[LV] Move code from widenSelectInstruction to VPWidenSelectRecipe. (NFC)

[fhahn]

Summary

The code in widenSelectInstruction has already been transitioned
to only rely on information provided by VPWidenSelectRecipe directly.

Moving the code directly to VPWidenSelectRecipe::execute completes
the transition for the recipe.

It provides the following advantages:

1. Less indirection, easier to see what's going on.
2. Removes accesses to fields of ILV.

2. in particular ensures that no dependencies on

fields in ILV for vector code generation are re-introduced.

[fhahn]

rebased after 4348cd42c385

[Ayal]

Nice inlining!

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

public:
   /// loop.
   /// In the case of epilogue vectorization, this function is overriden to
   /// handle the more complex control flow around the loops.
   virtual BasicBlock *createVectorizedLoopSkeleton();
 
   void widenCallInstruction(CallInst &I, VPValue *Def, VPUser &ArgOperands,
                             VPTransformState &State);
 
-  /// Widen a single select instruction within the innermost loop.
-  void widenSelectInstruction(SelectInst &I, VPValue *VPDef, VPUser &Operands,
-                              bool InvariantCond, VPTransformState &State);
-
   /// Fix the vectorized code, taking care of header phi's, live-outs, and more.
   void fixVectorizedLoop(VPTransformState &State);
 
   // Return true if any runtime check is added.
   bool areSafetyChecksAdded() { return AddedSafetyChecks; }
 
   /// A type for vectorized values in the new loop. Each value from the
   /// original loop, when vectorized, is represented by UF vector values in the
#endif
       if (isa<FPMathOperator>(V))
         V->copyFastMathFlags(CI);
 
       State.set(Def, V, Part);
       addMetadata(V, &I);
   }
 }
 
-void InnerLoopVectorizer::widenSelectInstruction(SelectInst &I, VPValue *VPDef,
-                                                 VPUser &Operands,
-                                                 bool InvariantCond,
-                                                 VPTransformState &State) {
-  setDebugLocFromInst(&I);
-
-  // The condition can be loop invariant  but still defined inside the
-  // loop. This means that we can't just use the original 'cond' value.
-  // We have to take the 'vectorized' value and pick the first lane.
-  // Instcombine will make this a no-op.
-  auto *InvarCond = InvariantCond
-                        ? State.get(Operands.getOperand(0), VPIteration(0, 0))
-                        : nullptr;
-
-  for (unsigned Part = 0; Part < UF; ++Part) {
-    Value *Cond =
-        InvarCond ? InvarCond : State.get(Operands.getOperand(0), Part);
-    Value *Op0 = State.get(Operands.getOperand(1), Part);
-    Value *Op1 = State.get(Operands.getOperand(2), Part);
-    Value *Sel = Builder.CreateSelect(Cond, Op0, Op1);
-    State.set(VPDef, Sel, Part);
-    addMetadata(Sel, &I);
-  }
-}
-
 void LoopVectorizationCostModel::collectLoopScalars(ElementCount VF) {
   // We should not collect Scalars more than once per VF. Right now, this
   // function is called from collectUniformsAndScalars(), which already does
   // this check. Collecting Scalars for VF=1 does not make any sense.
   assert(VF.isVector() && Scalars.find(VF) == Scalars.end() &&
          "This function should not be visited twice for the same VF");
 
   SmallSetVector<Instruction *, 8> Worklist;

 #endif
 
 void VPWidenCallRecipe::execute(VPTransformState &State) {
   State.ILV->widenCallInstruction(*cast<CallInst>(getUnderlyingInstr()), this,
                                   *this, State);
 }
 
 void VPWidenSelectRecipe::execute(VPTransformState &State) {
-  State.ILV->widenSelectInstruction(*cast<SelectInst>(getUnderlyingInstr()),
-                                    this, *this, InvariantCond, State);
+  auto &I = *cast<SelectInst>(getUnderlyingInstr());
+  State.ILV->setDebugLocFromInst(&I);
+
+  // The condition can be loop invariant  but still defined inside the
+  // loop. This means that we can't just use the original 'cond' value.
+  // We have to take the 'vectorized' value and pick the first lane.
+  // Instcombine will make this a no-op.
+  auto *InvarCond =
+      InvariantCond ? State.get(getOperand(0), VPIteration(0, 0)) : nullptr;
+
+  for (unsigned Part = 0; Part < State.UF; ++Part) {
+    Value *Cond = InvarCond ? InvarCond : State.get(getOperand(0), Part);
+    Value *Op0 = State.get(getOperand(1), Part);
+    Value *Op1 = State.get(getOperand(2), Part);
+    Value *Sel = State.Builder.CreateSelect(Cond, Op0, Op1);
+    State.set(this, Sel, Part);
+    State.ILV->addMetadata(Sel, &I);
+  }
 }
 
 void VPWidenRecipe::execute(VPTransformState &State) {
   auto &I = *cast<Instruction>(getUnderlyingValue());
   auto &Builder = State.Builder;
   switch (I.getOpcode()) {
   case Instruction::Call:
   case Instruction::Br: