Fix dangerous memset on Candidate struct after placement new

Author: fridrich

runtime/compiler/optimizer/NewInitialization.cpp

@@ -442,8 +442,7 @@ bool TR_NewInitialization::findAllocationNode(TR::TreeTop *treeTop, TR::Node *no
 
     // An allocation node has been found. Create a new candidate entry.
     //
-    Candidate *candidate = new (trStackMemory()) Candidate;
-    memset(candidate, 0, sizeof(Candidate));
+    Candidate *candidate = new (trStackMemory()) Candidate();
     candidate->treeTop = treeTop;
     candidate->node = node;
     candidate->size = size;

runtime/compiler/optimizer/NewInitialization.hpp

@@ -65,6 +65,22 @@ class TR_NewInitialization : public TR::Optimization {
     };
 
     struct Candidate : public TR_Link<Candidate> {
+        Candidate()
+            : treeTop(NULL)
+            , node(NULL)
+            , uninitializedWords(NULL)
+            , initializedBytes(NULL)
+            , uninitializedBytes(NULL)
+            // localStores, localLoads, and inlinedCalls are automatically constructed
+            , size(0)
+            , startOffset(0)
+            , numUninitializedWords(0)
+            , numInitializedBytes(0)
+            , numUninitializedBytes(0)
+            , isArrayNew(false)
+            , isInSniffedMethod(false)
+        {}
+
         TR::TreeTop *treeTop;
         TR::Node *node;
         TR_BitVector *uninitializedWords;