[SROA] Fix the loop exit placement to be prior to indexing the splits

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

diff --git a/lib/Transforms/Scalar/StructurizeCFG.cpp b/lib/Transforms/Scalar/StructurizeCFG.cpp
index 8fd22681e5fc3ac3eafa8093ea0bdd073f52f242..7fe87f9319b6a164b1612cc0de2d3726c04132c9 100644 (file)
--- a/lib/Transforms/Scalar/StructurizeCFG.cpp
+++ b/lib/Transforms/Scalar/StructurizeCFG.cpp
@@ -7,10 +7,10 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "structurizecfg"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/MapVector.h"
 #include "llvm/ADT/SCCIterator.h"
+#include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/RegionInfo.h"
 #include "llvm/Analysis/RegionIterator.h"
 #include "llvm/Analysis/RegionPass.h"
@@ -21,6 +21,8 @@
 using namespace llvm;
 using namespace llvm::PatternMatch;
 
+#define DEBUG_TYPE "structurizecfg"
+
 namespace {
 
 // Definition of the complex types used in this pass.
@@ -64,14 +66,14 @@ public:
   /// \brief Start a new query
   NearestCommonDominator(DominatorTree *DomTree) {
     DT = DomTree;
-    Result = 0;
+    Result = nullptr;
   }
 
   /// \brief Add BB to the resulting dominator
   void addBlock(BasicBlock *BB, bool Remember = true) {
     DomTreeNode *Node = DT->getNode(BB);
 
-    if (Result == 0) {
+    if (!Result) {
       unsigned Numbering = 0;
       for (;Node;Node = Node->getIDom())
         IndexMap[Node] = ++Numbering;
@@ -165,6 +167,7 @@ class StructurizeCFG : public RegionPass {
   Region *ParentRegion;
 
   DominatorTree *DT;
+  LoopInfo *LI;
 
   RNVector Order;
   BBSet Visited;
@@ -246,6 +249,7 @@ public:
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequiredID(LowerSwitchID);
     AU.addRequired<DominatorTreeWrapperPass>();
+    AU.addRequired<LoopInfo>();
     AU.addPreserved<DominatorTreeWrapperPass>();
     RegionPass::getAnalysisUsage(AU);
   }
@@ -259,7 +263,7 @@ INITIALIZE_PASS_BEGIN(StructurizeCFG, "structurizecfg", "Structurize the CFG",
                       false, false)
 INITIALIZE_PASS_DEPENDENCY(LowerSwitch)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
-INITIALIZE_PASS_DEPENDENCY(RegionInfo)
+INITIALIZE_PASS_DEPENDENCY(RegionInfoPass)
 INITIALIZE_PASS_END(StructurizeCFG, "structurizecfg", "Structurize the CFG",
                     false, false)
 
@@ -279,7 +283,7 @@ bool StructurizeCFG::doInitialization(Region *R, RGPassManager &RGM) {
 void StructurizeCFG::orderNodes() {
   scc_iterator<Region *> I = scc_begin(ParentRegion);
   for (Order.clear(); !I.isAtEnd(); ++I) {
-    std::vector<RegionNode *> &Nodes = *I;
+    const std::vector<RegionNode *> &Nodes = *I;
     Order.append(Nodes.begin(), Nodes.end());
   }
 }
@@ -300,8 +304,9 @@ void StructurizeCFG::analyzeLoops(RegionNode *N) {
     for (unsigned i = 0, e = Term->getNumSuccessors(); i != e; ++i) {
       BasicBlock *Succ = Term->getSuccessor(i);
 
-      if (Visited.count(Succ))
+      if (Visited.count(Succ) && LI->isLoopHeader(Succ) ) {
         Loops[Succ] = BB;
+      }
     }
   }
 }
@@ -405,11 +410,11 @@ void StructurizeCFG::gatherPredicates(RegionNode *N) {
     } else {
 
       // It's an exit from a sub region
-      while(R->getParent() != ParentRegion)
+      while (R->getParent() != ParentRegion)
         R = R->getParent();
 
       // Edge from inside a subregion to its entry, ignore it
-      if (R == N)
+      if (*R == *N)
         continue;
 
       BasicBlock *Entry = R->getEntry();
@@ -453,10 +458,7 @@ void StructurizeCFG::insertConditions(bool Loops) {
   Value *Default = Loops ? BoolTrue : BoolFalse;
   SSAUpdater PhiInserter;
 
-  for (BranchVector::iterator I = Conds.begin(),
-       E = Conds.end(); I != E; ++I) {
-
-    BranchInst *Term = *I;
+  for (BranchInst *Term : Conds) {
     assert(Term->isConditional());
 
     BasicBlock *Parent = Term->getParent();
@@ -472,7 +474,7 @@ void StructurizeCFG::insertConditions(bool Loops) {
     NearestCommonDominator Dominator(DT);
     Dominator.addBlock(Parent, false);
 
-    Value *ParentValue = 0;
+    Value *ParentValue = nullptr;
     for (BBPredicates::iterator PI = Preds.begin(), PE = Preds.end();
          PI != PE; ++PI) {
 
@@ -591,7 +593,7 @@ void StructurizeCFG::changeExit(RegionNode *Node, BasicBlock *NewExit,
   if (Node->isSubRegion()) {
     Region *SubRegion = Node->getNodeAs<Region>();
     BasicBlock *OldExit = SubRegion->getExit();
-    BasicBlock *Dominator = 0;
+    BasicBlock *Dominator = nullptr;
 
     // Find all the edges from the sub region to the exit
     for (pred_iterator I = pred_begin(OldExit), E = pred_end(OldExit);
@@ -678,7 +680,8 @@ BasicBlock *StructurizeCFG::needPostfix(BasicBlock *Flow,
 
 /// \brief Set the previous node
 void StructurizeCFG::setPrevNode(BasicBlock *BB) {
-  PrevNode =  ParentRegion->contains(BB) ? ParentRegion->getBBNode(BB) : 0;
+  PrevNode = ParentRegion->contains(BB) ? ParentRegion->getBBNode(BB)
+                                        : nullptr;
 }
 
 /// \brief Does BB dominate all the predicates of Node ?
@@ -699,7 +702,7 @@ bool StructurizeCFG::isPredictableTrue(RegionNode *Node) {
   bool Dominated = false;
 
   // Regionentry is always true
-  if (PrevNode == 0)
+  if (!PrevNode)
     return true;
 
   for (BBPredicates::iterator I = Preds.begin(), E = Preds.end();
@@ -806,11 +809,11 @@ void StructurizeCFG::createFlow() {
   Conditions.clear();
   LoopConds.clear();
 
-  PrevNode = 0;
+  PrevNode = nullptr;
   Visited.clear();
 
   while (!Order.empty()) {
-    handleLoops(EntryDominatesExit, 0);
+    handleLoops(EntryDominatesExit, nullptr);
   }
 
   if (PrevNode)
@@ -863,6 +866,7 @@ bool StructurizeCFG::runOnRegion(Region *R, RGPassManager &RGM) {
   ParentRegion = R;
 
   DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  LI = &getAnalysis<LoopInfo>();
 
   orderNodes();
   collectInfos();