From 53ba208c724637518a743169736ce7a25b285175 Mon Sep 17 00:00:00 2001
From: Eli Friedman <eli.friedman@gmail.com>
Date: Thu, 13 Oct 2011 22:49:56 +0000
Subject: [PATCH] Avoid undefined behavior in signed integer negation.  Patch
 by Ahmed Charles.

llvm-svn: 141905
---
 llvm/lib/Support/raw_ostream.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index c9cf249500d6..4927e9a7b9d4 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -121,7 +121,8 @@ raw_ostream &raw_ostream::operator<<(unsigned long N) {
 raw_ostream &raw_ostream::operator<<(long N) {
   if (N <  0) {
     *this << '-';
-    N = -N;
+    // Avoid undefined behavior on LONG_MIN with a cast.
+    N = -(unsigned long)N;
   }
 
   return this->operator<<(static_cast<unsigned long>(N));
-- 
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