R600/SI: SI Control Flow Annotation bug fixed

Mixing of AddAvailableValue and GetValueAtEndOfBlock methods of SSAUpdater
leaded to the endless loop generation when the nested loops annotated.

This fixes a bug in the OCL_ML/KNN OpenCV test.  The test case is too
complex for FileCheck and would be very fragile.

Patch by: Elena Denisova

llvm-svn: 211374

llvm/lib/Target/R600/SIAnnotateControlFlow.cpp

@@ -65,7 +65,6 @@ class SIAnnotateControlFlow : public FunctionPass {
 
   DominatorTree *DT;
   StackVector Stack;
-  SSAUpdater PhiInserter;
 
   bool isTopOfStack(BasicBlock *BB);
 
@@ -81,7 +80,7 @@ class SIAnnotateControlFlow : public FunctionPass {
 
   void insertElse(BranchInst *Term);
 
-  void handleLoopCondition(Value *Cond);
+  Value *handleLoopCondition(Value *Cond, PHINode *Broken);
 
   void handleLoop(BranchInst *Term);
 
@@ -177,7 +176,7 @@ bool SIAnnotateControlFlow::isElse(PHINode *Phi) {
     } else {
       if (Phi->getIncomingValue(i) != BoolFalse)
         return false;
- 
+
     }
   }
   return true;
@@ -204,20 +203,26 @@ void SIAnnotateControlFlow::insertElse(BranchInst *Term) {
 }
 
 /// \brief Recursively handle the condition leading to a loop
-void SIAnnotateControlFlow::handleLoopCondition(Value *Cond) {
+Value *SIAnnotateControlFlow::handleLoopCondition(Value *Cond, PHINode *Broken) {
   if (PHINode *Phi = dyn_cast<PHINode>(Cond)) {
+    BasicBlock *Parent = Phi->getParent();
+    PHINode *NewPhi = PHINode::Create(Int64, 0, "", &Parent->front());
+    Value *Ret = NewPhi;
 
     // Handle all non-constant incoming values first
     for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
       Value *Incoming = Phi->getIncomingValue(i);
-      if (isa<ConstantInt>(Incoming))
+      BasicBlock *From = Phi->getIncomingBlock(i);
+      if (isa<ConstantInt>(Incoming)) {
+        NewPhi->addIncoming(Broken, From);
         continue;
+      }
 
       Phi->setIncomingValue(i, BoolFalse);
-      handleLoopCondition(Incoming);
+      Value *PhiArg = handleLoopCondition(Incoming, Broken);
+      NewPhi->addIncoming(PhiArg, From);
     }
 
-    BasicBlock *Parent = Phi->getParent();
     BasicBlock *IDom = DT->getNode(Parent)->getIDom()->getBlock();
 
     for (unsigned i = 0, e = Phi->getNumIncomingValues(); i != e; ++i) {
@@ -230,33 +235,28 @@ void SIAnnotateControlFlow::handleLoopCondition(Value *Cond) {
       if (From == IDom) {
         CallInst *OldEnd = dyn_cast<CallInst>(Parent->getFirstInsertionPt());
         if (OldEnd && OldEnd->getCalledFunction() == EndCf) {
-          Value *Args[] = {
-            OldEnd->getArgOperand(0),
-            PhiInserter.GetValueAtEndOfBlock(Parent)
-          };
-          Value *Ret = CallInst::Create(ElseBreak, Args, "", OldEnd);
-          PhiInserter.AddAvailableValue(Parent, Ret);
+          Value *Args[] = { OldEnd->getArgOperand(0), NewPhi };
+          Ret = CallInst::Create(ElseBreak, Args, "", OldEnd);
           continue;
         }
       }
-
       TerminatorInst *Insert = From->getTerminator();
-      Value *Arg = PhiInserter.GetValueAtEndOfBlock(From);
-      Value *Ret = CallInst::Create(Break, Arg, "", Insert);
-      PhiInserter.AddAvailableValue(From, Ret);
+      Value *PhiArg = CallInst::Create(Break, Broken, "", Insert);
+      NewPhi->setIncomingValue(i, PhiArg);
     }
     eraseIfUnused(Phi);
+    return Ret;
 
   } else if (Instruction *Inst = dyn_cast<Instruction>(Cond)) {
     BasicBlock *Parent = Inst->getParent();
     TerminatorInst *Insert = Parent->getTerminator();
-    Value *Args[] = { Cond, PhiInserter.GetValueAtEndOfBlock(Parent) };
-    Value *Ret = CallInst::Create(IfBreak, Args, "", Insert);
-    PhiInserter.AddAvailableValue(Parent, Ret);
+    Value *Args[] = { Cond, Broken };
+    return CallInst::Create(IfBreak, Args, "", Insert);
 
   } else {
     llvm_unreachable("Unhandled loop condition!");
   }
+  return 0;
 }
 
 /// \brief Handle a back edge (loop)
@@ -264,15 +264,11 @@ void SIAnnotateControlFlow::handleLoop(BranchInst *Term) {
   BasicBlock *Target = Term->getSuccessor(1);
   PHINode *Broken = PHINode::Create(Int64, 0, "", &Target->front());
 
-  PhiInserter.Initialize(Int64, "");
-  PhiInserter.AddAvailableValue(Target, Broken);
-
   Value *Cond = Term->getCondition();
   Term->setCondition(BoolTrue);
-  handleLoopCondition(Cond);
+  Value *Arg = handleLoopCondition(Cond, Broken);
 
   BasicBlock *BB = Term->getParent();
-  Value *Arg = PhiInserter.GetValueAtEndOfBlock(BB);
   for (pred_iterator PI = pred_begin(Target), PE = pred_end(Target);
        PI != PE; ++PI) {