diff --git a/tools/transforms/PNRegularExpressions.cpp b/tools/transforms/PNRegularExpressions.cpp
index 7bc5f2fc7913a3d3531dd7fe2f544c7a930bee24..261c54b1d23c8dadd538352a5479dd8fe4b77af9 100644
--- a/tools/transforms/PNRegularExpressions.cpp
+++ b/tools/transforms/PNRegularExpressions.cpp
@@ -16,7 +16,7 @@ PNRegularExpressions::PNRegularExpressions()
 	exit(1);
     }
 
-    if (regcomp(&regex_ret, "^ret$", REG_EXTENDED | REG_ICASE) != 0)
+    if (regcomp(&regex_ret, "^ret[[:blank:]]*$", REG_EXTENDED | REG_ICASE) != 0)
     {
 	fprintf(stderr,"Error: regular expression for ret failed to compile\n");
 	exit(1);