From 9a5a5d1cb022aeeb07cc2640ec9c1ce0a59a0a2e Mon Sep 17 00:00:00 2001
From: Vladimir Marangozov <vladimir.marangozov@t-online.de>
Date: Wed, 12 Jul 2000 03:02:16 +0000
Subject: [PATCH] Checks whether right shift extends the sign bit.

Patch by Thomas Wouters <thomas@xs4all.net> with small changes of mine
(in main(), use return instead of exit).

Closes patch #100832
(but I can't assign it to myself, nor close it -- sorry)
---
 configure.in | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/configure.in b/configure.in
index 46dd5f1d2ef..763bfbde268 100644
--- a/configure.in
+++ b/configure.in
@@ -1136,6 +1136,19 @@ AC_MSG_RESULT($usable_wchar_t)
 # check for endianness
 AC_C_BIGENDIAN
 
+# Check whether right shifting a negative integer extends the sign bit
+# or fills with zeros (like the Cray J90, according to Tim Peters).
+AC_MSG_CHECKING(whether right shift extends the sign bit)
+AC_TRY_RUN([
+int main()
+{
+	return ((-1)>>3 == -1) ? 1 : 0;
+}
+],
+[AC_DEFINE(SIGNED_RIGHT_SHIFT_ZERO_FILLS)
+ AC_MSG_RESULT(yes)],
+[AC_MSG_RESULT(no)])
+
 # THIS MUST BE LAST, IT CAN BREAK OTHER TESTS!
 # Add sys/socket.h to confdefs.h
 cat >> confdefs.h <<\EOF