Fixes a bug in pstat module

[apolyakov]

Summary

There was a bug in the pstat module: LNT crashes with
"UnboundLocalError: local variable 'list' referenced before assignment"
when trying to add linear regression to the regression graph.

[apolyakov]

@cmatthews can you please land the patch yourself? It seems that I don't have permission. Also, how can I get that permission (does it differ from llvm commit access)?

[apolyakov]

Gentle ping.

[hubert.reinterpretcast]

Committed in f5d76a0d510429bc5879398f6c7d3adcea8fd38b.

lnt/external/stats/pstat.py

 Returns: a list of lists as long as source, with source on the 'left' and
                  addon on the 'right'
 """
     if not isinstance(source, (list, tuple)):
         source = [source]
     if not isinstance(addon, (list, tuple)):
         addon = [addon]
     minlen = min(len(source), len(addon))
-    list = copy.deepcopy(source)                # start abut process
+    source_copy = copy.deepcopy(source)                # start abut process
     if not isinstance(source[0], (list, tuple)):
         if not isinstance(addon[0], (list, tuple)):
             for i in range(minlen):
-                list[i] = [source[i]] + [addon[i]]        # source/addon = column
+                source_copy[i] = [source[i]] + [addon[i]]        # source/addon = column
         else:
             for i in range(minlen):
-                list[i] = [source[i]] + addon[i]        # addon=list-of-lists
+                source_copy[i] = [source[i]] + addon[i]        # addon=list-of-lists
     else:
         if not isinstance(addon[0], (list, tuple)):
             for i in range(minlen):
-                list[i] = source[i] + [addon[i]]        # source=list-of-lists
+                source_copy[i] = source[i] + [addon[i]]        # source=list-of-lists
         else:
             for i in range(minlen):
-                list[i] = source[i] + addon[i]        # source/addon = list-of-lists
-    source = list
+                source_copy[i] = source[i] + addon[i]        # source/addon = list-of-lists
+    source = source_copy
     return source
 
 
 def colex (listoflists, cnums):
     """
 Extracts from listoflists the columns specified in the list 'cnums'
 (cnums can be an integer, a sequence of integers, or a string-expression that
 corresponds to a slice operation on the variable x ... e.g., 'x[3:]' will colex