From 5a9e4c09a2601a8100ea9a1f7bc0360782cd1625 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Mon, 12 Jan 2015 23:02:14 +0000 Subject: Fix ldbl-96 scalblnl underflowing results (bug 17803). The ldbl-96 implementation of scalblnl (used for x86_64 and ia64) uses a condition k <= -63 to determine when a standard underflowing result tiny*__copysignl(tiny,x) should be returned. However, that condition corresponds to values with exponent -16446 or less, and in the case of -16446, the correct result for round-to-nearest depends on whether the value is exactly 0x1p-16446 (half the least subnormal) or more than that. This patch fixes the bug by changing the condition to k <= -64 and accordingly adjusting the exponent by 64 not 63 when converting to a normal value. Tested for x86_64. [BZ #17803] * sysdeps/ieee754/ldbl-96/s_scalblnl.c (twom63): Rename to twom64. Adjust value to 0x1p-64L. (__scalblnl): Only return standard underflowing result for K <= -64 not K <= -63; adjust exponent for underflowing result by 64 not 63. * math/libm-test.inc (scalbn_test_data): Add more tests. (scalbln_test_data): Likewise. --- math/libm-test.inc | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'math') diff --git a/math/libm-test.inc b/math/libm-test.inc index 34f83c64f6..6d7ff12e04 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -9135,6 +9135,25 @@ static const struct test_fi_f_data scalbn_test_data[] = TEST_fi_f (scalbn, min_subnorm_value, MANT_DIG, min_value, NO_INEXACT_EXCEPTION), TEST_fi_f (scalbn, -min_subnorm_value, MANT_DIG, -min_value, NO_INEXACT_EXCEPTION), + TEST_fi_f (scalbn, min_value, -MANT_DIG, min_subnorm_value, NO_INEXACT_EXCEPTION), + TEST_fi_f (scalbn, -min_value, -MANT_DIG, -min_subnorm_value, NO_INEXACT_EXCEPTION), + TEST_fi_f (scalbn, min_value, -MANT_DIG-1, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value, -MANT_DIG-1, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value, -MANT_DIG-2, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value, -MANT_DIG-2, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value * 1.5, -MANT_DIG, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value * 1.5, -MANT_DIG, -min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value * 1.5, -MANT_DIG-1, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value * 1.5, -MANT_DIG-1, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value * 1.5, -MANT_DIG-2, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value * 1.5, -MANT_DIG-2, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value * 1.25, -MANT_DIG, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value * 1.25, -MANT_DIG, -min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value * 1.25, -MANT_DIG-1, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value * 1.25, -MANT_DIG-1, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, min_value * 1.25, -MANT_DIG-2, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, -min_value * 1.25, -MANT_DIG-2, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fi_f (scalbn, 1, INT_MAX, plus_oflow, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION), TEST_fi_f (scalbn, 1, INT_MIN, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), TEST_fi_f (scalbn, max_value, INT_MAX, plus_oflow, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION), @@ -9193,6 +9212,25 @@ static const struct test_fl_f_data scalbln_test_data[] = TEST_fl_f (scalbln, min_subnorm_value, MANT_DIG, min_value, NO_INEXACT_EXCEPTION), TEST_fl_f (scalbln, -min_subnorm_value, MANT_DIG, -min_value, NO_INEXACT_EXCEPTION), + TEST_fl_f (scalbln, min_value, -MANT_DIG, min_subnorm_value, NO_INEXACT_EXCEPTION), + TEST_fl_f (scalbln, -min_value, -MANT_DIG, -min_subnorm_value, NO_INEXACT_EXCEPTION), + TEST_fl_f (scalbln, min_value, -MANT_DIG-1, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value, -MANT_DIG-1, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value, -MANT_DIG-2, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value, -MANT_DIG-2, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value * 1.5, -MANT_DIG, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value * 1.5, -MANT_DIG, -min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value * 1.5, -MANT_DIG-1, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value * 1.5, -MANT_DIG-1, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value * 1.5, -MANT_DIG-2, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value * 1.5, -MANT_DIG-2, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value * 1.25, -MANT_DIG, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value * 1.25, -MANT_DIG, -min_subnorm_value * 2, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value * 1.25, -MANT_DIG-1, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, plus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value * 1.25, -MANT_DIG-1, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, -min_subnorm_value, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION, minus_zero, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, min_value * 1.25, -MANT_DIG-2, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, -min_value * 1.25, -MANT_DIG-2, minus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION), + TEST_fl_f (scalbln, 1, INT_MAX, plus_oflow, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_PLUS_OFLOW), TEST_fl_f (scalbln, 1, INT_MIN, plus_uflow, INEXACT_EXCEPTION|UNDERFLOW_EXCEPTION|ERRNO_PLUS_UFLOW), TEST_fl_f (scalbln, max_value, INT_MAX, plus_oflow, INEXACT_EXCEPTION|OVERFLOW_EXCEPTION|ERRNO_PLUS_OFLOW), -- cgit 1.4.1