diff --git a/lib/MC/MCParser/AsmLexer.cpp b/lib/MC/MCParser/AsmLexer.cpp
index 7ca1cccc98c..867cb208cec 100644
--- a/lib/MC/MCParser/AsmLexer.cpp
+++ b/lib/MC/MCParser/AsmLexer.cpp
@@ -119,7 +119,7 @@ AsmToken AsmLexer::LexSlash() {
   switch (*CurPtr) {
   case '*': break; // C style comment.
   case '/': return ++CurPtr, LexLineComment();
-  default:  return AsmToken(AsmToken::Slash, StringRef(CurPtr, 1));
+  default:  return AsmToken(AsmToken::Slash, StringRef(CurPtr-1, 1));
   }
 
   // C Style comment.
diff --git a/test/MC/AsmParser/exprs.s b/test/MC/AsmParser/exprs.s
index 4e514032b6c..1cc96a3f418 100644
--- a/test/MC/AsmParser/exprs.s
+++ b/test/MC/AsmParser/exprs.s
@@ -19,9 +19,8 @@ k:
         check_expr +1, 1
         check_expr 1 + 2, 3
         check_expr 1 & 3, 1
-        // FIXME: There is a bug here in macro expansion.
-        .byte 4 / 2
-        .byte 4 / -2
+        check_expr 4 / 2, 2
+        check_expr 4 / -2, -2
         check_expr 1 == 1, 1
         check_expr 1 == 0, 0
         check_expr 1 > 0, 1