Add tests for the long double version of ecvt and fcvt

The test case misc/tst-efgcvt.c only tests the double variants of the
Old-fashioned System V number-to-string functions: ecvt, fcvt, and their
re-entrant counterparts.  With a few macros, the code can be reused for
the long double versions of these functions.  A future patch will reuse
it again for IEEE long double on powerpc64le.

Tested for powerpc and powerpc64le.

1 files changed, 36 insertions, 0 deletions

diff --git a/misc/tst-dbl-efgcvt.c b/misc/tst-dbl-efgcvt.c
new file mode 100644
index 0000000000..78accaddc7
--- /dev/null
+++ b/misc/tst-dbl-efgcvt.c
@@ -0,0 +1,36 @@
+/* Tests for *cvt function, double version.
+   Copyright (C) 1998-2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <float.h>
+
+#define ECVT ecvt
+#define FCVT fcvt
+#define ECVT_R ecvt_r
+#define FCVT_R fcvt_r
+#define FLOAT double
+#define PRINTF_CONVERSION "%f"
+
+#if DBL_MANT_DIG == 53
+# define EXTRA_ECVT_TESTS \
+  { 0x1p-1074, 3, -323, "494" }, \
+  { -0x1p-1074, 3, -323, "494" },
+#else
+# define EXTRA_ECVT_TESTS
+#endif
+
+#include <tst-efgcvt-template.c>