* expm1l: Fix configure test result with GCC 10 on powerpc64le
@ 2021-01-24 8:05 Bruno Haible
0 siblings, 0 replies; only message in thread
From: Bruno Haible @ 2021-01-24 8:05 UTC (permalink / raw)
To: bug-gnulib
On Alpine Linux 3.13/powerpc64le, configure reports
checking whether expm1l works... no
but the function in fact works. The issue is caused by a GCC optimization.
This patch fixes it.
2021-01-24 Bruno Haible <bruno@clisp.org>
expm1l: Fix configure test result with GCC 10 on powerpc64le.
* m4/expm1l.m4 (gl_FUNC_EXPM1L): Change test to avoid GCC optimization.
diff --git a/m4/expm1l.m4 b/m4/expm1l.m4
index 0eaaf84..8fe31b5 100644
--- a/m4/expm1l.m4
+++ b/m4/expm1l.m4
@@ -1,4 +1,4 @@
-# expm1l.m4 serial 7
+# expm1l.m4 serial 8
dnl Copyright (C) 2010-2021 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
@@ -134,7 +134,8 @@ int main (int argc, char *argv[])
long double x = 11.358L;
long double y = my_expm1l (x);
long double z = my_expm1l (- x);
- long double err = (y + (1.0L + y) * z) * TWO_LDBL_MANT_DIG;
+ volatile long double t = (1.0L + y) * z;
+ long double err = (y + t) * TWO_LDBL_MANT_DIG;
if (!(err >= -100.0L && err <= 100.0L))
result |= 1;
}
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