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Use type-specific precision when printing results in libm-test.inc.

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When libm-test.inc prints the results of failing tests, the output can
be unhelpful for ldbl-128 and ldbl-128ibm because the precision used
is insufficient to distinguish values of those types, resulting in
reported values that look identical but differ by a large number of
ulps.

This patch changes it to use a precision appropriate for the type, for
both decimal and hex output (so output for float is more compact,
output for ldbl-128 and ldbl-128ibm is substantially wider).  The
natural precision to use for decimal is given by the C11 <float.h>
macros such as FLT_DECIMAL_DIG.  GCC's <float.h> only defines those in
C11 mode, so this patch uses the predefines such as
__FLT_DECIMAL_DIG__ (added in GCC 4.6) instead; if we move to building
with -std=gnu11 (or -std=gnu1x if we can't get rid of 4.6 support).

Tested for powerpc and mips64.

	* math/libm-test.inc (TYPE_DECIMAL_DIG): New macro.
	(TYPE_HEX_DIG): Likewise.
	(print_float): Use TYPE_DECIMAL_DIG - 1 and TYPE_HEX_DIG - 1 as
	precisions when printing floating-point numbers.
	(check_float_internal): Likewise.
This commit is contained in:
Joseph Myers 2015-10-01 15:24:54 +00:00
parent 7cda516f5f
commit e27fcd027c
2 changed files with 24 additions and 3 deletions
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8
ChangeLog
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@ -1,3 +1,11 @@
2015-10-01 Joseph Myers <joseph@codesourcery.com>
* math/libm-test.inc (TYPE_DECIMAL_DIG): New macro.
(TYPE_HEX_DIG): Likewise.
(print_float): Use TYPE_DECIMAL_DIG - 1 and TYPE_HEX_DIG - 1 as
precisions when printing floating-point numbers.
(check_float_internal): Likewise.
2015-09-30 Joseph Myers <joseph@codesourcery.com>
[BZ #16620]

19
math/libm-test.inc
View File

@ -338,6 +338,18 @@ static FLOAT max_valid_error;
(LDBL_MANT_DIG-1), (DBL_MANT_DIG-1), (FLT_MANT_DIG-1))
#define MIN_EXP CHOOSE ((LDBL_MIN_EXP-1), (DBL_MIN_EXP-1), (FLT_MIN_EXP-1), \
(LDBL_MIN_EXP-1), (DBL_MIN_EXP-1), (FLT_MIN_EXP-1))
/* Sufficient numbers of digits to represent any floating-point value
unambiguously (for any choice of the number of bits in the first
hex digit, in the case of TYPE_HEX_DIG). When used with printf
formats where the precision counts only digits after the point, 1
is subtracted from these values. */
#define TYPE_DECIMAL_DIG CHOOSE (__DECIMAL_DIG__, \
__DBL_DECIMAL_DIG__, \
__FLT_DECIMAL_DIG__, \
__DECIMAL_DIG__, \
__DBL_DECIMAL_DIG__, \
__FLT_DECIMAL_DIG__)
#define TYPE_HEX_DIG ((MANT_DIG + 7) / 4)
/* Compare KEY (a string, with the name of a function) with ULP (a
pointer to a struct ulp_data structure), returning a value less
@ -419,7 +431,8 @@ print_float (FLOAT f)
else if (isnan (f))
printf ("qNaN\n");
else
printf ("% .20" PRINTF_EXPR " % .20" PRINTF_XEXPR "\n", f, f);
printf ("% .*" PRINTF_EXPR " % .*" PRINTF_XEXPR "\n",
TYPE_DECIMAL_DIG - 1, f, TYPE_HEX_DIG - 1, f);
}
/* Should the message print to screen? This depends on the verbose flag,
@ -837,8 +850,8 @@ check_float_internal (const char *test_name, FLOAT computed, FLOAT expected,
print_float (expected);
if (print_diff)
{
printf (" difference: % .20" PRINTF_EXPR " % .20" PRINTF_XEXPR
"\n", diff, diff);
printf (" difference: % .*" PRINTF_EXPR " % .*" PRINTF_XEXPR
"\n", TYPE_DECIMAL_DIG - 1, diff, TYPE_HEX_DIG - 1, diff);
printf (" ulp : % .4" PRINTF_NEXPR "\n", ulps);
printf (" max.ulp : % .4" PRINTF_NEXPR "\n", max_ulp);
}