minor tidying of comments.

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

diff --git a/lib/Transforms/Scalar/LoopUnswitch.cpp b/lib/Transforms/Scalar/LoopUnswitch.cpp
index 943c50f5f9257a738d4864f4f6c32e45eedf3021..955622e0256c2274efb090c3a29dc113b950680a 100644 (file)
--- a/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -54,11 +54,11 @@ STATISTIC(NumSelects , "Number of selects unswitched");
 STATISTIC(NumTrivial , "Number of unswitches that are trivial");
 STATISTIC(NumSimplify, "Number of simplifications of unswitched code");
 
-namespace {
-  cl::opt<unsigned>
-  Threshold("loop-unswitch-threshold", cl::desc("Max loop size to unswitch"),
-            cl::init(10), cl::Hidden);
+static cl::opt<unsigned>
+Threshold("loop-unswitch-threshold", cl::desc("Max loop size to unswitch"),
+          cl::init(10), cl::Hidden);
   
+namespace {
   class VISIBILITY_HIDDEN LoopUnswitch : public LoopPass {
     LoopInfo *LI;  // Loop information
     LPPassManager *LPM;
@@ -144,9 +144,9 @@ namespace {
                            std::vector<Instruction*> &Worklist, Loop *l);
     void RemoveLoopFromHierarchy(Loop *L);
   };
-  char LoopUnswitch::ID = 0;
-  RegisterPass<LoopUnswitch> X("loop-unswitch", "Unswitch loops");
 }
+char LoopUnswitch::ID = 0;
+static RegisterPass<LoopUnswitch> X("loop-unswitch", "Unswitch loops");
 
 LoopPass *llvm::createLoopUnswitchPass(bool Os) { 
   return new LoopUnswitch(Os); 
@@ -459,11 +459,11 @@ static inline void RemapInstruction(Instruction *I,
 // OrigPreheader is loop pre-header before this pass started
 // updating CFG. NewPrehader is loops new pre-header. However, after CFG
 // manipulation, loop L may not exist. So rely on input parameter NewPreheader.
-void CloneDomInfo(BasicBlock *NewBB, BasicBlock *Orig, 
-                  BasicBlock *NewPreheader, BasicBlock *OrigPreheader, 
-                  BasicBlock *OrigHeader,
-                  DominatorTree *DT, DominanceFrontier *DF,
-                  DenseMap<const Value*, Value*> &VM) {
+static void CloneDomInfo(BasicBlock *NewBB, BasicBlock *Orig,
+                         BasicBlock *NewPreheader, BasicBlock *OrigPreheader,
+                         BasicBlock *OrigHeader,
+                         DominatorTree *DT, DominanceFrontier *DF,
+                         DenseMap<const Value*, Value*> &VM) {
 
   // If NewBB alreay has found its place in domiantor tree then no need to do
   // anything.
@@ -569,7 +569,6 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
 
   // Insert the new branch.
   BranchInst::Create(TrueDest, FalseDest, BranchVal, InsertPt);
-
 }
 
 
@@ -607,6 +606,27 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond,
   // insert the new conditional branch.
   EmitPreheaderBranchOnCondition(Cond, Val, NewExit, NewPH, 
                                  OrigPH->getTerminator());
+  if (DT) {
+    DT->changeImmediateDominator(NewExit, OrigPH);
+    DT->changeImmediateDominator(NewPH, OrigPH);
+  }
+   
+  if (DF) {
+    // NewExit is now part of NewPH and Loop Header's dominance
+    // frontier.
+    DominanceFrontier::iterator  DFI = DF->find(NewPH);
+    if (DFI != DF->end())
+      DF->addToFrontier(DFI, NewExit);
+    DFI = DF->find(L->getHeader());
+    DF->addToFrontier(DFI, NewExit);
+
+    // ExitBlock does not have successors then NewExit is part of
+    // its dominance frontier.
+    if (succ_begin(ExitBlock) == succ_end(ExitBlock)) {
+      DFI = DF->find(ExitBlock);
+      DF->addToFrontier(DFI, NewExit);
+    }
+  }
   LPM->deleteSimpleAnalysisValue(OrigPH->getTerminator(), L);
   OrigPH->getTerminator()->eraseFromParent();
 
@@ -682,8 +702,7 @@ void LoopUnswitch::SplitExitEdges(Loop *L,
         InsertedPHIs.insert(NewLCSSA);
       }
 
-      BasicBlock::iterator InsertPt = EndBlock->begin();
-      while (dyn_cast<PHINode>(InsertPt)) ++InsertPt;
+      BasicBlock::iterator InsertPt = EndBlock->getFirstNonPHI();
       for (BasicBlock::iterator I = MiddleBlock->begin();
          (OldLCSSA = dyn_cast<PHINode>(I)) && InsertedPHIs.count(OldLCSSA) == 0;
          ++I) {
@@ -819,14 +838,10 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   }
 
   // Rewrite the code to refer to itself.
-  for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i) {
-    BasicBlock *NB = NewBlocks[i];
-    if (BasicBlock *UnwindDest = NB->getUnwindDest())
-      NB->setUnwindDest(cast<BasicBlock>(ValueMap[UnwindDest]));
-
-    for (BasicBlock::iterator I = NB->begin(), E = NB->end(); I != E; ++I)
+  for (unsigned i = 0, e = NewBlocks.size(); i != e; ++i)
+    for (BasicBlock::iterator I = NewBlocks[i]->begin(),
+           E = NewBlocks[i]->end(); I != E; ++I)
       RemapInstruction(I, ValueMap);
-  }
   
   // Rewrite the original preheader to select between versions of the loop.
   BranchInst *OldBR = cast<BranchInst>(OrigPreheader->getTerminator());