From a820f9b3c0cb5e80cd892b0f9c1c48f48bd4413f Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Mon, 16 Feb 2015 22:38:28 +0000 Subject: Fix remquo spurious overflows (bug 17978). Various remquo implementations, when computing the last three bits of the quotient, have spurious overflows when 4 times the second argument to remquo overflows. These overflows can in turn cause bad results in rounding modes where that overflow results in a finite value. This patch adds tests to avoid the problem multiplications in cases where they would overflow, similar to those that control an earlier multiplication by 8. Tested for x86_64, x86, mips64 and powerpc. [BZ #17978] * sysdeps/ieee754/dbl-64/s_remquo.c (__remquo): Do not form products 4 * y and 2 * y where those would overflow. * sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c (__remquo): Likewise. * sysdeps/ieee754/flt-32/s_remquof.c (__remquof): Likewise. * sysdeps/ieee754/ldbl-128/s_remquol.c (__remquol): Likewise. * sysdeps/ieee754/ldbl-128ibm/s_remquol.c (__remquol): Likewise. * sysdeps/ieee754/ldbl-96/s_remquol.c (__remquol): Likewise. * math/libm-test.inc (remquo_test_data): Add more tests. --- ChangeLog | 11 ++++++ NEWS | 2 +- math/libm-test.inc | 54 +++++++++++++++++++++++++++ sysdeps/ieee754/dbl-64/s_remquo.c | 4 +- sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c | 4 +- sysdeps/ieee754/flt-32/s_remquof.c | 4 +- sysdeps/ieee754/ldbl-128/s_remquol.c | 4 +- sysdeps/ieee754/ldbl-128ibm/s_remquol.c | 4 +- sysdeps/ieee754/ldbl-96/s_remquol.c | 4 +- 9 files changed, 78 insertions(+), 13 deletions(-) diff --git a/ChangeLog b/ChangeLog index c09d9f8148..cde2c5ae1d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,16 @@ 2015-02-16 Joseph Myers + [BZ #17978] + * sysdeps/ieee754/dbl-64/s_remquo.c (__remquo): Do not form + products 4 * y and 2 * y where those would overflow. + * sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c (__remquo): + Likewise. + * sysdeps/ieee754/flt-32/s_remquof.c (__remquof): Likewise. + * sysdeps/ieee754/ldbl-128/s_remquol.c (__remquol): Likewise. + * sysdeps/ieee754/ldbl-128ibm/s_remquol.c (__remquol): Likewise. + * sysdeps/ieee754/ldbl-96/s_remquol.c (__remquol): Likewise. + * math/libm-test.inc (remquo_test_data): Add more tests. + * sysdeps/mips/sgidefs.h [!_ABIO64] (_ABIO64): New macro. * sysdeps/mips/memcpy.S [_COMPILING_NEWLIB]: Change condition to diff --git a/NEWS b/NEWS index 781f7a7bf1..4f4f740af0 100644 --- a/NEWS +++ b/NEWS @@ -10,7 +10,7 @@ Version 2.22 * The following bugs are resolved with this release: 4719, 15467, 15790, 16560, 17569, 17792, 17912, 17932, 17944, 17949, - 17964, 17965, 17967, 17969. + 17964, 17965, 17967, 17969, 17978. Version 2.21 diff --git a/math/libm-test.inc b/math/libm-test.inc index 2f3902a445..1cf80e3379 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -8764,6 +8764,60 @@ static const struct test_ffI_f1_data remquo_test_data[] = TEST_ffI_f1 (remquo, -3419, 360, -179, -1, NO_INEXACT_EXCEPTION), TEST_ffI_f1 (remquo, 3419, -360, 179, -1, NO_INEXACT_EXCEPTION), TEST_ffI_f1 (remquo, -3419, -360, -179, 1, NO_INEXACT_EXCEPTION), + + TEST_ffI_f1 (remquo, max_value, max_value, plus_zero, 1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, max_value, -max_value, plus_zero, -1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, max_value, min_value, plus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, max_value, -min_value, plus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, max_value, min_subnorm_value, plus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, max_value, -min_subnorm_value, plus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -max_value, max_value, minus_zero, -1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -max_value, -max_value, minus_zero, 1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -max_value, min_value, minus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -max_value, -min_value, minus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -max_value, min_subnorm_value, minus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -max_value, -min_subnorm_value, minus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_value, max_value, min_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_value, -max_value, min_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_value, min_value, plus_zero, 1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_value, -min_value, plus_zero, -1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_value, min_subnorm_value, plus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_value, -min_subnorm_value, plus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_value, max_value, -min_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_value, -max_value, -min_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_value, min_value, minus_zero, -1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_value, -min_value, minus_zero, 1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_value, min_subnorm_value, minus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_value, -min_subnorm_value, minus_zero, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_subnorm_value, max_value, min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_subnorm_value, -max_value, min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_subnorm_value, min_value, min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_subnorm_value, -min_value, min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_subnorm_value, min_subnorm_value, plus_zero, 1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, min_subnorm_value, -min_subnorm_value, plus_zero, -1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_subnorm_value, max_value, -min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_subnorm_value, -max_value, -min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_subnorm_value, min_value, -min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_subnorm_value, -min_value, -min_subnorm_value, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_subnorm_value, min_subnorm_value, minus_zero, -1, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -min_subnorm_value, -min_subnorm_value, minus_zero, 1, NO_INEXACT_EXCEPTION), + + TEST_ffI_f1 (remquo, 1, max_value, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, -max_value, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, max_value / 2, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, -max_value / 2, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, max_value / 4, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, -max_value / 4, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, max_value / 8, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, 1, -max_value / 8, 1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, max_value, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, -max_value, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, max_value / 2, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, -max_value / 2, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, max_value / 4, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, -max_value / 4, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, max_value / 8, -1, 0, NO_INEXACT_EXCEPTION), + TEST_ffI_f1 (remquo, -1, -max_value / 8, -1, 0, NO_INEXACT_EXCEPTION), }; static void diff --git a/sysdeps/ieee754/dbl-64/s_remquo.c b/sysdeps/ieee754/dbl-64/s_remquo.c index 2724902908..e07efa89f8 100644 --- a/sysdeps/ieee754/dbl-64/s_remquo.c +++ b/sysdeps/ieee754/dbl-64/s_remquo.c @@ -60,12 +60,12 @@ __remquo (double x, double y, int *quo) y = fabs (y); cquo = 0; - if (x >= 4 * y) + if (hy <= 0x7fcfffff && x >= 4 * y) { x -= 4 * y; cquo += 4; } - if (x >= 2 * y) + if (hy <= 0x7fdfffff && x >= 2 * y) { x -= 2 * y; cquo += 2; diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c index 5b7142576a..ab561780c8 100644 --- a/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c @@ -59,12 +59,12 @@ __remquo (double x, double y, int *quo) INSERT_WORDS64 (y, hy); cquo = 0; - if (x >= 4 * y) + if (hy <= UINT64_C(0x7fcfffffffffffff) && x >= 4 * y) { x -= 4 * y; cquo += 4; } - if (x >= 2 * y) + if (hy <= UINT64_C(0x7fdfffffffffffff) && x >= 2 * y) { x -= 2 * y; cquo += 2; diff --git a/sysdeps/ieee754/flt-32/s_remquof.c b/sysdeps/ieee754/flt-32/s_remquof.c index a9cdf8fb98..04944fdcd3 100644 --- a/sysdeps/ieee754/flt-32/s_remquof.c +++ b/sysdeps/ieee754/flt-32/s_remquof.c @@ -59,12 +59,12 @@ __remquof (float x, float y, int *quo) y = fabsf (y); cquo = 0; - if (x >= 4 * y) + if (hy <= 0x7e7fffff && x >= 4 * y) { x -= 4 * y; cquo += 4; } - if (x >= 2 * y) + if (hy <= 0x7effffff && x >= 2 * y) { x -= 2 * y; cquo += 2; diff --git a/sysdeps/ieee754/ldbl-128/s_remquol.c b/sysdeps/ieee754/ldbl-128/s_remquol.c index 8543265f1a..da175a14f6 100644 --- a/sysdeps/ieee754/ldbl-128/s_remquol.c +++ b/sysdeps/ieee754/ldbl-128/s_remquol.c @@ -61,12 +61,12 @@ __remquol (long double x, long double y, int *quo) y = fabsl (y); cquo = 0; - if (x >= 4 * y) + if (hy <= 0x7ffcffffffffffffLL && x >= 4 * y) { x -= 4 * y; cquo += 4; } - if (x >= 2 * y) + if (hy <= 0x7ffdffffffffffffLL && x >= 2 * y) { x -= 2 * y; cquo += 2; diff --git a/sysdeps/ieee754/ldbl-128ibm/s_remquol.c b/sysdeps/ieee754/ldbl-128ibm/s_remquol.c index e36af52d77..ac228796b0 100644 --- a/sysdeps/ieee754/ldbl-128ibm/s_remquol.c +++ b/sysdeps/ieee754/ldbl-128ibm/s_remquol.c @@ -66,12 +66,12 @@ __remquol (long double x, long double y, int *quo) y = fabsl (y); cquo = 0; - if (x >= 4 * y) + if (hy <= 0x7fcfffffffffffffLL && x >= 4 * y) { x -= 4 * y; cquo += 4; } - if (x >= 2 * y) + if (hy <= 0x7fdfffffffffffffLL && x >= 2 * y) { x -= 2 * y; cquo += 2; diff --git a/sysdeps/ieee754/ldbl-96/s_remquol.c b/sysdeps/ieee754/ldbl-96/s_remquol.c index 6b3499d257..1462b54456 100644 --- a/sysdeps/ieee754/ldbl-96/s_remquol.c +++ b/sysdeps/ieee754/ldbl-96/s_remquol.c @@ -60,12 +60,12 @@ __remquol (long double x, long double p, int *quo) p = fabsl (p); cquo = 0; - if (x >= 4 * p) + if (ep <= 0x7ffc && x >= 4 * p) { x -= 4 * p; cquo += 4; } - if (x >= 2 * p) + if (ep <= 0x7ffd && x >= 2 * p) { x -= 2 * p; cquo += 2; -- cgit 1.4.1