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Add C2x *_NORM_MAX constants to <float.h>. 

C2x adds <float.h> constants FLT_NORM_MAX, DBL_NORM_MAX and
LDBL_NORM_MAX.  These are for the maximum "normalized" finite
floating-point number, where the given definition of normalized is
that all possible values with MANT_DIG significand digits (leading one
not zero) can be represented with that exponent.  The effect of that
definition is that these macros are the same as the corresponding MAX
macros for all formats except IBM long double, where the NORM_MAX
value has exponent 1 smaller than the MAX one so that all 106 digits
can be 1.

This patch adds those macros to GCC.  They are only defined for float,
double and long double; C2x does not include such macros for DFP
types, and while the integration of TS 18661-3 into C2x has not yet
occurred, the draft proposed text does not add them for the _FloatN /
_FloatNx types (where they would always be the same as the MAX
macros).

Bootstrapped with no regressions on x86_64-pc-linux-gnu.  Also tested
compilation of the new test for powerpc-linux-gnu to confirm the check
of LDBL_NORM_MAX in the IBM long double case does get properly
optimized out.

gcc:
	* ginclude/float.c [__STDC_VERSION__ > 201710L] (FLT_NORM_MAX,
	DBL_NORM_MAX, LDBL_NORM_MAX): Define.
	* real.c (get_max_float): Add norm_max argument.
	* real.h (get_max_float): Update prototype.
	* builtins.c (fold_builtin_interclass_mathfn): Update calls to
	get_max_float.

gcc/c-family:
	* c-cppbuiltin.c (builtin_define_float_constants): Also define
	NORM_MAX constants.  Update call to get_max_float.
	(LAZY_HEX_FP_VALUES_CNT): Update value to include NORM_MAX
	constants.

gcc/d:
	* d-target.cc (define_float_constants): Update call to
	get_max_float.

gcc/testsuite:
	* gcc.dg/c11-float-3.c, gcc.dg/c2x-float-1.c: New tests.

From-SVN: r278145
This commit is contained in:
Joseph Myers 2019-11-13 15:25:15 +00:00 committed by Joseph Myers
parent 5024c8bb46
commit 00be2a5f39
12 changed files with 115 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
gcc/ChangeLog
View File

@ -1,3 +1,12 @@
2019-11-13 Joseph Myers <joseph@codesourcery.com>
* ginclude/float.c [__STDC_VERSION__ > 201710L] (FLT_NORM_MAX,
DBL_NORM_MAX, LDBL_NORM_MAX): Define.
* real.c (get_max_float): Add norm_max argument.
* real.h (get_max_float): Update prototype.
* builtins.c (fold_builtin_interclass_mathfn): Update calls to
get_max_float.
2019-11-13 Martin Liska <mliska@suse.cz>
* dbgcnt.c (test_sorted_dbg_counters): New.

6
gcc/builtins.c
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@ -9038,7 +9038,7 @@ fold_builtin_interclass_mathfn (location_t loc, tree fndecl, tree arg)
mode = DFmode;
arg = fold_build1_loc (loc, NOP_EXPR, type, arg);
}
get_max_float (REAL_MODE_FORMAT (mode), buf, sizeof (buf));
get_max_float (REAL_MODE_FORMAT (mode), buf, sizeof (buf), false);
real_from_string (&r, buf);
result = build_call_expr (isgr_fn, 2,
fold_build1_loc (loc, ABS_EXPR, type, arg),
@ -9062,7 +9062,7 @@ fold_builtin_interclass_mathfn (location_t loc, tree fndecl, tree arg)
mode = DFmode;
arg = fold_build1_loc (loc, NOP_EXPR, type, arg);
}
get_max_float (REAL_MODE_FORMAT (mode), buf, sizeof (buf));
get_max_float (REAL_MODE_FORMAT (mode), buf, sizeof (buf), false);
real_from_string (&r, buf);
result = build_call_expr (isle_fn, 2,
fold_build1_loc (loc, ABS_EXPR, type, arg),
@ -9101,7 +9101,7 @@ fold_builtin_interclass_mathfn (location_t loc, tree fndecl, tree arg)
}
arg = fold_build1_loc (loc, ABS_EXPR, type, arg);
get_max_float (REAL_MODE_FORMAT (mode), buf, sizeof (buf));
get_max_float (REAL_MODE_FORMAT (mode), buf, sizeof (buf), false);
real_from_string (&rmax, buf);
sprintf (buf, "0x1p%d", REAL_MODE_FORMAT (orig_mode)->emin - 1);
real_from_string (&rmin, buf);

7
gcc/c-family/ChangeLog
View File

@ -1,3 +1,10 @@
2019-11-13 Joseph Myers <joseph@codesourcery.com>
* c-cppbuiltin.c (builtin_define_float_constants): Also define
NORM_MAX constants. Update call to get_max_float.
(LAZY_HEX_FP_VALUES_CNT): Update value to include NORM_MAX
constants.
2019-11-13 Eric Botcazou <ebotcazou@adacore.com>
* c-ada-spec.c (get_underlying_decl): Do not look through typedefs.

11
gcc/c-family/c-cppbuiltin.c
View File

@ -259,11 +259,16 @@ builtin_define_float_constants (const char *name_prefix,
/* Since, for the supported formats, B is always a power of 2, we
construct the following numbers directly as a hexadecimal
constants. */
get_max_float (fmt, buf, sizeof (buf));
get_max_float (fmt, buf, sizeof (buf), false);
sprintf (name, "__%s_MAX__", name_prefix);
builtin_define_with_hex_fp_value (name, type, decimal_dig, buf, fp_suffix, fp_cast);
get_max_float (fmt, buf, sizeof (buf), true);
sprintf (name, "__%s_NORM_MAX__", name_prefix);
builtin_define_with_hex_fp_value (name, type, decimal_dig, buf, fp_suffix, fp_cast);
/* The minimum normalized positive floating-point number,
b**(emin-1). */
sprintf (name, "__%s_MIN__", name_prefix);
@ -1607,10 +1612,10 @@ struct GTY(()) lazy_hex_fp_value_struct
};
/* Number of the expensive to compute macros we should evaluate lazily.
Each builtin_define_float_constants invocation calls
builtin_define_with_hex_fp_value 4 times and builtin_define_float_constants
builtin_define_with_hex_fp_value 5 times and builtin_define_float_constants
is called for FLT, DBL, LDBL and up to NUM_FLOATN_NX_TYPES times for
FLTNN*. */
#define LAZY_HEX_FP_VALUES_CNT (4 * (3 + NUM_FLOATN_NX_TYPES))
#define LAZY_HEX_FP_VALUES_CNT (5 * (3 + NUM_FLOATN_NX_TYPES))
static GTY(()) struct lazy_hex_fp_value_struct
lazy_hex_fp_values[LAZY_HEX_FP_VALUES_CNT];
static GTY(()) unsigned lazy_hex_fp_value_count;

5
gcc/d/ChangeLog
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@ -1,3 +1,8 @@
2019-11-13 Joseph Myers <joseph@codesourcery.com>
* d-target.cc (define_float_constants): Update call to
get_max_float.
2019-11-04 Richard Sandiford <richard.sandiford@arm.com>
* d-builtins.cc (build_frontend_type): Cope with variable

2
gcc/d/d-target.cc
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@ -82,7 +82,7 @@ define_float_constants (tree type)
const real_format *fmt = REAL_MODE_FORMAT (mode);
/* The largest representable value that's not infinity. */
get_max_float (fmt, buf, sizeof (buf));
get_max_float (fmt, buf, sizeof (buf), false);
real_from_string (&T::max.rv (), buf);
/* The smallest representable normalized value that's not 0. */

12
gcc/ginclude/float.h
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@ -238,6 +238,18 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#endif /* C11 */
#if defined __STDC_VERSION__ && __STDC_VERSION__ > 201710L
/* Maximum finite positive value with MANT_DIG digits in the
significand taking their maximum value. */
#undef FLT_NORM_MAX
#undef DBL_NORM_MAX
#undef LDBL_NORM_MAX
#define FLT_NORM_MAX __FLT_NORM_MAX__
#define DBL_NORM_MAX __DBL_NORM_MAX__
#define LDBL_NORM_MAX __LDBL_NORM_MAX__
#endif /* C2X */
#ifdef __STDC_WANT_IEC_60559_BFP_EXT__
/* Number of decimal digits for which conversions between decimal
character strings and binary formats, in both directions, are

15
gcc/real.c
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@ -5242,13 +5242,19 @@ real_nextafter (REAL_VALUE_TYPE *r, format_helper fmt,
/* Write into BUF the maximum representable finite floating-point
number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
float string. LEN is the size of BUF, and the buffer must be large
enough to contain the resulting string. */
enough to contain the resulting string. If NORM_MAX, instead write
the maximum representable finite normalized floating-point number,
defined to be such that all choices of digits for that exponent are
representable in the format (this only makes a difference for IBM
long double). */
void
get_max_float (const struct real_format *fmt, char *buf, size_t len)
get_max_float (const struct real_format *fmt, char *buf, size_t len,
bool norm_max)
{
int i, n;
char *p;
bool is_ibm_extended = fmt->pnan < fmt->p;
strcpy (buf, "0x0.");
n = fmt->p;
@ -5256,8 +5262,9 @@ get_max_float (const struct real_format *fmt, char *buf, size_t len)
*p++ = 'f';
if (i < n)
*p++ = "08ce"[n - i];
sprintf (p, "p%d", fmt->emax);
if (fmt->pnan < fmt->p)
sprintf (p, "p%d",
(is_ibm_extended && norm_max) ? fmt->emax - 1 : fmt->emax);
if (is_ibm_extended && !norm_max)
{
/* This is an IBM extended double format made up of two IEEE
doubles. The value of the long double is the sum of the

2
gcc/real.h
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@ -524,7 +524,7 @@ extern bool real_nextafter (REAL_VALUE_TYPE *, format_helper,
/* Write into BUF the maximum representable finite floating-point
number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
float string. BUF must be large enough to contain the result. */
extern void get_max_float (const struct real_format *, char *, size_t);
extern void get_max_float (const struct real_format *, char *, size_t, bool);
#ifndef GENERATOR_FILE
/* real related routines. */

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
2019-11-13 Joseph Myers <joseph@codesourcery.com>
* gcc.dg/c11-float-3.c, gcc.dg/c2x-float-1.c: New tests.
2019-11-13 Martin Jambor <mjambor@suse.cz>
PR ipa/92454

17
gcc/testsuite/gcc.dg/c11-float-3.c Normal file
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@ -0,0 +1,17 @@
/* Test *_NORM_MAX not defined for C11. */
/* { dg-do preprocess } */
/* { dg-options "-std=c11 -pedantic-errors" } */
#include <float.h>
#ifdef FLT_NORM_MAX
#error "FLT_NORM_MAX defined"
#endif
#ifdef DBL_NORM_MAX
#error "DBL_NORM_MAX defined"
#endif
#ifdef LDBL_NORM_MAX
#error "LDBL_NORM_MAX defined"
#endif

37
gcc/testsuite/gcc.dg/c2x-float-1.c Normal file
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@ -0,0 +1,37 @@
/* Test *_NORM_MAX macros. */
/* { dg-do run } */
/* { dg-options "-std=c2x -pedantic-errors" } */
#include <float.h>
#ifndef FLT_NORM_MAX
#error "FLT_NORM_MAX undefined"
#endif
#ifndef DBL_NORM_MAX
#error "DBL_NORM_MAX undefined"
#endif
#ifndef LDBL_NORM_MAX
#error "LDBL_NORM_MAX undefined"
#endif
extern void abort (void);
extern void exit (int);
int
main (void)
{
if (FLT_NORM_MAX != FLT_MAX)
abort ();
if (DBL_NORM_MAX != DBL_MAX)
abort ();
#if LDBL_MANT_DIG == 106
if (LDBL_NORM_MAX != 0x0.ffffffffffffffffffffffffffcp1023L)
abort ();
#else
if (LDBL_NORM_MAX != LDBL_MAX)
abort ();
#endif
exit (0);
}