Do not raise "inexact" from generic floor (bug 15479).

C99 and C11 allow but do not require ceil, floor, round and trunc to
raise the "inexact" exception for noninteger arguments.  TS 18661-1
requires that this exception not be raised by these functions.  This
aligns them with general IEEE semantics, where "inexact" is only
raised if the final step of rounding the infinite-precision result to
the result type is inexact; for these functions, the
infinite-precision integer result is always representable in the
result type, so "inexact" should never be raised.

The generic implementations of ceil, floor and round functions contain
code to force "inexact" to be raised.  This patch removes it for floor
functions to align them with TS 18661-1 in this regard.  Note that
some architecture-specific versions may still raise "inexact", so the
tests are not updated and the bug is not yet fixed.

Tested for x86_64, x86 and mips64.

	[BZ #15479]
	* sysdeps/ieee754/dbl-64/s_floor.c: Do not mention "inexact"
	exception in comment.
	(huge): Remove variable.
	(__floor): Do not force "inexact" exception.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c: Do not mention
	"inexact" exception in comment.
	(huge): Remove variable.
	(__floor): Do not force "inexact" exception.
	* sysdeps/ieee754/flt-32/s_floorf.c: Do not mention "inexact"
	exception in comment.
	(huge): Remove variable.
	(__floorf): Do not force "inexact" exception.
	* sysdeps/ieee754/ldbl-128/s_floorl.c: Do not mention "inexact"
	exception in comment.
	(huge): Remove variable.
	(__floorl): Do not force "inexact" exception.
This commit is contained in:
Joseph Myers 2016-05-24 17:44:46 +00:00
parent ac2cc6f021
commit 876c5bd30c
5 changed files with 38 additions and 45 deletions

View File

@ -1,5 +1,23 @@
2016-05-24 Joseph Myers <joseph@codesourcery.com>
[BZ #15479]
* sysdeps/ieee754/dbl-64/s_floor.c: Do not mention "inexact"
exception in comment.
(huge): Remove variable.
(__floor): Do not force "inexact" exception.
* sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c: Do not mention
"inexact" exception in comment.
(huge): Remove variable.
(__floor): Do not force "inexact" exception.
* sysdeps/ieee754/flt-32/s_floorf.c: Do not mention "inexact"
exception in comment.
(huge): Remove variable.
(__floorf): Do not force "inexact" exception.
* sysdeps/ieee754/ldbl-128/s_floorl.c: Do not mention "inexact"
exception in comment.
(huge): Remove variable.
(__floorl): Do not force "inexact" exception.
[BZ #15479]
* sysdeps/ieee754/dbl-64/s_ceil.c: Do not mention "inexact"
exception in comment.

View File

@ -15,15 +15,11 @@
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to floor(x).
*/
#include <math.h>
#include <math_private.h>
static const double huge = 1.0e300;
double
__floor (double x)
{
@ -33,9 +29,9 @@ __floor (double x)
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
if (j0 < 20)
{
if (j0 < 0) /* raise inexact if x != 0 */
if (j0 < 0)
{
math_force_eval (huge + x); /* return 0*sign(x) if |x|<1 */
/* return 0*sign(x) if |x|<1 */
if (i0 >= 0)
{
i0 = i1 = 0;
@ -50,7 +46,6 @@ __floor (double x)
i = (0x000fffff) >> j0;
if (((i0 & i) | i1) == 0)
return x; /* x is integral */
math_force_eval (huge + x); /* raise inexact flag */
if (i0 < 0)
i0 += (0x00100000) >> j0;
i0 &= (~i); i1 = 0;
@ -68,7 +63,6 @@ __floor (double x)
i = ((u_int32_t) (0xffffffff)) >> (j0 - 20);
if ((i1 & i) == 0)
return x; /* x is integral */
math_force_eval (huge + x); /* raise inexact flag */
if (i0 < 0)
{
if (j0 == 20)

View File

@ -39,12 +39,8 @@
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to floor(x).
*/
static const double huge = 1.0e300;
double
__floor (double x)
@ -53,15 +49,14 @@ __floor (double x)
EXTRACT_WORDS64(i0,x);
int32_t j0 = ((i0>>52)&0x7ff)-0x3ff;
if(__builtin_expect(j0<52, 1)) {
if(j0<0) { /* raise inexact if x != 0 */
math_force_eval(huge+x);/* return 0*sign(x) if |x|<1 */
if(j0<0) {
/* return 0*sign(x) if |x|<1 */
if(i0>=0) {i0=0;}
else if((i0&0x7fffffffffffffffl)!=0)
{ i0=0xbff0000000000000l;}
} else {
uint64_t i = (0x000fffffffffffffl)>>j0;
if((i0&i)==0) return x; /* x is integral */
math_force_eval(huge+x); /* raise inexact flag */
if(i0<0) i0 += (0x0010000000000000l)>>j0;
i0 &= (~i);
}

View File

@ -18,15 +18,11 @@
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to floorf(x).
*/
#include <math.h>
#include <math_private.h>
static const float huge = 1.0e30;
float
__floorf(float x)
{
@ -35,15 +31,14 @@ __floorf(float x)
GET_FLOAT_WORD(i0,x);
j0 = ((i0>>23)&0xff)-0x7f;
if(j0<23) {
if(j0<0) { /* raise inexact if x != 0 */
math_force_eval(huge+x);/* return 0*sign(x) if |x|<1 */
if(j0<0) {
/* return 0*sign(x) if |x|<1 */
if(i0>=0) {i0=0;}
else if((i0&0x7fffffff)!=0)
{ i0=0xbf800000;}
} else {
i = (0x007fffff)>>j0;
if((i0&i)==0) return x; /* x is integral */
math_force_eval(huge+x); /* raise inexact flag */
if(i0<0) i0 += (0x00800000)>>j0;
i0 &= (~i);
}

View File

@ -22,15 +22,11 @@ static char rcsid[] = "$NetBSD: $";
* Return x rounded toward -inf to integral value
* Method:
* Bit twiddling.
* Exception:
* Inexact flag raised if x not equal to floor(x).
*/
#include <math.h>
#include <math_private.h>
static const long double huge = 1.0e4930L;
long double __floorl(long double x)
{
int64_t i0,i1,j0;
@ -38,19 +34,16 @@ long double __floorl(long double x)
GET_LDOUBLE_WORDS64(i0,i1,x);
j0 = ((i0>>48)&0x7fff)-0x3fff;
if(j0<48) {
if(j0<0) { /* raise inexact if x != 0 */
if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
if(i0>=0) {i0=i1=0;}
else if(((i0&0x7fffffffffffffffLL)|i1)!=0)
{ i0=0xbfff000000000000ULL;i1=0;}
}
if(j0<0) {
/* return 0*sign(x) if |x|<1 */
if(i0>=0) {i0=i1=0;}
else if(((i0&0x7fffffffffffffffLL)|i1)!=0)
{ i0=0xbfff000000000000ULL;i1=0;}
} else {
i = (0x0000ffffffffffffULL)>>j0;
if(((i0&i)|i1)==0) return x; /* x is integral */
if(huge+x>0.0) { /* raise inexact flag */
if(i0<0) i0 += (0x0001000000000000LL)>>j0;
i0 &= (~i); i1=0;
}
if(i0<0) i0 += (0x0001000000000000LL)>>j0;
i0 &= (~i); i1=0;
}
} else if (j0>111) {
if(j0==0x4000) return x+x; /* inf or NaN */
@ -58,17 +51,15 @@ long double __floorl(long double x)
} else {
i = -1ULL>>(j0-48);
if((i1&i)==0) return x; /* x is integral */
if(huge+x>0.0) { /* raise inexact flag */
if(i0<0) {
if(j0==48) i0+=1;
else {
j = i1+(1LL<<(112-j0));
if(j<i1) i0 +=1 ; /* got a carry */
i1=j;
}
if(i0<0) {
if(j0==48) i0+=1;
else {
j = i1+(1LL<<(112-j0));
if(j<i1) i0 +=1 ; /* got a carry */
i1=j;
}
i1 &= (~i);
}
i1 &= (~i);
}
SET_LDOUBLE_WORDS64(x,i0,i1);
return x;