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?
Regtested on x86_64-linux (with glibc 2.26). Ok for trunk?
2018-05-09 Jakub Jelinek <ja...@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
