Add Loop contains utility methods for testing whether a loop

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

diff --git a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index b717699b7e055cfcbbd13291a56191f692aa5c2c..846e432a7df33045496d709cc321533d7b9407f7 100644 (file)
--- a/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -29,10 +29,8 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/CFG.h"
-#include "llvm/Support/Compiler.h"
 #include <algorithm>
 using namespace llvm;
 
@@ -41,7 +39,6 @@ STATISTIC(NumSingleStore,   "Number of alloca's promoted with a single store");
 STATISTIC(NumDeadAlloca,    "Number of dead alloca's removed");
 STATISTIC(NumPHIInsert,     "Number of PHI nodes inserted");
 
-// Provide DenseMapInfo for all pointers.
 namespace llvm {
 template<>
 struct DenseMapInfo<std::pair<BasicBlock*, unsigned> > {
@@ -58,7 +55,6 @@ struct DenseMapInfo<std::pair<BasicBlock*, unsigned> > {
   static bool isEqual(const EltTy &LHS, const EltTy &RHS) {
     return LHS == RHS;
   }
-  static bool isPod() { return true; }
 };
 }
 
@@ -101,11 +97,11 @@ namespace {
   struct AllocaInfo;
 
   // Data package used by RenamePass()
-  class VISIBILITY_HIDDEN RenamePassData {
+  class RenamePassData {
   public:
     typedef std::vector<Value *> ValVector;
     
-    RenamePassData() {}
+    RenamePassData() : BB(NULL), Pred(NULL), Values() {}
     RenamePassData(BasicBlock *B, BasicBlock *P,
                    const ValVector &V) : BB(B), Pred(P), Values(V) {}
     BasicBlock *BB;
@@ -124,7 +120,7 @@ namespace {
   ///
   /// This functionality is important because it avoids scanning large basic
   /// blocks multiple times when promoting many allocas in the same block.
-  class VISIBILITY_HIDDEN LargeBlockInfo {
+  class LargeBlockInfo {
     /// InstNumbers - For each instruction that we track, keep the index of the
     /// instruction.  The index starts out as the number of the instruction from
     /// the start of the block.
@@ -171,7 +167,7 @@ namespace {
     }
   };
 
-  struct VISIBILITY_HIDDEN PromoteMem2Reg {
+  struct PromoteMem2Reg {
     /// Allocas - The alloca instructions being promoted.
     ///
     std::vector<AllocaInst*> Allocas;
@@ -181,7 +177,7 @@ namespace {
     /// AST - An AliasSetTracker object to update.  If null, don't update it.
     ///
     AliasSetTracker *AST;
-
+    
     /// AllocaLookup - Reverse mapping of Allocas.
     ///
     std::map<AllocaInst*, unsigned>  AllocaLookup;
@@ -291,10 +287,9 @@ namespace {
       // As we scan the uses of the alloca instruction, keep track of stores,
       // and decide whether all of the loads and stores to the alloca are within
       // the same basic block.
-      for (Value::use_iterator U = AI->use_begin(), E = AI->use_end();
-           U != E;)  {
-        Instruction *User = cast<Instruction>(*U);
-        ++U;
+      for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
+           UI != E;)  {
+        Instruction *User = cast<Instruction>(*UI++);
         if (BitCastInst *BC = dyn_cast<BitCastInst>(User)) {
           // Remove any uses of this alloca in DbgInfoInstrinsics.
           assert(BC->hasOneUse() && "Unexpected alloca uses!");
@@ -303,7 +298,8 @@ namespace {
           BC->eraseFromParent();
           continue;
         } 
-        else if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
+        
+        if (StoreInst *SI = dyn_cast<StoreInst>(User)) {
           // Remember the basic blocks which define new values for the alloca
           DefiningBlocks.push_back(SI->getParent());
           AllocaPointerVal = SI->getOperand(0);
@@ -491,17 +487,14 @@ void PromoteMem2Reg::run() {
       PHINode *PN = I->second;
       
       // If this PHI node merges one value and/or undefs, get the value.
-      if (Value *V = PN->hasConstantValue(true)) {
-        if (!isa<Instruction>(V) ||
-            properlyDominates(cast<Instruction>(V), PN)) {
-          if (AST && isa<PointerType>(PN->getType()))
-            AST->deleteValue(PN);
-          PN->replaceAllUsesWith(V);
-          PN->eraseFromParent();
-          NewPhiNodes.erase(I++);
-          EliminatedAPHI = true;
-          continue;
-        }
+      if (Value *V = PN->hasConstantValue(&DT)) {
+        if (AST && isa<PointerType>(PN->getType()))
+          AST->deleteValue(PN);
+        PN->replaceAllUsesWith(V);
+        PN->eraseFromParent();
+        NewPhiNodes.erase(I++);
+        EliminatedAPHI = true;
+        continue;
       }
       ++I;
     }
@@ -603,7 +596,9 @@ ComputeLiveInBlocks(AllocaInst *AI, AllocaInfo &Info,
         LiveInBlockWorklist.pop_back();
         --i, --e;
         break;
-      } else if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
+      }
+      
+      if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
         if (LI->getOperand(0) != AI) continue;
         
         // Okay, we found a load before a store to the alloca.  It is actually
@@ -749,7 +744,12 @@ void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI,
     }
     
     // Otherwise, we *can* safely rewrite this load.
-    LI->replaceAllUsesWith(OnlyStore->getOperand(0));
+    Value *ReplVal = OnlyStore->getOperand(0);
+    // If the replacement value is the load, this must occur in unreachable
+    // code.
+    if (ReplVal == LI)
+      ReplVal = UndefValue::get(LI->getType());
+    LI->replaceAllUsesWith(ReplVal);
     if (AST && isa<PointerType>(LI->getType()))
       AST->deleteValue(LI);
     LI->eraseFromParent();
@@ -757,6 +757,7 @@ void PromoteMem2Reg::RewriteSingleStoreAlloca(AllocaInst *AI,
   }
 }
 
+namespace {
 
 /// StoreIndexSearchPredicate - This is a helper predicate used to search by the
 /// first element of a pair.
@@ -767,6 +768,8 @@ struct StoreIndexSearchPredicate {
   }
 };
 
+}
+
 /// PromoteSingleBlockAlloca - Many allocas are only used within a single basic
 /// block.  If this is the case, avoid traversing the CFG and inserting a lot of
 /// potentially useless PHI nodes by just performing a single linear pass over
@@ -864,8 +867,8 @@ bool PromoteMem2Reg::QueuePhiNode(BasicBlock *BB, unsigned AllocaNo,
   // Create a PhiNode using the dereferenced type... and add the phi-node to the
   // BasicBlock.
   PN = PHINode::Create(Allocas[AllocaNo]->getAllocatedType(),
-                       Allocas[AllocaNo]->getName() + "." +
-                       utostr(Version++), BB->begin());
+                       Allocas[AllocaNo]->getName() + "." + Twine(Version++), 
+                       BB->begin());
   ++NumPHIInsert;
   PhiToAllocaMap[PN] = AllocaNo;
   PN->reserveOperandSpace(getNumPreds(BB));