Replace some std::vectors that showed up in heap profiling with

[oota-llvm.git] / lib / CodeGen / UnreachableBlockElim.cpp

diff --git a/lib/CodeGen/UnreachableBlockElim.cpp b/lib/CodeGen/UnreachableBlockElim.cpp
index bcc124538d31c37b0ebc7d782158650ece079f55..3ba920204ac153918b89e707d5ed3d31bdfd7a98 100644 (file)
--- a/lib/CodeGen/UnreachableBlockElim.cpp
+++ b/lib/CodeGen/UnreachableBlockElim.cpp
@@ -1,12 +1,12 @@
 //===-- UnreachableBlockElim.cpp - Remove unreachable blocks for codegen --===//
-// 
+//
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-// 
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
 //===----------------------------------------------------------------------===//
-// 
+//
 // This pass is an extremely simple version of the SimplifyCFG pass.  Its sole
 // job is to delete LLVM basic blocks that are not reachable from the entry
 // node.  To do this, it performs a simple depth first traversal of the CFG,
@@ -21,19 +21,27 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/CodeGen/Passes.h"
+#include "llvm/Constant.h"
+#include "llvm/Instructions.h"
 #include "llvm/Function.h"
 #include "llvm/Pass.h"
+#include "llvm/Type.h"
 #include "llvm/Support/CFG.h"
-#include "Support/DepthFirstIterator.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/ADT/DepthFirstIterator.h"
 using namespace llvm;
 
 namespace {
-  class UnreachableBlockElim : public FunctionPass {
+  class VISIBILITY_HIDDEN UnreachableBlockElim : public FunctionPass {
     virtual bool runOnFunction(Function &F);
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    UnreachableBlockElim() : FunctionPass((intptr_t)&ID) {}
   };
-  RegisterOpt<UnreachableBlockElim>
-  X("unreachableblockelim", "Remove unreachable blocks from the CFG");
 }
+char UnreachableBlockElim::ID = 0;
+static RegisterPass<UnreachableBlockElim>
+X("unreachableblockelim", "Remove unreachable blocks from the CFG");
 
 FunctionPass *llvm::createUnreachableBlockEliminationPass() {
   return new UnreachableBlockElim();
@@ -52,10 +60,15 @@ bool UnreachableBlockElim::runOnFunction(Function &F) {
   std::vector<BasicBlock*> DeadBlocks;
   for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
     if (!Reachable.count(I)) {
-      DeadBlocks.push_back(I);
-      for (succ_iterator SI = succ_begin(&*I), E = succ_end(&*I); SI != E; ++SI)
-        (*SI)->removePredecessor(I);
-      I->dropAllReferences();
+      BasicBlock *BB = I;
+      DeadBlocks.push_back(BB);
+      while (PHINode *PN = dyn_cast<PHINode>(BB->begin())) {
+        PN->replaceAllUsesWith(Constant::getNullValue(PN->getType()));
+        BB->getInstList().pop_front();
+      }
+      for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
+        (*SI)->removePredecessor(BB);
+      BB->dropAllReferences();
     }
 
   if (DeadBlocks.empty()) return false;