On Mon, Oct 30, 2017 at 06:32:44PM +0000, Joseph Myers wrote:
> On Mon, 30 Oct 2017, Michael Meissner wrote:
>
> > > One obvious possible fix would be for the builtins.def macros never to
> > > define public names such as sqrtf128 for C++, only ever for C. That
> > > would
> > > be on the basis that C++ code is expected to be using a sqrt overload
> > > anyway - so making the built-in function available under a public name,
> > > in
> > > the case where __float128 exists for C++, is a matter for libstdc++
> > > headers.
> >
> > Arghh, yes, I can restrict it to just the C language. Would you prefer just
> > that? Do we want a target hook to be able to over-ride this on a platform
>
> Yes, I think such a restriction is appropriate (that is, C and ObjC get
> both sqrtf128 and __builtin_sqrtf128 built-in functions, C++ and ObjC++
> get only __builtin_sqrtf128).
>
> > basis (with the default behavior only enabling it for C)?
>
> If we think that the preferred way for C++ code to access the underlying
> functions is via function overloads for __float128 (not currently
> implemented in libstdc++, it seems) rather than suffixed functions, or
> through accessing the format as long double once that support is working,
> a target hook may not be neded. If C++ code is expected to use
> f128-suffixed functions directly, presumably it's desirable for a C++ call
> to sqrtf128 to be inlined where possible and so you'd want a hook, or some
> other way of enabling the built-in functions for C++ only in the case
> where they are usefully distinct from the float / double / long double
> functions.
This patch fixes exporting the non __builtin_ names to be done by default only
for the C language. I added a target hook in case a port needs to enable
built-ins for C++ (either wholesale, or for particular built-in functions).
I have done a bootstrap on a little endian Power8 system and it had no
regressions. The x86-64 bootstrap just entered stage3. Assuming there are no
regressions on x86-64, can I check this patch into the trunk?
2017-10-30 Michael Meissner <[email protected]>
* builtins.def (DEF_FLOATN_BUILTIN): Change most _Float<N> and
_Float<N>X built-in functions so that the variant without the
"__builtin_" prefix is only enabled for the GNU C language when it
is non-strict ANSI/ISO mode.
(DEF_EXT_LIB_FLOATN_NX_BUILTINS): Likewise.
* target.def (floatn_builtin_p): Add a target hook to control
whether _Float<N> and _Float<N>X built-in functions without the
"__builtin_" prefix are enabled. Include langhooks.h in
targhooks.c.
* targhooks.h (default_floatn_builtin_p): Likewise.
* targhooks.c (default_floatn_builtin_p): Likewise.
* doc/tm.texi.in (TARGET_FLOATN_BUILTIN_P): Document the
floatn_builtin_p target hook.
* doc/tm.texi (TARGET_FLOATN_BUILTIN_P): Likewise.
--
Michael Meissner, IBM
IBM, M/S 2506R, 550 King Street, Littleton, MA 01460-6245, USA
email: [email protected], phone: +1 (978) 899-4797
Index: gcc/builtins.def
===================================================================
--- gcc/builtins.def (revision 254232)
+++ gcc/builtins.def (working copy)
@@ -130,18 +130,26 @@ along with GCC; see the file COPYING3.
/* A set of GCC builtins for _FloatN and _FloatNx types. TYPE_MACRO is called
with an argument such as FLOAT32 to produce the enum value for the type. If
- we are being fully conformant we ignore the version of these builtins that
- does not being with __builtin_. */
+ we are compiling for the C language with GNU extensions, we enable the name
+ without the __builtin_ prefix as well as the name with the __builtin_
+ prefix. C++ does not enable these names by default because they don't have
+ the _Float<N> and _Float<N>X keywords, and a class based library should use
+ the __builtin_ names. */
+#undef DEF_FLOATN_BUILTIN
+#define DEF_FLOATN_BUILTIN(ENUM, NAME, TYPE, ATTRS) \
+ DEF_BUILTIN (ENUM, "__builtin_" NAME, BUILT_IN_NORMAL, TYPE, TYPE, \
+ targetm.floatn_builtin_p ((int) ENUM), \
+ targetm.floatn_builtin_p ((int) ENUM), true, ATTRS, false, true)
#undef DEF_EXT_LIB_FLOATN_NX_BUILTINS
-#define DEF_EXT_LIB_FLOATN_NX_BUILTINS(ENUM, NAME, TYPE_MACRO, ATTRS)
\
- DEF_EXT_LIB_BUILTIN (ENUM ## F16, NAME "f16", TYPE_MACRO (FLOAT16), ATTRS) \
- DEF_EXT_LIB_BUILTIN (ENUM ## F32, NAME "f32", TYPE_MACRO (FLOAT32), ATTRS) \
- DEF_EXT_LIB_BUILTIN (ENUM ## F64, NAME "f64", TYPE_MACRO (FLOAT64), ATTRS) \
- DEF_EXT_LIB_BUILTIN (ENUM ## F128, NAME "f128", TYPE_MACRO (FLOAT128),
ATTRS)\
- DEF_EXT_LIB_BUILTIN (ENUM ## F32X, NAME "f32x", TYPE_MACRO (FLOAT32X),
ATTRS)\
- DEF_EXT_LIB_BUILTIN (ENUM ## F64X, NAME "f64x", TYPE_MACRO (FLOAT64X),
ATTRS)\
- DEF_EXT_LIB_BUILTIN (ENUM ## F128X, NAME "f128x", TYPE_MACRO (FLOAT128X), \
- ATTRS)
+#define DEF_EXT_LIB_FLOATN_NX_BUILTINS(ENUM, NAME, TYPE_MACRO, ATTRS) \
+ DEF_FLOATN_BUILTIN (ENUM ## F16, NAME "f16", TYPE_MACRO (FLOAT16), ATTRS) \
+ DEF_FLOATN_BUILTIN (ENUM ## F32, NAME "f32", TYPE_MACRO (FLOAT32), ATTRS) \
+ DEF_FLOATN_BUILTIN (ENUM ## F64, NAME "f64", TYPE_MACRO (FLOAT64), ATTRS) \
+ DEF_FLOATN_BUILTIN (ENUM ## F128, NAME "f128", TYPE_MACRO (FLOAT128), ATTRS)
\
+ DEF_FLOATN_BUILTIN (ENUM ## F32X, NAME "f32x", TYPE_MACRO (FLOAT32X), ATTRS)
\
+ DEF_FLOATN_BUILTIN (ENUM ## F64X, NAME "f64x", TYPE_MACRO (FLOAT64X), ATTRS)
\
+ DEF_FLOATN_BUILTIN (ENUM ## F128X, NAME "f128x", TYPE_MACRO (FLOAT128X), \
+ ATTRS)
/* Like DEF_LIB_BUILTIN, except that the function is only a part of
the standard in C94 or above. */
Index: gcc/target.def
===================================================================
--- gcc/target.def (revision 254232)
+++ gcc/target.def (working copy)
@@ -3458,6 +3458,19 @@ if @var{extended} is false, 16 or greate
opt_scalar_float_mode, (int n, bool extended),
default_floatn_mode)
+DEFHOOK
+(floatn_builtin_p,
+ "Define this to return true if the @code{_Float@var{n}} and\n\
+@code{_Float@var{n}x} built-in functions should implicitly enable the\n\
+built-in function without the @code{__builtin_} prefix in addition to the\n\
+normal built-in function with the @code{__builtin_} prefix. The default is\n\
+to only enable built-in functions without the @code{__builtin_} prefix for\n\
+the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
+the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is
the\n\
+@code{enum builtin_in_function} id of the function to be enabled.",
+ bool, (int func),
+ default_floatn_builtin_p)
+
/* Compute cost of moving data from a register of class FROM to one of
TO, using MODE. */
DEFHOOK
Index: gcc/targhooks.h
===================================================================
--- gcc/targhooks.h (revision 254232)
+++ gcc/targhooks.h (working copy)
@@ -75,6 +75,7 @@ extern tree default_mangle_assembler_nam
extern bool default_scalar_mode_supported_p (scalar_mode);
extern bool default_libgcc_floating_mode_supported_p (scalar_float_mode);
extern opt_scalar_float_mode default_floatn_mode (int, bool);
+extern bool default_floatn_builtin_p (int);
extern bool targhook_words_big_endian (void);
extern bool targhook_float_words_big_endian (void);
extern bool default_float_exceptions_rounding_supported_p (void);
Index: gcc/targhooks.c
===================================================================
--- gcc/targhooks.c (revision 254232)
+++ gcc/targhooks.c (working copy)
@@ -81,7 +81,7 @@ along with GCC; see the file COPYING3.
#include "predict.h"
#include "params.h"
#include "real.h"
-
+#include "langhooks.h"
bool
default_legitimate_address_p (machine_mode mode ATTRIBUTE_UNUSED,
@@ -563,6 +563,19 @@ default_floatn_mode (int n, bool extende
return opt_scalar_float_mode ();
}
+/* Define this to return true if the _Floatn and _Floatnx built-in functions
+ should implicitly enable the built-in function without the __builtin_ prefix
+ in addition to the normal built-in function with the __builtin_ prefix. The
+ default is to only enable built-in functions without the __builtin_ prefix
+ for the GNU C langauge. The argument FUNC is the enum builtin_in_function
+ id of the function to be enabled. */
+
+bool
+default_floatn_builtin_p (int func ATTRIBUTE_UNUSED)
+{
+ return lang_GNU_C ();
+}
+
/* Make some target macros useable by target-independent code. */
bool
targhook_words_big_endian (void)
Index: gcc/doc/tm.texi.in
===================================================================
--- gcc/doc/tm.texi.in (revision 254232)
+++ gcc/doc/tm.texi.in (working copy)
@@ -3326,6 +3326,8 @@ stack.
@hook TARGET_FLOATN_MODE
+@hook TARGET_FLOATN_BUILTIN_P
+
@hook TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P
@node Scalar Return
Index: gcc/doc/tm.texi
===================================================================
--- gcc/doc/tm.texi (revision 254232)
+++ gcc/doc/tm.texi (working copy)
@@ -4284,6 +4284,17 @@ ISO/IEC TS 18661-3:2015; that is, @var{n
if @var{extended} is false, 16 or greater than 128 and a multiple of 32.
@end deftypefn
+@deftypefn {Target Hook} bool TARGET_FLOATN_BUILTIN_P (int @var{func})
+Define this to return true if the @code{_Float@var{n}} and
+@code{_Float@var{n}x} built-in functions should implicitly enable the
+built-in function without the @code{__builtin_} prefix in addition to the
+normal built-in function with the @code{__builtin_} prefix. The default is
+to only enable built-in functions without the @code{__builtin_} prefix for
+the GNU C langauge. In strict ANSI/ISO mode, the built-in function without
+the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the
+@code{enum builtin_in_function} id of the function to be enabled.
+@end deftypefn
+
@deftypefn {Target Hook} bool TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P
(machine_mode @var{mode})
Define this to return nonzero for machine modes for which the port has
small register classes. If this target hook returns nonzero for a given
