Change errs() to dbgs().

[oota-llvm.git] / lib / Transforms / Scalar / TailDuplication.cpp

diff --git a/lib/Transforms/Scalar/TailDuplication.cpp b/lib/Transforms/Scalar/TailDuplication.cpp
index d0998ab5a65d5984d7443985da79f179aa60e357..b06ae3def00ecf4484027b2fe23b637dc73ed67e 100644 (file)
--- a/lib/Transforms/Scalar/TailDuplication.cpp
+++ b/lib/Transforms/Scalar/TailDuplication.cpp
@@ -27,10 +27,11 @@
 #include "llvm/Pass.h"
 #include "llvm/Type.h"
 #include "llvm/Support/CFG.h"
+#include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Support/CommandLine.h"
-#include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include <map>
@@ -44,11 +45,11 @@ TailDupThreshold("taildup-threshold",
                  cl::init(1), cl::Hidden);
 
 namespace {
-  class VISIBILITY_HIDDEN TailDup : public FunctionPass {
+  class TailDup : public FunctionPass {
     bool runOnFunction(Function &F);
   public:
     static char ID; // Pass identification, replacement for typeid
-    TailDup() : FunctionPass((intptr_t)&ID) {}
+    TailDup() : FunctionPass(&ID) {}
 
   private:
     inline bool shouldEliminateUnconditionalBranch(TerminatorInst *, unsigned);
@@ -127,8 +128,8 @@ bool TailDup::shouldEliminateUnconditionalBranch(TerminatorInst *TI,
     // other instructions.
     if (isa<CallInst>(I) || isa<InvokeInst>(I)) return false;
 
-    // Allso alloca and malloc.
-    if (isa<AllocationInst>(I)) return false;
+    // Also alloca and malloc.
+    if (isa<AllocaInst>(I)) return false;
 
     // Some vector instructions can expand into a number of instructions.
     if (isa<ShuffleVectorInst>(I) || isa<ExtractElementInst>(I) ||
@@ -242,13 +243,13 @@ void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
   BasicBlock *DestBlock = Branch->getSuccessor(0);
   assert(SourceBlock != DestBlock && "Our predicate is broken!");
 
-  DOUT << "TailDuplication[" << SourceBlock->getParent()->getName()
-       << "]: Eliminating branch: " << *Branch;
+  DEBUG(errs() << "TailDuplication[" << SourceBlock->getParent()->getName()
+        << "]: Eliminating branch: " << *Branch);
 
   // See if we can avoid duplicating code by moving it up to a dominator of both
   // blocks.
   if (BasicBlock *DomBlock = FindObviousSharedDomOf(SourceBlock, DestBlock)) {
-    DOUT << "Found shared dominator: " << DomBlock->getName() << "\n";
+    DEBUG(errs() << "Found shared dominator: " << DomBlock->getName() << "\n");
 
     // If there are non-phi instructions in DestBlock that have no operands
     // defined in DestBlock, and if the instruction has no side effects, we can
@@ -257,7 +258,8 @@ void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
     while (!isa<TerminatorInst>(BBI)) {
       Instruction *I = BBI++;
 
-      bool CanHoist = !I->isTrapping() && !I->mayWriteToMemory();
+      bool CanHoist = I->isSafeToSpeculativelyExecute() &&
+                      !I->mayReadFromMemory();
       if (CanHoist) {
         for (unsigned op = 0, e = I->getNumOperands(); op != e; ++op)
           if (Instruction *OpI = dyn_cast<Instruction>(I->getOperand(op)))
@@ -270,7 +272,7 @@ void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
           // Remove from DestBlock, move right before the term in DomBlock.
           DestBlock->getInstList().remove(I);
           DomBlock->getInstList().insert(DomBlock->getTerminator(), I);
-          DOUT << "Hoisted: " << *I;
+          DEBUG(errs() << "Hoisted: " << *I);
         }
       }
     }
@@ -316,9 +318,12 @@ void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
   //
   BI = Branch; ++BI;  // Get an iterator to the first new instruction
   for (; BI != SourceBlock->end(); ++BI)
-    for (unsigned i = 0, e = BI->getNumOperands(); i != e; ++i)
-      if (Value *Remapped = ValueMapping[BI->getOperand(i)])
-        BI->setOperand(i, Remapped);
+    for (unsigned i = 0, e = BI->getNumOperands(); i != e; ++i) {
+      std::map<Value*, Value*>::const_iterator I =
+        ValueMapping.find(BI->getOperand(i));
+      if (I != ValueMapping.end())
+        BI->setOperand(i, I->second);
+    }
 
   // Next we check to see if any of the successors of DestBlock had PHI nodes.
   // If so, we need to add entries to the PHI nodes for SourceBlock now.
@@ -332,8 +337,9 @@ void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
       Value *IV = PN->getIncomingValueForBlock(DestBlock);
 
       // Remap the value if necessary...
-      if (Value *MappedIV = ValueMapping[IV])
-        IV = MappedIV;
+      std::map<Value*, Value*>::const_iterator I = ValueMapping.find(IV);
+      if (I != ValueMapping.end())
+        IV = I->second;
       PN->addIncoming(IV, SourceBlock);
     }
   }
@@ -348,10 +354,17 @@ void TailDup::eliminateUnconditionalBranch(BranchInst *Branch) {
   // instructions one last time, constant propagating and DCE'ing them, because
   // they may not be needed anymore.
   //
-  if (HadPHINodes)
-    while (BI != SourceBlock->end())
-      if (!dceInstruction(BI) && !doConstantPropagation(BI))
-        ++BI;
+  if (HadPHINodes) {
+    while (BI != SourceBlock->end()) {
+      Instruction *Inst = BI++;
+      if (isInstructionTriviallyDead(Inst))
+        Inst->eraseFromParent();
+      else if (Constant *C = ConstantFoldInstruction(Inst)) {
+        Inst->replaceAllUsesWith(C);
+        Inst->eraseFromParent();
+      }
+    }
+  }
 
   ++NumEliminated;  // We just killed a branch!
 }