Delete dead line

[oota-llvm.git] / lib / Transforms / Utils / Mem2Reg.cpp

diff --git a/lib/Transforms/Utils/Mem2Reg.cpp b/lib/Transforms/Utils/Mem2Reg.cpp
index 6bd859a4037baa0ac9a3032aad96c1286b1bd917..4d99280805822c24d361513f160c056b31e4e414 100644 (file)
--- a/lib/Transforms/Utils/Mem2Reg.cpp
+++ b/lib/Transforms/Utils/Mem2Reg.cpp
@@ -1,4 +1,11 @@
 //===- Mem2Reg.cpp - The -mem2reg pass, a wrapper around the Utils lib ----===//
+// 
+//                     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 pass is a simple pass wrapper around the PromoteMemToReg function call
 // exposed by the Utils library.
@@ -13,6 +20,8 @@
 #include "llvm/Target/TargetData.h"
 #include "Support/Statistic.h"
 
+namespace llvm {
+
 namespace {
   Statistic<> NumPromoted("mem2reg", "Number of alloca's promoted");
 
@@ -25,6 +34,7 @@ namespace {
     // getAnalysisUsage - We need dominance frontiers
     //
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<DominatorTree>();
       AU.addRequired<DominanceFrontier>();
       AU.addRequired<TargetData>();
       AU.setPreservesCFG();
@@ -38,21 +48,31 @@ bool PromotePass::runOnFunction(Function &F) {
   std::vector<AllocaInst*> Allocas;
   const TargetData &TD = getAnalysis<TargetData>();
 
-  BasicBlock &BB = F.getEntryNode();  // Get the entry node for the function
+  BasicBlock &BB = F.getEntryBlock();  // Get the entry node for the function
+
+  bool Changed  = false;
 
-  // Find allocas that are safe to promote, by looking at all instructions in
-  // the entry node
-  for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
-    if (AllocaInst *AI = dyn_cast<AllocaInst>(I))       // Is it an alloca?
-      if (isAllocaPromotable(AI, TD))
-        Allocas.push_back(AI);
+  DominatorTree     &DT = getAnalysis<DominatorTree>();
+  DominanceFrontier &DF = getAnalysis<DominanceFrontier>();
+  
+  while (1) {
+    Allocas.clear();
 
-  if (!Allocas.empty()) {
-    PromoteMemToReg(Allocas, getAnalysis<DominanceFrontier>(), TD);
+    // Find allocas that are safe to promote, by looking at all instructions in
+    // the entry node
+    for (BasicBlock::iterator I = BB.begin(), E = --BB.end(); I != E; ++I)
+      if (AllocaInst *AI = dyn_cast<AllocaInst>(I))       // Is it an alloca?
+        if (isAllocaPromotable(AI, TD))
+          Allocas.push_back(AI);
+
+    if (Allocas.empty()) break;
+
+    PromoteMemToReg(Allocas, DT, DF, TD);
     NumPromoted += Allocas.size();
-    return true;
+    Changed = true;
   }
-  return false;
+
+  return Changed;
 }
 
 // createPromoteMemoryToRegister - Provide an entry point to create this pass.
@@ -60,3 +80,5 @@ bool PromotePass::runOnFunction(Function &F) {
 Pass *createPromoteMemoryToRegister() {
   return new PromotePass();
 }
+
+} // End llvm namespace