# HG changeset patch
# User Bruno Haible <bruno@clisp.org>
# Date 1293850488 -3600
# Node ID ca85283acd034c31c42376fe14103f3edcb493b7
# Parent  081ce9a593c4e3faf1c81de1aae2c54108fd61ac
isfinite: Avoid compiler bug of "cc -O" on HP-UX 11.11.

* lib/isfinite.c (zerof, zerod, zerol): New variables.
(gl_isfinitef, gl_isfinited, gl_isfinitel): Use them instead of literal
zero.

diff --git a/ChangeLog b/ChangeLog
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2010-12-31  Bruno Haible  <bruno@clisp.org>
+
+	isfinite: Avoid compiler bug of "cc -O" on HP-UX 11.11.
+	* lib/isfinite.c (zerof, zerod, zerol): New variables.
+	(gl_isfinitef, gl_isfinited, gl_isfinitel): Use them instead of literal
+	zero.
+
 2010-12-31  Bruno Haible  <bruno@clisp.org>
 
 	pwrite: Work around HP-UX 11.11 bug.
diff --git a/lib/isfinite.c b/lib/isfinite.c
--- a/lib/isfinite.c
+++ b/lib/isfinite.c
@@ -23,17 +23,30 @@
 #include "isnand-nolibm.h"
 #include "isnanl-nolibm.h"
 
+/* The "cc" compiler on HP-UX 11.11, when optimizing, simplifies the test
+   x - y == 0.0  to  x == y, a simplification which is invalid when x and y
+   are Infinity.  Disable this optimization.  */
+#if defined __hpux && !defined __GNUC__
+static float zerof;
+static double zerod;
+static long double zerol;
+#else
+# define zerof 0.f
+# define zerod 0.
+# define zerol 0.L
+#endif
+
 int gl_isfinitef (float x)
 {
-  return !isnanf (x) && x - x == 0.f;
+  return !isnanf (x) && x - x == zerof;
 }
 
 int gl_isfinited (double x)
 {
-  return !isnand (x) && x - x == 0.;
+  return !isnand (x) && x - x == zerod;
 }
 
 int gl_isfinitel (long double x)
 {
-  return !isnanl (x) && x - x == 0.L;
+  return !isnanl (x) && x - x == zerol;
 }