From 98fb27a373f37554232e0060eef1a5bb00a07eb0 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Fri, 14 Mar 2014 12:27:52 -0500 Subject: [PATCH] PowerPC: remove wrong nearbyintl implementation for PPC64 The nearbyintl assembly implementation (sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S) returns wrong results for some inputs where first double is a exact integer and the precision is determined by second long double. Checking on implementation comments and history, I am very confident the assembly implementation was based on a version before commit 5c68d401698a58cf7da150d9cce769fa6679ba5f that fixes BZ#2423 (Errors in long double (ldbl-128ibm) rounding functions in glibc-2.4). By just removing the implementation and make the build select sysdeps/ieee754/ldbl-128ibm/s_nearbyintl.c instead fixes the failing math. Fixes BZ#16706. --- ChangeLog | 7 ++ NEWS | 2 +- math/libm-test.inc | 10 ++ sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S | 113 ------------------- 4 files changed, 18 insertions(+), 114 deletions(-) delete mode 100644 sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S diff --git a/ChangeLog b/ChangeLog index 5db859e476..f43bbf400e 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,10 @@ +2014-03-14 Adhemerval Zanella + + [BZ #16706] + * sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S: Remove wrong + implementation. + * math/libm-test.inc (nearbyint_test_data): Add more tests. + 2014-03-14 Adhemerval Zanella [BZ #16701] diff --git a/NEWS b/NEWS index 16a17c8af5..c9bfcb8b61 100644 --- a/NEWS +++ b/NEWS @@ -11,7 +11,7 @@ Version 2.20 15347, 15804, 15894, 16447, 16532, 16545, 16574, 16600, 16609, 16610, 16611, 16613, 16623, 16632, 16639, 16642, 16670, 16674, 16677, 16683, - 16689, 16695, 16701. + 16689, 16695, 16701, 16706. * The am33 port, which had not worked for several years, has been removed from ports. diff --git a/math/libm-test.inc b/math/libm-test.inc index c151b7d5f3..1d602eb805 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -9520,6 +9520,16 @@ static const struct test_f_f_data nearbyint_test_data[] = TEST_f_f (nearbyint, -281474976710656.75, -281474976710657.0, NO_INEXACT_EXCEPTION), TEST_f_f (nearbyint, -562949953421312.75, -562949953421313.0, NO_INEXACT_EXCEPTION), TEST_f_f (nearbyint, -1125899906842624.75, -1125899906842625.0, NO_INEXACT_EXCEPTION), +#endif +#ifdef TEST_LDOUBLE + /* Check cases where first double is a exact integer higher than 2^52 and + the precision is determined by second long double for IBM long double. */ + TEST_f_f (nearbyint, 34503599627370498.515625L, 34503599627370499.0L), + TEST_f_f (nearbyint, -34503599627370498.515625L, -34503599627370499.0L), +# if LDBL_MANT_DIG >= 106 + TEST_f_f (nearbyint, 1192568192774434123539907640624.484375L, 1192568192774434123539907640624.0L), + TEST_f_f (nearbyint, -1192568192774434123539907640624.484375L, -1192568192774434123539907640624.0L), +# endif #endif }; diff --git a/sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S b/sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S deleted file mode 100644 index acd95da82c..0000000000 --- a/sysdeps/powerpc/powerpc64/fpu/s_nearbyintl.S +++ /dev/null @@ -1,113 +0,0 @@ -/* nearbyint long double. - IBM extended format long double version. - Copyright (C) 2004-2014 Free Software Foundation, Inc. - This file is part of the GNU C Library. - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, see - . */ - -#include -#include - - .section ".toc","aw" -.LC0: /* 2**52 */ - .tc FD_43300000_0[TC],0x4330000000000000 - .section ".text" - -/* long double [fp1,fp2] nearbyintl (long double x [fp1,fp2]) - IEEE 1003.1 nearbyintl function. nearbyintl is similar to the rintl - but does raise the "inexact" exception. This implementation is - based on rintl but explicitly masks the inexact exception on entry - and clears any pending inexact before restoring the exception mask - on exit. - - PowerPC64 long double uses the IBM extended format which is - represented two 64-floating point double values. The values are - non-overlapping giving an effective precision of 106 bits. The first - double contains the high order bits of mantissa and is always rounded - to represent a normal rounding of long double to double. Since the - long double value is sum of the high and low values, the low double - normally has the opposite sign to compensate for the this rounding. - - For long double there are two cases: - 1) |x| < 2**52, all the integer bits are in the high double. - floor the high double and set the low double to -0.0. - 2) |x| >= 2**52, Rounding involves both doubles. - See the comment before label .L2 for details. - */ -ENTRY (__nearbyintl) - mffs fp11 /* Save current FPSCR. */ - lfd fp13,.LC0@toc(2) - fabs fp0,fp1 - mtfsb0 28 /* Disable "inexact" exceptions. */ - fsub fp12,fp13,fp13 /* generate 0.0 */ - fabs fp9,fp2 - fcmpu cr7,fp0,fp13 /* if (fabs(x) > TWO52) */ - fcmpu cr6,fp1,fp12 /* if (x > 0.0) */ - bnl- cr7,.L2 - fmr fp2,fp12 - bng- cr6,.L4 - fadd fp1,fp1,fp13 /* x+= TWO52; */ - fsub fp1,fp1,fp13 /* x-= TWO52; */ - b .L9 -.L4: - bnl- cr6,.L9 /* if (x < 0.0) */ - fsub fp1,fp13,fp1 /* x = TWO52 - x; */ - fsub fp0,fp1,fp13 /* x = - (x - TWO52); */ - fneg fp1,fp0 -.L9: - mtfsb0 6 /* Clear any pending "inexact" exceptions. */ - mtfsf 0x01,fp11 /* restore exception mask. */ - blr - -/* The high double is > TWO52 so we need to round the low double and - perhaps the high double. This gets a bit tricky so we use the - following algorithm: - - tau = floor(x_high/TWO52); - x0 = x_high - tau; - x1 = x_low + tau; - r1 = nearbyint(x1); - y_high = x0 + r1; - y_low = r1 - tau; - return y; */ -.L2: - fcmpu cr7,fp9,fp13 /* if (|x_low| > TWO52) */ - fcmpu cr0,fp9,fp12 /* || (|x_low| == 0.0) */ - bge- cr7,.L9 /* return x; */ - beq- cr0,.L9 - fdiv fp8,fp1,fp13 /* x_high/TWO52 */ - fctidz fp0,fp8 - fcfid fp8,fp0 /* tau = floor(x_high/TWO52); */ - fsub fp3,fp1,fp8 /* x0 = x_high - tau; */ - fadd fp4,fp2,fp8 /* x1 = x_low + tau; */ - - fcmpu cr6,fp4,fp12 /* if (x1 > 0.0) */ - bng- cr6,.L8 - fadd fp5,fp4,fp13 /* r1 = x1 + TWO52; */ - fsub fp5,fp5,fp13 /* r1 = r1 - TWO52; */ - b .L6 -.L8: - fmr fp5,fp4 - bge- cr6,.L6 /* if (x1 < 0.0) */ - fsub fp5,fp13,fp4 /* r1 = TWO52 - x1; */ - fsub fp0,fp5,fp13 /* r1 = - (r1 - TWO52); */ - fneg fp5,fp0 -.L6: - fadd fp1,fp3,fp5 /* y_high = x0 + r1; */ - fsub fp2,fp5,fp8 /* y_low = r1 - tau; */ - b .L9 -END (__nearbyintl) - -long_double_symbol (libm, __nearbyintl, nearbyintl) -- 2.43.5