Update to LLVM 3.5a.

Change-Id: Ifadecab779f128e62e430c2b4f6ddd84953ed617
diff --git a/lib/Transforms/Scalar/LoopRotation.cpp b/lib/Transforms/Scalar/LoopRotation.cpp
index 14c5655..fde6bac 100644
--- a/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/lib/Transforms/Scalar/LoopRotation.cpp
@@ -20,9 +20,10 @@
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/CFG.h"
+#include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IntrinsicInst.h"
-#include "llvm/Support/CFG.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Local.h"
@@ -43,8 +44,8 @@
     }
 
     // LCSSA form makes instruction renaming easier.
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
-      AU.addPreserved<DominatorTree>();
+    void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addPreserved<DominatorTreeWrapperPass>();
       AU.addRequired<LoopInfo>();
       AU.addPreserved<LoopInfo>();
       AU.addRequiredID(LoopSimplifyID);
@@ -55,7 +56,7 @@
       AU.addRequired<TargetTransformInfo>();
     }
 
-    bool runOnLoop(Loop *L, LPPassManager &LPM);
+    bool runOnLoop(Loop *L, LPPassManager &LPM) override;
     bool simplifyLoopLatch(Loop *L);
     bool rotateLoop(Loop *L, bool SimplifiedLatch);
 
@@ -78,6 +79,9 @@
 /// Rotate Loop L as many times as possible. Return true if
 /// the loop is rotated at least once.
 bool LoopRotate::runOnLoop(Loop *L, LPPassManager &LPM) {
+  if (skipOptnoneFunction(L))
+    return false;
+
   LI = &getAnalysis<LoopInfo>();
   TTI = &getAnalysis<TargetTransformInfo>();
 
@@ -130,7 +134,7 @@
     for (Value::use_iterator UI = OrigHeaderVal->use_begin(),
          UE = OrigHeaderVal->use_end(); UI != UE; ) {
       // Grab the use before incrementing the iterator.
-      Use &U = UI.getUse();
+      Use &U = *UI;
 
       // Increment the iterator before removing the use from the list.
       ++UI;
@@ -251,8 +255,9 @@
   // Nuke the Latch block.
   assert(Latch->empty() && "unable to evacuate Latch");
   LI->removeBlock(Latch);
-  if (DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>())
-    DT->eraseNode(Latch);
+  if (DominatorTreeWrapperPass *DTWP =
+          getAnalysisIfAvailable<DominatorTreeWrapperPass>())
+    DTWP->getDomTree().eraseNode(Latch);
   Latch->eraseFromParent();
   return true;
 }
@@ -301,7 +306,7 @@
     CodeMetrics Metrics;
     Metrics.analyzeBasicBlock(OrigHeader, *TTI);
     if (Metrics.notDuplicatable) {
-      DEBUG(dbgs() << "LoopRotation: NOT rotating - contains non duplicatable"
+      DEBUG(dbgs() << "LoopRotation: NOT rotating - contains non-duplicatable"
             << " instructions: "; L->dump());
       return false;
     }
@@ -433,23 +438,25 @@
     // The conditional branch can't be folded, handle the general case.
     // Update DominatorTree to reflect the CFG change we just made.  Then split
     // edges as necessary to preserve LoopSimplify form.
-    if (DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>()) {
+    if (DominatorTreeWrapperPass *DTWP =
+            getAnalysisIfAvailable<DominatorTreeWrapperPass>()) {
+      DominatorTree &DT = DTWP->getDomTree();
       // Everything that was dominated by the old loop header is now dominated
       // by the original loop preheader. Conceptually the header was merged
       // into the preheader, even though we reuse the actual block as a new
       // loop latch.
-      DomTreeNode *OrigHeaderNode = DT->getNode(OrigHeader);
+      DomTreeNode *OrigHeaderNode = DT.getNode(OrigHeader);
       SmallVector<DomTreeNode *, 8> HeaderChildren(OrigHeaderNode->begin(),
                                                    OrigHeaderNode->end());
-      DomTreeNode *OrigPreheaderNode = DT->getNode(OrigPreheader);
+      DomTreeNode *OrigPreheaderNode = DT.getNode(OrigPreheader);
       for (unsigned I = 0, E = HeaderChildren.size(); I != E; ++I)
-        DT->changeImmediateDominator(HeaderChildren[I], OrigPreheaderNode);
+        DT.changeImmediateDominator(HeaderChildren[I], OrigPreheaderNode);
 
-      assert(DT->getNode(Exit)->getIDom() == OrigPreheaderNode);
-      assert(DT->getNode(NewHeader)->getIDom() == OrigPreheaderNode);
+      assert(DT.getNode(Exit)->getIDom() == OrigPreheaderNode);
+      assert(DT.getNode(NewHeader)->getIDom() == OrigPreheaderNode);
 
       // Update OrigHeader to be dominated by the new header block.
-      DT->changeImmediateDominator(OrigHeader, OrigLatch);
+      DT.changeImmediateDominator(OrigHeader, OrigLatch);
     }
 
     // Right now OrigPreHeader has two successors, NewHeader and ExitBlock, and
@@ -459,9 +466,24 @@
     NewPH->setName(NewHeader->getName() + ".lr.ph");
 
     // Preserve canonical loop form, which means that 'Exit' should have only
-    // one predecessor.
-    BasicBlock *ExitSplit = SplitCriticalEdge(L->getLoopLatch(), Exit, this);
-    ExitSplit->moveBefore(Exit);
+    // one predecessor. Note that Exit could be an exit block for multiple
+    // nested loops, causing both of the edges to now be critical and need to
+    // be split.
+    SmallVector<BasicBlock *, 4> ExitPreds(pred_begin(Exit), pred_end(Exit));
+    bool SplitLatchEdge = false;
+    for (SmallVectorImpl<BasicBlock *>::iterator PI = ExitPreds.begin(),
+                                                 PE = ExitPreds.end();
+         PI != PE; ++PI) {
+      // We only need to split loop exit edges.
+      Loop *PredLoop = LI->getLoopFor(*PI);
+      if (!PredLoop || PredLoop->contains(Exit))
+        continue;
+      SplitLatchEdge |= L->getLoopLatch() == *PI;
+      BasicBlock *ExitSplit = SplitCriticalEdge(*PI, Exit, this);
+      ExitSplit->moveBefore(Exit);
+    }
+    assert(SplitLatchEdge &&
+           "Despite splitting all preds, failed to split latch exit?");
   } else {
     // We can fold the conditional branch in the preheader, this makes things
     // simpler. The first step is to remove the extra edge to the Exit block.
@@ -471,15 +493,17 @@
     PHBI->eraseFromParent();
 
     // With our CFG finalized, update DomTree if it is available.
-    if (DominatorTree *DT = getAnalysisIfAvailable<DominatorTree>()) {
+    if (DominatorTreeWrapperPass *DTWP =
+            getAnalysisIfAvailable<DominatorTreeWrapperPass>()) {
+      DominatorTree &DT = DTWP->getDomTree();
       // Update OrigHeader to be dominated by the new header block.
-      DT->changeImmediateDominator(NewHeader, OrigPreheader);
-      DT->changeImmediateDominator(OrigHeader, OrigLatch);
+      DT.changeImmediateDominator(NewHeader, OrigPreheader);
+      DT.changeImmediateDominator(OrigHeader, OrigLatch);
 
       // Brute force incremental dominator tree update. Call
       // findNearestCommonDominator on all CFG predecessors of each child of the
       // original header.
-      DomTreeNode *OrigHeaderNode = DT->getNode(OrigHeader);
+      DomTreeNode *OrigHeaderNode = DT.getNode(OrigHeader);
       SmallVector<DomTreeNode *, 8> HeaderChildren(OrigHeaderNode->begin(),
                                                    OrigHeaderNode->end());
       bool Changed;
@@ -492,11 +516,11 @@
           pred_iterator PI = pred_begin(BB);
           BasicBlock *NearestDom = *PI;
           for (pred_iterator PE = pred_end(BB); PI != PE; ++PI)
-            NearestDom = DT->findNearestCommonDominator(NearestDom, *PI);
+            NearestDom = DT.findNearestCommonDominator(NearestDom, *PI);
 
           // Remember if this changes the DomTree.
           if (Node->getIDom()->getBlock() != NearestDom) {
-            DT->changeImmediateDominator(BB, NearestDom);
+            DT.changeImmediateDominator(BB, NearestDom);
             Changed = true;
           }
         }