When mangling a negative number, remember that negating it does not
always yield a positive number.  Just print the negated result as an
unsigned number.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162163 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/ItaniumMangle.cpp b/lib/AST/ItaniumMangle.cpp
index 7c7a5e5..0b8a4c8 100644
--- a/lib/AST/ItaniumMangle.cpp
+++ b/lib/AST/ItaniumMangle.cpp
@@ -693,9 +693,10 @@
 void CXXNameMangler::mangleNumber(const llvm::APSInt &Value) {
   if (Value.isSigned() && Value.isNegative()) {
     Out << 'n';
-    Value.abs().print(Out, true);
-  } else
-    Value.print(Out, Value.isSigned());
+    Value.abs().print(Out, /*signed*/ false);
+  } else {
+    Value.print(Out, /*signed*/ false);
+  }
 }
 
 void CXXNameMangler::mangleNumber(int64_t Number) {