From 876c5bd30cf44ab47ee46c08d06e6ba9ab2b338f Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Tue, 24 May 2016 17:44:46 +0000 Subject: [PATCH] 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. --- ChangeLog | 18 ++++++++++ sysdeps/ieee754/dbl-64/s_floor.c | 10 ++---- sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c | 9 ++--- sysdeps/ieee754/flt-32/s_floorf.c | 9 ++--- sysdeps/ieee754/ldbl-128/s_floorl.c | 37 ++++++++------------ 5 files changed, 38 insertions(+), 45 deletions(-) diff --git a/ChangeLog b/ChangeLog index b074f4d980..7837544563 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,23 @@ 2016-05-24 Joseph Myers + [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. diff --git a/sysdeps/ieee754/dbl-64/s_floor.c b/sysdeps/ieee754/dbl-64/s_floor.c index bd6afa72e8..8f86aa31ee 100644 --- a/sysdeps/ieee754/dbl-64/s_floor.c +++ b/sysdeps/ieee754/dbl-64/s_floor.c @@ -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 #include -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) diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c index b7ed14bfa2..8d514f23bc 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_floor.c @@ -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); } diff --git a/sysdeps/ieee754/flt-32/s_floorf.c b/sysdeps/ieee754/flt-32/s_floorf.c index 99d6c01833..69160e5e10 100644 --- a/sysdeps/ieee754/flt-32/s_floorf.c +++ b/sysdeps/ieee754/flt-32/s_floorf.c @@ -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 #include -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); } diff --git a/sysdeps/ieee754/ldbl-128/s_floorl.c b/sysdeps/ieee754/ldbl-128/s_floorl.c index c72d5d4330..14a0efef85 100644 --- a/sysdeps/ieee754/ldbl-128/s_floorl.c +++ b/sysdeps/ieee754/ldbl-128/s_floorl.c @@ -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 #include -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