| Message ID | 20180509205205.GZ8577@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | Workaround glibc <= 2.23 nextafterl/nexttowardl bug (PR tree-optimization/85699) | expand |
On May 9, 2018 10:52:05 PM GMT+02:00, Jakub Jelinek <jakub@redhat.com> wrote: >Hi! > >glibc <= 2.23 has buggy nextafterl/nexttowardl as can be seen on the >nextafter-2.c testcase. > >Do we want to workaround this bug, e.g. with the following patch? Works for me. Was the reason to test the target libc to test the compare against arithmetic? Thanks, Richard. >Regtested on x86_64-linux (with glibc 2.26). Ok for trunk? > >2018-05-09 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/85699 > * gcc.dg/nextafter-1.c (NO_LONG_DOUBLE): Define if not defined. Use > !NO_LONG_DOUBLE instead of __LDBL_MANT_DIG__ != 106. > * gcc.dg/nextafter-2.c: Include stdlib.h. For glibc < 2.24 define > NO_LONG_DOUBLE to 1 before including nextafter-1.c. > >--- gcc/testsuite/gcc.dg/nextafter-1.c.jj 2018-05-06 23:12:48.952619545 >+0200 >+++ gcc/testsuite/gcc.dg/nextafter-1.c 2018-05-09 14:58:53.694198614 >+0200 >@@ -20,6 +20,9 @@ long double nexttowardl (long double, lo > #ifndef NEED_EXC > #define NEED_EXC 0 > #endif >+#ifndef NO_LONG_DOUBLE >+#define NO_LONG_DOUBLE (__LDBL_MANT_DIG__ == 106) >+#endif > > #define TEST(name, fn, type, L1, L2, l1, l2, MIN1, \ > MAX1, DENORM_MIN1, EPSILON1, MIN2, MAX2, DENORM_MIN2) \ >@@ -129,7 +132,7 @@ TEST (test1, nextafterf, float, F, F, f, > TEST (test2, nextafter, double, , , , , __DBL_MIN__, __DBL_MAX__, > __DBL_DENORM_MIN__, __DBL_EPSILON__, __DBL_MIN__, __DBL_MAX__, > __DBL_DENORM_MIN__) >-#if __LDBL_MANT_DIG__ != 106 >+#if !NO_LONG_DOUBLE >TEST (test3, nextafterl, long double, L, L, l, l, __LDBL_MIN__, >__LDBL_MAX__, > __LDBL_DENORM_MIN__, __LDBL_EPSILON__, __LDBL_MIN__, __LDBL_MAX__, > __LDBL_DENORM_MIN__) >@@ -149,7 +152,7 @@ main () > { > test1 (); > test2 (); >-#if __LDBL_MANT_DIG__ != 106 >+#if !NO_LONG_DOUBLE > test3 (); > test4 (); > test5 (); >--- gcc/testsuite/gcc.dg/nextafter-2.c.jj 2018-05-08 13:56:38.265930160 >+0200 >+++ gcc/testsuite/gcc.dg/nextafter-2.c 2018-05-09 14:59:45.527245803 >+0200 >@@ -5,4 +5,13 @@ > /* { dg-add-options ieee } */ > /* { dg-add-options c99_runtime } */ > >+#include <stdlib.h> >+ >+#if defined(__GLIBC__) && defined(__GLIBC_PREREQ) >+# if !__GLIBC_PREREQ (2, 24) >+/* Workaround buggy nextafterl in glibc 2.23 and earlier, >+ see https://sourceware.org/bugzilla/show_bug.cgi?id=20205 */ >+# define NO_LONG_DOUBLE 1 >+# endif >+#endif > #include "nextafter-1.c" > > Jakub
On Thu, May 10, 2018 at 07:53:15AM +0200, Richard Biener wrote: > On May 9, 2018 10:52:05 PM GMT+02:00, Jakub Jelinek <jakub@redhat.com> wrote: > >Hi! > > > >glibc <= 2.23 has buggy nextafterl/nexttowardl as can be seen on the > >nextafter-2.c testcase. > > > >Do we want to workaround this bug, e.g. with the following patch? > > Works for me. Was the reason to test the target libc to test the compare against arithmetic? Yes, to verify that the GCC implementation matches the libc one. Jakub
--- gcc/testsuite/gcc.dg/nextafter-1.c.jj 2018-05-06 23:12:48.952619545 +0200 +++ gcc/testsuite/gcc.dg/nextafter-1.c 2018-05-09 14:58:53.694198614 +0200 @@ -20,6 +20,9 @@ long double nexttowardl (long double, lo #ifndef NEED_EXC #define NEED_EXC 0 #endif +#ifndef NO_LONG_DOUBLE +#define NO_LONG_DOUBLE (__LDBL_MANT_DIG__ == 106) +#endif #define TEST(name, fn, type, L1, L2, l1, l2, MIN1, \ MAX1, DENORM_MIN1, EPSILON1, MIN2, MAX2, DENORM_MIN2) \ @@ -129,7 +132,7 @@ TEST (test1, nextafterf, float, F, F, f, TEST (test2, nextafter, double, , , , , __DBL_MIN__, __DBL_MAX__, __DBL_DENORM_MIN__, __DBL_EPSILON__, __DBL_MIN__, __DBL_MAX__, __DBL_DENORM_MIN__) -#if __LDBL_MANT_DIG__ != 106 +#if !NO_LONG_DOUBLE TEST (test3, nextafterl, long double, L, L, l, l, __LDBL_MIN__, __LDBL_MAX__, __LDBL_DENORM_MIN__, __LDBL_EPSILON__, __LDBL_MIN__, __LDBL_MAX__, __LDBL_DENORM_MIN__) @@ -149,7 +152,7 @@ main () { test1 (); test2 (); -#if __LDBL_MANT_DIG__ != 106 +#if !NO_LONG_DOUBLE test3 (); test4 (); test5 (); --- gcc/testsuite/gcc.dg/nextafter-2.c.jj 2018-05-08 13:56:38.265930160 +0200 +++ gcc/testsuite/gcc.dg/nextafter-2.c 2018-05-09 14:59:45.527245803 +0200 @@ -5,4 +5,13 @@ /* { dg-add-options ieee } */ /* { dg-add-options c99_runtime } */ +#include <stdlib.h> + +#if defined(__GLIBC__) && defined(__GLIBC_PREREQ) +# if !__GLIBC_PREREQ (2, 24) +/* Workaround buggy nextafterl in glibc 2.23 and earlier, + see https://sourceware.org/bugzilla/show_bug.cgi?id=20205 */ +# define NO_LONG_DOUBLE 1 +# endif +#endif #include "nextafter-1.c"