!fixup address latest comments, thanks

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -1959,9 +1959,9 @@ class VPScalarPHIRecipe : public VPHeaderPHIRecipe {
 };
 
 /// A recipe for widened phis. Incoming values are operands of the recipe and
-/// their operand index corresponds to the incoming predeocessor block. If the
+/// their operand index corresponds to the incoming predecessor block. If the
 /// recipe is placed in an entry block to a (non-replicate) region, it must have
-/// exactly 2 incoming values, the first from the predecessors of the region and
+/// exactly 2 incoming values, the first from the predecessor of the region and
 /// the second from the exiting block of the region.
 class VPWidenPHIRecipe : public VPSingleDefRecipe {
 public:

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -3612,7 +3612,9 @@ void VPReductionPHIRecipe::print(raw_ostream &O, const Twine &Indent,
 VPBasicBlock *VPWidenPHIRecipe::getIncomingBlock(unsigned I) {
   VPBasicBlock *Parent = getParent();
   VPBlockBase *Pred = nullptr;
-  if (Parent->getNumPredecessors() == 0) {
+  if (Parent->getNumPredecessors() > 0) {
+    Pred = Parent->getPredecessors()[I];
+  } else {
     auto *Region = Parent->getParent();
     assert(Region && !Region->isReplicator() && Region->getEntry() == Parent &&
            "must be in the entry block of a non-replicate region");
@@ -3623,8 +3625,6 @@ VPBasicBlock *VPWidenPHIRecipe::getIncomingBlock(unsigned I) {
     // I ==  0 selects the predecessor of the region, I == 1 selects the region
     // itself whose exiting block feeds the phi across the backedge.
     Pred = I == 0 ? Region->getSinglePredecessor() : Region;
-  } else {
-    Pred = Parent->getPredecessors()[I];
   }
 
   return Pred->getExitingBasicBlock();

llvm/unittests/Transforms/Vectorize/VPlanTest.cpp

@@ -694,6 +694,7 @@ TEST_F(VPBasicBlockTest, reassociateBlocks) {
     IntegerType *Int32 = IntegerType::get(C, 32);
     VPValue *Val = Plan.getOrAddLiveIn(ConstantInt::get(Int32, 1));
     WidenPhi->addOperand(Val);
+    WidenPhi->addOperand(Val);
     VPBB2->appendRecipe(WidenPhi);
 
     VPBasicBlock *VPBBNew = Plan.createVPBasicBlock("VPBBNew");