diff --git a/llvm/utils/chunk-print-before-all.py b/llvm/utils/chunk-print-before-all.py
--- a/llvm/utils/chunk-print-before-all.py
+++ b/llvm/utils/chunk-print-before-all.py
@@ -5,17 +5,13 @@
 # "crashinfo.txt" file leaving only the valid input IR in the last chunk.
 # Files are written to current working directory.
 
-from __future__ import print_function
-
 import sys
 
-basename = "chunk-"
 chunk_id = 0
 
-def print_chunk(lines):
+def print_chunk(lines, prefix, pass_name):
     global chunk_id
-    global basename
-    fname = basename + str(chunk_id) + ".ll"
+    fname = str(chunk_id) + "-" + prefix + "-" + pass_name + ".ll"
     chunk_id = chunk_id + 1
     print("writing chunk " + fname + " (" + str(len(lines)) + " lines)")
     with open(fname, "w") as f:
@@ -26,11 +22,29 @@
 for line in sys.stdin:
     if line.startswith("*** IR Dump Before "):
         if len(cur) != 0:
-            print_chunk(cur);
+            print_chunk(cur, "before", pass_name)
+            cur = []
+        cur.append("; " + line)
+        short_line = line[line.find("Before") + 7:]
+        if  short_line.find("<") == -1 or \
+            short_line.find("<") > short_line.find(" "):
+            pass_name = short_line[:short_line.find(" ")]
+        else:
+            pass_name = short_line[:short_line.find("<")]
+    elif line.startswith("*** IR Dump After "):
+        if len(cur) != 0:
+            print_chunk(cur, "after", pass_name)
             cur = []
         cur.append("; " + line)
+        short_line = line[line.find("After") + 6:]
+        if  short_line.find("<") == -1 or \
+            short_line.find("<") > short_line.find(" "):
+            pass_name = short_line[:short_line.find(" ")]
+        else:
+            pass_name = short_line[:short_line.find("<")]
+        
     elif line.startswith("Stack dump:"):
-        print_chunk(cur);
+        print_chunk(cur, "crash", pass_name);
         cur = []
         cur.append(line)
         is_dump = True
@@ -42,4 +56,4 @@
     with open("crashinfo.txt", "w") as f:
         f.writelines(cur)
 else:
-    print_chunk(cur);
+    print_chunk(cur, "last", pass_name);