This patch removes the target macro LIBGCC2_LONG_DOUBLE_TYPE_SIZE.
After recent changes, this macro was used in two ways in libgcc: to
determine the mode of long double in dfp-bit.h, and to determine
whether a particular mode has excess precision for use in complex
multiplication.
The former is concerned specifically with long double: it relates to
use of strtold for converting between decimal and binary floating
point. This is replaced by comparing __LDBL_MANT_DIG__ with the
appropriate __LIBGCC_*_MANT_DIG__ macro. The latter is replaced
__LIBGCC_*_EXCESS_PRECISION__ predefined macros.
Remarks:
* Comparing (__LDBL_MANT_DIG__ == __LIBGCC_XF_MANT_DIG__) is more
fragile than it looks; it's possible for XFmode to have 53-bit
mantissa (TARGET_96_ROUND_53_LONG_DOUBLE, on FreeBSD and
DragonFlyBSD 32-bit), in which case such a comparison would not
distinguish XFmode and DFmode as possible modes for long double.
Fortunately, no target supporting that form of XFmode also supports
long double = double (but if some target did, we'd need e.g. an
additional macro giving the exponent range of each mode).
Furthermore, this code doesn't actually get used for x86 (or any
other target with XFmode support), because x86 uses BID not DPD and
BID has its own conversion code (which handles conversions for both
XFmode and TFmode without needing to go via strtold). And FreeBSD
and DragonFlyBSD aren't among the targets with DFP support. So
while in principle this code is fragile and it's a deficiency that
it can't support both XFmode and TFmode at once (something that
can't be solved with the string conversion approach without libc
having TS 18661 functions such as strtof128), all these issues
should not be a problem in practice.
* If other cases of excess precision are supported in future, the code
for defining __LIBGCC_*_EXCESS_PRECISION__ may need updating.
Although the most likely such cases might not actually involve
excess precision for any mode used in libgcc - FLT_EVAL_METHOD being
32 to do _Float16 arithmetic on _Float32 should have the effect of
_Complex _Float16 arithmetic using __mulsc3 and __divsc3, rather
than currently nonexistent __mulhc3 and __divhc3 as in bug 63250 for
ARM.
* As has been noted in the context of simultaneous support for
__float128 and __ibm128 on Power, the semantics of macros such as
LONG_DOUBLE_TYPE_SIZE are problematic because they rely on a
poorly-defined precision value for floating-point modes (which seems
to be intended as the number of significant bits in the
representation, e.g. 80 for XFmode which may be either 12 or 16
bytes) uniquely identifying a mode (although defining an arbitrarily
different value for one of the modes you wish to distinguish may
work as a hack). It would be cleaner to have a target hook that
gives a machine mode directly for float, double and long double,
rather than going via these precision values. By eliminating all
use of these macros (FLOAT_TYPE_SIZE, DOUBLE_TYPE_SIZE,
LONG_DOUBLE_TYPE_SIZE) from code built for the target, this patch
facilitates such a conversion to a hook (which I suppose would take
some suitable enum as an argument to identify which of the three
types to return a mode for).
(The issue of multiple type support for DFP conversions would apply
in that Power case.
<https://gcc.gnu.org/ml/gcc-patches/2014-07/msg01084.html> doesn't
seem to touch on it, but it would seem reasonable to punt on it
initially as hard to fix. There would also be the issue of getting
functions such as __powikf2, __mulkc3, __divkc3 defined, but that's
rather easier to address.)
Bootstrapped with no regressions on x86_64-unknown-linux-gnu.
gcc:
* doc/tm.texi.in (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* doc/tm.texi: Regenerate.
* system.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Poison.
* config/alpha/alpha.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/i386/i386-interix.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE):
Remove.
* config/i386/i386.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/i386/rtemself.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/ia64/ia64.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/m68k/m68k.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/m68k/netbsd-elf.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE):
Remove.
* config/mips/mips.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/mips/n32-elf.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/msp430/msp430.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/rl78/rl78.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/rs6000/rs6000.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/rx/rx.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/s390/s390.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/sparc/freebsd.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/sparc/linux.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/sparc/linux64.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
* config/sparc/netbsd-elf.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE):
Remove.
gcc/c-family:
* c-cppbuiltin.c (c_cpp_builtins): Define
__LIBGCC_*_EXCESS_PRECISION__ macros for supported floating-point
modes.
libgcc:
* dfp-bit.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
(__LIBGCC_XF_MANT_DIG__): Define if not already defined.
(LONG_DOUBLE_HAS_XF_MODE): Define in terms of
__LIBGCC_XF_MANT_DIG__.
(__LIBGCC_TF_MANT_DIG__): Define if not already defined.
(LONG_DOUBLE_HAS_TF_MODE): Define in terms of
__LIBGCC_TF_MANT_DIG__.
* libgcc2.c (NOTRUNC): Define in terms of
__LIBGCC_*_EXCESS_PRECISION__, not LIBGCC2_LONG_DOUBLE_TYPE_SIZE.
* libgcc2.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Remove.
From-SVN: r215491
This patch removes the LIBGCC2_HAS_{SF,DF,XF,TF}_MODE target macros,
replacing them by predefines with -fbuilding-libgcc, together with a
target hook that can influence those predefines when needed.
The new default is that a floating-point mode is supported in libgcc
if (a) it passes the scalar_mode_supported_p hook (otherwise it's not
plausible for it to be supported in libgcc) and (b) it's one of those
four modes (since those are the modes for which libgcc hardcodes the
possibility of support). The target hook can override the default
choice (in either direction) for modes that pass
scalar_mode_supported_p (although overriding in the direction of
returning true when the default would return false only makes sense if
all relevant functions are specially defined in libgcc for that
particular target).
The previous default settings depended on various settings such as
LIBGCC2_LONG_DOUBLE_TYPE_SIZE, as well as targets defining the above
target macros if the default wasn't correct.
The default scalar_mode_supported_p only declares a floating-point
mode to be supported if it matches one of float / double / long
double. This means that in most cases where a mode is only supported
conditionally in libgcc (TFmode only supported if it's the mode of
long double, most commonly), the default gets things right. Overrides
were needed in the following cases:
* SFmode would always have been supported in libgcc (the condition was
BITS_PER_UNIT == 8, true for all current targets), but pdp11
defaults to 64-bit float, and in that case SFmode would fail
scalar_mode_supported_p. I don't know if libgcc actually built for
pdp11 (and the port may well no longer be being used), but this
patch adds a scalar_mode_supported_p hook to it to ensure SFmode is
treated as supported.
* Certain i386 and ia64 targets need the new hook to match the
existing cases for when XFmode or TFmode support is present in
libgcc. For i386, the hook can always declare XFmode to be
supported - the cases where it's not are the cases where long double
is TFmode, in which case XFmode fails scalar_mode_supported_p[*] -
but TFmode support needs to be conditional. (And of the targets not
defining LIBGCC2_HAS_TF_MODE before this patch, some defined
LONG_DOUBLE_TYPE_SIZE to 64, so ensuring LIBGCC2_HAS_TF_MODE would
always be false, while others did not define it, so allowing it to
be true in the -mlong-double-128 case. This patch matches that
logic, although I suspect all the latter targets would have been
broken if you tried to enable -mlong-double-128 by default, for lack
of the soft-fp TFmode support in libgcc, which is separately
configured.)
[*] I don't know if it's deliberate not to support __float80 at all
with -mlong-double-128.
In order to implement the default version of the new hook,
insn-modes.h was made to contain macros such as HAVE_TFmode for each
machine mode, so the default hook can contain conditionals on whether
XFmode and TFmode exist (to match the hardcoding of a list of modes in
libgcc). This is also used in fortran/trans-types.c; previously it
had a conditional on defined(LIBGCC2_HAS_TF_MODE) (a bit dubious,
since it ignored the value of the macro), which is replaced by testing
defined(HAVE_TFmode), in conjunction with requiring
targetm.libgcc_floating_mode_supported_p.
(Fortran is testing something stronger than that hook: not only is
libgcc support required, but also libm or equivalent. Thus, it has a
test for ENABLE_LIBQUADMATH_SUPPORT in the case that the mode is
TFmode and that's not the same as any of the three standard types.
The old and new tests are intended to accept exactly the same set of
modes for all targets.)
Apart from the four target macros eliminated by this patch, it gets us
closer to eliminating LIBGCC2_LONG_DOUBLE_TYPE_SIZE as well, though a
few more places using that macro need changing first.
Bootstrapped with no regressions on x86_64-unknown-linux-gnu; also
built cc1 for crosses to ia64-elf and pdp11-none as a minimal test of
changes for those targets.
gcc:
* target.def (libgcc_floating_mode_supported_p): New hook.
* targhooks.c (default_libgcc_floating_mode_supported_p): New
function.
* targhooks.h (default_libgcc_floating_mode_supported_p): Declare.
* doc/tm.texi.in (LIBGCC2_HAS_DF_MODE, LIBGCC2_HAS_XF_MODE)
(LIBGCC2_HAS_TF_MODE): Remove.
(TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P): New @hook.
* doc/tm.texi: Regenerate.
* genmodes.c (emit_insn_modes_h): Define HAVE_%smode for each
machine mode.
* system.h (LIBGCC2_HAS_SF_MODE, LIBGCC2_HAS_DF_MODE)
(LIBGCC2_HAS_XF_MODE, LIBGCC2_HAS_TF_MODE): Poison.
* config/i386/cygming.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/darwin.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/djgpp.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/dragonfly.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/freebsd.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/gnu-user-common.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/i386-interix.h (IX86_NO_LIBGCC_TFMODE): Define.
* config/i386/i386.c (ix86_libgcc_floating_mode_supported_p): New
function.
(TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P): Define.
* config/i386/i386elf.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/lynx.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/netbsd-elf.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/netbsd64.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/nto.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/openbsd.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/i386/openbsdelf.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/rtemself.h (IX86_NO_LIBGCC_TFMODE): Define.
* config/i386/sol2.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/i386/vx-common.h (IX86_MAYBE_NO_LIBGCC_TFMODE): Define.
* config/ia64/elf.h (IA64_NO_LIBGCC_TFMODE): Define.
* config/ia64/freebsd.h (IA64_NO_LIBGCC_TFMODE): Define.
* config/ia64/hpux.h (LIBGCC2_HAS_XF_MODE, LIBGCC2_HAS_TF_MODE):
Remove.
* config/ia64/ia64.c (TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P):
New macro.
(ia64_libgcc_floating_mode_supported_p): New function.
* config/ia64/linux.h (LIBGCC2_HAS_TF_MODE): Remove.
* config/ia64/vms.h (IA64_NO_LIBGCC_XFMODE)
(IA64_NO_LIBGCC_TFMODE): Define.
* config/msp430/msp430.h (LIBGCC2_HAS_DF_MODE): Remove.
* config/pdp11/pdp11.c (TARGET_SCALAR_MODE_SUPPORTED_P): New
macro.
(pdp11_scalar_mode_supported_p): New function.
* config/rl78/rl78.h (LIBGCC2_HAS_DF_MODE): Remove.
* config/rx/rx.h (LIBGCC2_HAS_DF_MODE): Remove.
gcc/c-family:
* c-cppbuiltin.c (c_cpp_builtins): Define __LIBGCC_HAS_%s_MODE__
macros for floating-point modes.
gcc/fortran:
* trans-types.c (gfc_init_kinds): Check
targetm.libgcc_floating_mode_supported_p for floating-point
modes. Check HAVE_TFmode instead of LIBGCC2_HAS_TF_MODE.
libgcc:
* libgcc2.h (LIBGCC2_HAS_SF_MODE): Define using
__LIBGCC_HAS_SF_MODE__.
(LIBGCC2_HAS_DF_MODE): Define using __LIBGCC_HAS_DF_MODE__.
(LIBGCC2_HAS_XF_MODE): Define using __LIBGCC_HAS_XF_MODE__.
(LIBGCC2_HAS_TF_MODE): Define using __LIBGCC_HAS_TF_MODE__.
* config/libbid/bid_gcc_intrinsics.h
(LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Do not define.
(LIBGCC2_HAS_XF_MODE): Define using __LIBGCC_HAS_XF_MODE__.
(LIBGCC2_HAS_TF_MODE): Define using __LIBGCC_HAS_TF_MODE__.
* fixed-bit.h (LIBGCC2_LONG_DOUBLE_TYPE_SIZE): Do not define.
(LIBGCC2_HAS_SF_MODE): Define using __LIBGCC_HAS_SF_MODE__.
(LIBGCC2_HAS_DF_MODE): Define using __LIBGCC_HAS_DF_MODE__.
From-SVN: r215215
gcc:
* config/i386/cygming.h (TF_SIZE): Remove.
* config/i386/darwin.h (TF_SIZE): Remove.
* config/i386/dragonfly.h (TF_SIZE): Remove.
* config/i386/freebsd.h (TF_SIZE): Remove.
* config/i386/gnu-user-common.h (TF_SIZE): Remove.
* config/i386/openbsdelf.h (TF_SIZE): Remove.
* config/i386/sol2.h (TF_SIZE): Remove.
* config/ia64/hpux.h (XF_SIZE, TF_SIZE): Remove.
* config/ia64/linux.h (TF_SIZE): Remove.
* doc/tm.texi.in (SF_SIZE, DF_SIZE, XF_SIZE, TF_SIZE): Remove.
* doc/tm.texi: Regenerate.
* system.h (SF_SIZE, DF_SIZE, XF_SIZE, TF_SIZE): Poison.
gcc/c-family:
* c-cppbuiltin.c (c_cpp_builtins): Define macros for mantissa
digits of floating-point modes if -fbuilding-libgcc.
libgcc:
* libgcc2.c (SF_SIZE): Change all uses to __LIBGCC_SF_MANT_DIG__.
(DF_SIZE): Change all uses to __LIBGCC_DF_MANT_DIG__.
(XF_SIZE): Change all uses to __LIBGCC_XF_MANT_DIG__.
(TF_SIZE): Change all uses to __LIBGCC_TF_MANT_DIG__.
* libgcc2.h (SF_SIZE): Change to __LIBGCC_SF_MANT_DIG__. Give
error if not defined and LIBGCC2_HAS_SF_MODE is defined.
(DF_SIZE): Change to __LIBGCC_DF_MANT_DIG__. Give error if not
defined and LIBGCC2_HAS_DF_MODE is defined.
(XF_SIZE): Change to __LIBGCC_XF_MANT_DIG__. Give error if not
defined and LIBGCC2_HAS_XF_MODE is defined.
(TF_SIZE): Change to __LIBGCC_TF_MANT_DIG__. Give error if not
defined and LIBGCC2_HAS_TF_MODE is defined.
From-SVN: r215014
Trevor Saunders
Jakub Jelinek
Joseph Myers
Richard Sandiford
Rainer Orth