diff --git a/utils/fpcmp/fpcmp.cpp b/utils/fpcmp/fpcmp.cpp
index ae5667a46d8..3df0fa5480c 100644
--- a/utils/fpcmp/fpcmp.cpp
+++ b/utils/fpcmp/fpcmp.cpp
@@ -56,7 +56,7 @@ static bool isNumberChar(char C) {
   switch (C) {
   case '0': case '1': case '2': case '3': case '4':
   case '5': case '6': case '7': case '8': case '9': 
-  case '.':
+  case '.': case '+': case '-':
   case 'e':
   case 'E': return true;
   default: return false;
@@ -64,7 +64,7 @@ static bool isNumberChar(char C) {
 }
 
 static char *BackupNumber(char *Pos, char *FirstChar) {
-  while (Pos < FirstChar && isNumberChar(Pos[-1]))
+  while (Pos > FirstChar && isNumberChar(Pos[-1]))
     --Pos;
   return Pos;
 }