[LV] Move getBroadcastInstr to VPTransformState.::get (NFCI).

getBroadcastInstrs is only used in VPTransformState::get. Move it closer
to use to reduce unnecessary interaction with ILV object.

Author: fhahn

llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

@@ -577,13 +577,6 @@ class InnerLoopVectorizer {
   /// able to vectorize with strict in-order reductions for the given RdxDesc.
   bool useOrderedReductions(const RecurrenceDescriptor &RdxDesc);
 
-  /// Create a broadcast instruction. This method generates a broadcast
-  /// instruction (shuffle) for loop invariant values and for the induction
-  /// value. If this is the induction variable then we extend it to N, N+1, ...
-  /// this is needed because each iteration in the loop corresponds to a SIMD
-  /// element.
-  virtual Value *getBroadcastInstrs(Value *V);
-
   // Returns the resume value (bc.merge.rdx) for a reduction as
   // generated by fixReduction.
   PHINode *getReductionResumeValue(const RecurrenceDescriptor &RdxDesc);
@@ -820,9 +813,6 @@ class InnerLoopUnroller : public InnerLoopVectorizer {
                             ElementCount::getFixed(1),
                             ElementCount::getFixed(1), UnrollFactor, LVL, CM,
                             BFI, PSI, Check) {}
-
-private:
-  Value *getBroadcastInstrs(Value *V) override;
 };
 
 /// Encapsulate information regarding vectorization of a loop and its epilogue.
@@ -2266,25 +2256,6 @@ static void collectSupportedLoops(Loop &L, LoopInfo *LI,
 // LoopVectorizationCostModel and LoopVectorizationPlanner.
 //===----------------------------------------------------------------------===//
 
-Value *InnerLoopVectorizer::getBroadcastInstrs(Value *V) {
-  // We need to place the broadcast of invariant variables outside the loop,
-  // but only if it's proven safe to do so. Else, broadcast will be inside
-  // vector loop body.
-  Instruction *Instr = dyn_cast<Instruction>(V);
-  bool SafeToHoist = OrigLoop->isLoopInvariant(V) &&
-                     (!Instr ||
-                      DT->dominates(Instr->getParent(), LoopVectorPreHeader));
-  // Place the code for broadcasting invariant variables in the new preheader.
-  IRBuilder<>::InsertPointGuard Guard(Builder);
-  if (SafeToHoist)
-    Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
-
-  // Broadcast the scalar into all locations in the vector.
-  Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast");
-
-  return Shuf;
-}
-
 /// This function adds
 /// (StartIdx * Step, (StartIdx + 1) * Step, (StartIdx + 2) * Step, ...)
 /// to each vector element of Val. The sequence starts at StartIndex.
@@ -7849,8 +7820,6 @@ void LoopVectorizationPlanner::printPlans(raw_ostream &O) {
 }
 #endif
 
-Value *InnerLoopUnroller::getBroadcastInstrs(Value *V) { return V; }
-
 //===--------------------------------------------------------------------===//
 // EpilogueVectorizerMainLoop
 //===--------------------------------------------------------------------===//
@@ -9881,9 +9850,29 @@ Value *VPTransformState::get(VPValue *Def, unsigned Part) {
   if (hasVectorValue(Def, Part))
     return Data.PerPartOutput[Def][Part];
 
+  auto GetBroadcastInstrs = [this, Def](Value *V) {
+    bool SafeToHoist = Def->isDefinedOutsideVectorRegions();
+    if (VF.isScalar())
+      return V;
+    // Place the code for broadcasting invariant variables in the new preheader.
+    IRBuilder<>::InsertPointGuard Guard(Builder);
+    if (SafeToHoist) {
+      BasicBlock *LoopVectorPreHeader = CFG.VPBB2IRBB[cast<VPBasicBlock>(
+          Plan->getVectorLoopRegion()->getSinglePredecessor())];
+      if (LoopVectorPreHeader)
+        Builder.SetInsertPoint(LoopVectorPreHeader->getTerminator());
+    }
+
+    // Place the code for broadcasting invariant variables in the new preheader.
+    // Broadcast the scalar into all locations in the vector.
+    Value *Shuf = Builder.CreateVectorSplat(VF, V, "broadcast");
+
+    return Shuf;
+  };
+
   if (!hasScalarValue(Def, {Part, 0})) {
     Value *IRV = Def->getLiveInIRValue();
-    Value *B = ILV->getBroadcastInstrs(IRV);
+    Value *B = GetBroadcastInstrs(IRV);
     set(Def, B, Part);
     return B;
   }
@@ -9930,7 +9919,7 @@ Value *VPTransformState::get(VPValue *Def, unsigned Part) {
   // State, we will only generate the insertelements once.
   Value *VectorValue = nullptr;
   if (IsUniform) {
-    VectorValue = ILV->getBroadcastInstrs(ScalarValue);
+    VectorValue = GetBroadcastInstrs(ScalarValue);
     set(Def, VectorValue, Part);
   } else {
     // Initialize packing with insertelements to start from undef.