In order for parameter attribute uniquing to make
any sense it is important that ParamAttr::None gets
treated the same as not supplying an attribute at
all.  Rather than stripping ParamAttr::None out of
the list of attributes, assert if ParamAttr::None
is seen.  Fix up the bitcode reader which liked to
insert ParamAttr::None all over the place.  Patch
based on one by Török Edwin.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44250 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index aa78e7c..119a583 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -232,17 +232,15 @@
       if (Record.size() & 1)
         return Error("Invalid ENTRY record");
 
-      ParamAttrsWithIndex PAWI;
       for (unsigned i = 0, e = Record.size(); i != e; i += 2) {
-        PAWI.index = Record[i];
-        PAWI.attrs = Record[i+1];
-        Attrs.push_back(PAWI);
+        if (Record[i+1] != ParamAttr::None)
+          Attrs.push_back(ParamAttrsWithIndex::get(Record[i], Record[i+1]));
       }
-      ParamAttrs.push_back(ParamAttrsList::get(Attrs));
+      ParamAttrs.push_back(Attrs.empty() ? NULL : ParamAttrsList::get(Attrs));
       Attrs.clear();
       break;
     }
-    }    
+    }
   }
 }