Distinguish 'Fake' blank lines

Author: Camsyn

llvm/utils/UpdateTestChecks/common.py

@@ -2280,6 +2280,9 @@ def add_checks(
             # For IR output, change all defs to FileCheck variables, so we're immune
             # to variable naming fashions.
             else:
+                blank_line_indices = {
+                    i for i, line in enumerate(func_body) if line.strip() == ""
+                } if ginfo.get_version() >= 7 else set()
                 func_body = generalize_check_lines(
                     func_body,
                     ginfo,
@@ -2305,9 +2308,13 @@ def add_checks(
 
                 is_blank_line = False
 
-                for func_line in func_body:
+                for idx, func_line in enumerate(func_body):
                     if func_line.strip() == "":
-                        if ginfo.get_version() >= 7:
+                        # We should distinguish if the line is a 'fake' blank line generated by
+                        # generalize_check_lines removing comments.
+                        # Fortunately, generalize_check_lines does not change the index of each line,
+                        # we can record the indices of blank lines preemptively.
+                        if idx in blank_line_indices:
                             output_lines.append(
                                 "{} {}-EMPTY:".format(comment_marker, checkprefix)
                             )