diff options
| author | Joseph Myers <joseph@codesourcery.com> | 2016-05-24 17:46:55 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2016-05-24 17:46:55 +0000 |
| commit | 078d1cf8accf8e74390c3b091549afa4efbb113e (patch) | |
| tree | 1a098004bed55cfe49d11ac8f79642cd44a436aa /sysdeps/ieee754/dbl-64 | |
| parent | 876c5bd30cf44ab47ee46c08d06e6ba9ab2b338f (diff) | |
| download | glibc-078d1cf8accf8e74390c3b091549afa4efbb113e.tar.gz glibc-078d1cf8accf8e74390c3b091549afa4efbb113e.tar.xz glibc-078d1cf8accf8e74390c3b091549afa4efbb113e.zip | |
Do not raise "inexact" from generic round (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 round functions to align them with TS 18661-1 in this regard. The tests *are* updated by this patch; there are fewer architecture-specific versions than for ceil and floor, and I fixed the powerpc ones some time ago. If any others still have the issue, as shown by tests for round failing with spurious exceptions, they can be fixed separately by architecture maintainers or others. Tested for x86_64, x86 and mips64. [BZ #15479] * sysdeps/ieee754/dbl-64/s_round.c (huge): Remove variable. (__round): Do not force "inexact" exception. * sysdeps/ieee754/dbl-64/wordsize-64/s_round.c (huge): Remove variable. (__round): Do not force "inexact" exception. * sysdeps/ieee754/flt-32/s_roundf.c (huge): Remove variable. (__roundf): Do not force "inexact" exception. * sysdeps/ieee754/ldbl-128/s_roundl.c (huge): Remove variable. (__roundl): Do not force "inexact" exception. * sysdeps/ieee754/ldbl-96/s_roundl.c (huge): Remove variable. (__roundl): Do not force "inexact" exception. * math/libm-test.inc (round_test_data): Do not allow spurious "inexact" exceptions.
Diffstat (limited to 'sysdeps/ieee754/dbl-64')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/s_round.c | 10 | ||||
| -rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_round.c | 6 |
2 files changed, 0 insertions, 16 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_round.c b/sysdeps/ieee754/dbl-64/s_round.c index aeed6faf0e..4fe305b3ff 100644 --- a/sysdeps/ieee754/dbl-64/s_round.c +++ b/sysdeps/ieee754/dbl-64/s_round.c @@ -22,9 +22,6 @@ #include <math_private.h> -static const double huge = 1.0e300; - - double __round (double x) { @@ -37,8 +34,6 @@ __round (double x) { if (j0 < 0) { - math_force_eval (huge + x); - i0 &= 0x80000000; if (j0 == -1) i0 |= 0x3ff00000; @@ -50,9 +45,7 @@ __round (double x) if (((i0 & i) | i1) == 0) /* X is integral. */ return x; - math_force_eval (huge + x); - /* Raise inexact if x != 0. */ i0 += 0x00080000 >> j0; i0 &= ~i; i1 = 0; @@ -73,9 +66,6 @@ __round (double x) /* X is integral. */ return x; - math_force_eval (huge + x); - - /* Raise inexact if x != 0. */ u_int32_t j = i1 + (1 << (51 - j0)); if (j < i1) i0 += 1; diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c index f1d75bbe68..688e6af016 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_round.c @@ -22,8 +22,6 @@ #include <math_private.h> #include <stdint.h> -static const double huge = 1.0e300; - double __round (double x) @@ -36,8 +34,6 @@ __round (double x) { if (j0 < 0) { - math_force_eval (huge + x); - i0 &= UINT64_C(0x8000000000000000); if (j0 == -1) i0 |= UINT64_C(0x3ff0000000000000); @@ -48,9 +44,7 @@ __round (double x) if ((i0 & i) == 0) /* X is integral. */ return x; - math_force_eval (huge + x); - /* Raise inexact if x != 0. */ i0 += UINT64_C(0x0008000000000000) >> j0; i0 &= ~i; } |