft-fp/letf2.c (__letf2): Update call to FP_CMP_Q.
* soft-fp/unorddf2.c (__unorddf2): Update call to FP_CMP_UNORD_D.
* soft-fp/unordsf2.c (__unordsf2): Update call to FP_CMP_UNORD_S.
* soft-fp/unordtf2.c (__unordtf2): Update call to FP_CMP_UNORD_Q.
* sysdeps/alpha/soft-fp/ots_cmpe.c (internal_compare): Update call
to FP_CMP_Q.
* sysdeps/sparc/sparc32/soft-fp/q_cmp.c (_Q_cmp): Update call to
FP_CMP_Q.
* sysdeps/sparc/sparc32/soft-fp/q_cmpe.c (_Q_cmpe): Likewise.
* sysdeps/sparc/sparc32/soft-fp/q_feq.c (_Q_feq): Update call to
FP_CMP_EQ_Q.
* sysdeps/sparc/sparc32/soft-fp/q_fge.c (_Q_fge): Update call to
FP_CMP_Q.
* sysdeps/sparc/sparc32/soft-fp/q_fgt.c (_Q_fgt): Likewise.
* sysdeps/sparc/sparc32/soft-fp/q_fle.c (_Q_fle): Likewise.
* sysdeps/sparc/sparc32/soft-fp/q_flt.c (_Q_flt): Likewise.
* sysdeps/sparc/sparc32/soft-fp/q_fne.c (_Q_fne): Update call to
FP_CMP_EQ_Q.
* sysdeps/sparc/sparc64/soft-fp/qp_cmp.c (_Qp_cmp): Update call to
FP_CMP_Q.
* sysdeps/sparc/sparc64/soft-fp/qp_cmpe.c (_Qp_cmpe): Likewise.
* sysdeps/sparc/sparc64/soft-fp/qp_feq.c (_Qp_feq): Update call to
FP_CMP_EQ_Q.
* sysdeps/sparc/sparc64/soft-fp/qp_fge.c (_Qp_fge): Update call to
FP_CMP_Q.
* sysdeps/sparc/sparc64/soft-fp/qp_fgt.c (_Qp_fgt): Likewise.
* sysdeps/sparc/sparc64/soft-fp/qp_fle.c (_Qp_fle): Likewise.
* sysdeps/sparc/sparc64/soft-fp/qp_flt.c (_Qp_flt): Likewise.
* sysdeps/sparc/sparc64/soft-fp/qp_fne.c (_Qp_fne): Update call to
FP_CMP_EQ_Q.
This patch fixes a soft-fp corner case I previously noted in
<https://sourceware.org/ml/libc-alpha/2013-10/msg00349.html>: when
trapping on underflow is enabled, extensions of subnormals from XFmode
to TFmode need to signal underflow because the result is tiny (but
exact, so the underflow flag is not raised unless trapping is
enabled).
To avoid any excess initialization or tests for other cases of
floating-point extensions, a new FP_INIT_TRAPPING_EXCEPTIONS is added
that does the initialization required for this particular case (more
than FP_INIT_EXCEPTIONS, less than FP_INIT_ROUNDMODE, in general), and
FP_NO_EXACT_UNDERFLOW is added to stub out FP_TRAPPING_EXCEPTIONS
tests for those cases of extensions where the test would be dead code,
to avoid any uninitialized variable warnings.
As the relevant case only applies in libgcc, not to any use of soft-fp
in glibc, there is no bug report in Bugzilla and no non-default
definitions of FP_INIT_TRAPPING_EXCEPTIONS are added by the patch. A
testcase will be added to GCC as part of an update of soft-fp in
libgcc once this patch is in libc.
Tested for powerpc-nofpu that the disassembly of installed shared
libraries is unchanged by this patch. Bootstrapped GCC with updated
soft-fp with no regressions on x86_64-unknown-linux-gnu and verified
that a test of the relevant case passes where it failed before.
* soft-fp/op-common.h (FP_EXTEND): When a subnormal input produces
a subnormal result, set the underflow exception if trapping on
underflow is enabled.
* soft-fp/soft-fp.h (FP_INIT_TRAPPING_EXCEPTIONS): New macro.
(FP_INIT_EXCEPTIONS): Default to FP_INIT_TRAPPING_EXCEPTIONS.
[FP_NO_EXACT_UNDERFLOW] (FP_TRAPPING_EXCEPTIONS): Undefine and
redefine to 0.
* soft-fp/extenddftf2.c (FP_NO_EXACT_UNDERFLOW): Define.
* soft-fp/extendsfdf2.c (FP_NO_EXACT_UNDERFLOW): Likewise.
* soft-fp/extendsftf2.c (FP_NO_EXACT_UNDERFLOW): Likewise.
* soft-fp/extendxftf2.c (__extendxftf2): Use
FP_INIT_TRAPPING_EXCEPTIONS instead of FP_INIT_ROUNDMODE.
