Remove warning from clang.

2 files changed, 11 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index a98c2ba6..a6c5919d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-08-25         Pat Rankin            <r.pat.rankin@gmail.com>
+
+	* builtin.c (TYPE_MINIMUM): Use type uintmax_t for the calculation,
+	deferring the cast to the target type until the final result.
+
 2017-08-27         Juan Manuel Guerrero  <juan.guerrero@gmx.de>
 
 	* mbsupport.h [__DJGPP_]: Provide multi-byte specific declarations
diff --git a/builtin.c b/builtin.c
index bf838a8a..cd270e84 100644
--- a/builtin.c
+++ b/builtin.c
@@ -42,10 +42,13 @@
 
 /* The extra casts work around common compiler bugs.  */
 #define TYPE_SIGNED(t) (! ((t) 0 < (t) -1))
-/* The outer cast is needed to work around a bug in Cray C 5.0.3.0.
-   It is necessary at least when t == time_t.  */
+/* Note:  these assume that negative integers are represented internally
+   via 2's complement, which is not mandated by C.  They also ignore the
+   fact that signed integer arithmetic overflow can trigger exceptions,
+   unlike unsigned which is guaranteed not to do so. */
 #define TYPE_MINIMUM(t) ((t) (TYPE_SIGNED (t) \
-			      ? ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1) : (t) 0))
+			      ? ~ (uintmax_t) 0 << (sizeof (t) * CHAR_BIT - 1) \
+			      : 0))
 #define TYPE_MAXIMUM(t) ((t) (~ (t) 0 - TYPE_MINIMUM (t)))
 
 #ifndef INTMAX_MIN