[PATCH, version 5a], Add support for _Float<N> and _Float<N>X sqrt, fma, fmin, fmax built-in functions

[Michael Meissner]

On Mon, Oct 30, 2017 at 11:30:12PM +0000, Joseph Myers wrote:
> On Mon, 30 Oct 2017, Michael Meissner wrote:
> 
> > 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).
> 
> Testing lang_GNU_C () can't possibly be correct here; ObjC should always 
> be handled like C unless there is a strong reason not to do so, explicitly 
> commented.
> 
> Also, I'd expect the FALLBACK_P argument to DEF_BUILTIN to be true, not a 
> call to the hook; __builtin_sqrtf128 should always end up generating a 
> call to the out-of-line sqrtf128 function if not inlined, regardless of 
> source language.

This patch fixes both issues.  I have done bootstrap builds on both a little
endian power8 and an x86-64 system with no regressions.  Can I check this into
the trunk?

Assuming the following patch is ok, I have another patch that is awaiting
review:
https://gcc.gnu.org/ml/gcc-patches/2017-10/msg02124.html

2017-10-31  Michael Meissner  <meissner@linux.vnet.ibm.com>

	* 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 and Objective C
	languages when they are in 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, and return true for C and
	Objective C in the default hook.  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: meissner@linux.vnet.ibm.com, phone: +1 (978) 899-4797
-------------- next part --------------
Index: gcc/builtins.def
===================================================================
--- gcc/builtins.def	(revision 254243)
+++ 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), true, 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 254243)
+++ 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 254243)
+++ 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 254243)
+++ 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 +563,28 @@ 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)
+{
+  static bool first_time_p = true;
+  static bool c_or_objective_c;
+
+  if (first_time_p)
+    {
+      first_time_p = false;
+      c_or_objective_c = lang_GNU_C () || lang_GNU_OBJC ();
+    }
+
+  return c_or_objective_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 254243)
+++ 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 254243)
+++ 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