* Make some methods more const correct.
* Change the FunctionCalls and AuxFunctionCalls vectors into std::lists.
  This makes many operations on these lists much more natural, and avoids
  *exteremely* expensive copying of DSCallSites (e.g. moving nodes around
  between lists, erasing a node from not the end of the vector, etc).

With a profile build of analyze, this speeds up BU DS from 25.14s to
12.59s on 176.gcc.  I expect that it would help TD even more, but I don't
have data for it.

This effectively eliminates removeIdenticalCalls and children from the
profile, going from 6.53 to 0.27s.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19939 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/DataStructure/Steensgaard.cpp b/lib/Analysis/DataStructure/Steensgaard.cpp
index 5102ddd..eee9b0b 100644
--- a/lib/Analysis/DataStructure/Steensgaard.cpp
+++ b/lib/Analysis/DataStructure/Steensgaard.cpp
@@ -152,15 +152,15 @@
   // Now that we have all of the graphs inlined, we can go about eliminating
   // call nodes...
   //
-  std::vector<DSCallSite> &Calls =
-    ResultGraph->getAuxFunctionCalls();
+  std::list<DSCallSite> &Calls = ResultGraph->getAuxFunctionCalls();
   assert(Calls.empty() && "Aux call list is already in use??");
 
-  // Start with a copy of the original call sites...
+  // Start with a copy of the original call sites.
   Calls = ResultGraph->getFunctionCalls();
 
-  for (unsigned i = 0; i != Calls.size(); ) {
-    DSCallSite &CurCall = Calls[i];
+  for (std::list<DSCallSite>::iterator CI = Calls.begin(), E = Calls.end();
+       CI != E;) {
+    DSCallSite &CurCall = *CI++;
     
     // Loop over the called functions, eliminating as many as possible...
     std::vector<GlobalValue*> CallTargets;
@@ -185,10 +185,9 @@
     }
 
     if (CallTargets.empty()) {        // Eliminated all calls?
-      CurCall = Calls.back();         // Remove entry
-      Calls.pop_back();
-    } else
-      ++i;                            // Skip this call site...
+      std::list<DSCallSite>::iterator I = CI;
+      Calls.erase(--I);               // Remove entry
+    }
   }
 
   RetValMap.clear();