[VPlanRecipeBase] Add insertBefore helper.

[dcaballe]

Thanks for the patch! LGTM.
I think it's ok to kept these utilities in the VPRecipeBase class for now. Eventually, if we add too many, we may want to move them to a VPInstructionUtils, same as what we are doing for VPBlockBase.

lib/Transforms/Vectorize/VPlan.h

556

instruction -> recipe?

[fhahn]

Added Cmake changes to add VPlanTest.cpp, so we do not depend on any other patches. Also change instruction->recipe in comment.

lib/Transforms/Vectorize/VPlan.h

public:
   const VPBasicBlock *getParent() const { return Parent; }
 
   /// The method which generates the output IR instructions that correspond to
   /// this VPRecipe, thereby "executing" the VPlan.
   virtual void execute(struct VPTransformState &State) = 0;
 
   /// Each recipe prints itself.
   virtual void print(raw_ostream &O, const Twine &Indent) const = 0;
+
+  /// Insert an unlinked recipe into a basic block immediately before
+  /// the specified recipe.
+  void insertBefore(VPRecipeBase *InsertPos);
 };
 
 /// This is a concrete Recipe that models a single VPlan-level instruction.
 /// While as any Recipe it may generate a sequence of IR instructions when
 /// executed, these instructions would always form a single-def expression as
 /// the VPInstruction is also a single def-use vertex.
 class VPInstruction : public VPUser, public VPRecipeBase {
 public:
public:
 
   inline size_t size() const { return Recipes.size(); }
   inline bool empty() const { return Recipes.empty(); }
   inline const VPRecipeBase &front() const { return Recipes.front(); }
   inline VPRecipeBase &front() { return Recipes.front(); }
   inline const VPRecipeBase &back() const { return Recipes.back(); }
   inline VPRecipeBase &back() { return Recipes.back(); }
 
+  /// Returns a reference to the list of recipes.
+  RecipeListTy &getRecipeList() { return Recipes; }
+
   /// Returns a pointer to a member of the recipe list.
   static RecipeListTy VPBasicBlock::*getSublistAccess(VPRecipeBase *) {
     return &VPBasicBlock::Recipes;
   }
 
   /// Method to support type inquiry through isa, cast, and dyn_cast.
   static inline bool classof(const VPBlockBase *V) {
     return V->getVPBlockID() == VPBlockBase::VPBasicBlockSC;

lib/Transforms/Vectorize/VPlan.cpp

for (unsigned Lane = 0, VF = State->VF; Lane < VF; ++Lane) {
       }
     }
   }
 
   // Exit replicating mode.
   State->Instance.reset();
 }
 
+void VPRecipeBase::insertBefore(VPRecipeBase *InsertPos) {
+  InsertPos->getParent()->getRecipeList().insert(InsertPos->getIterator(),
+                                                 this);
+}
+
 void VPInstruction::generateInstruction(VPTransformState &State,
                                         unsigned Part) {
   IRBuilder<> &Builder = State.Builder;
 
   if (Instruction::isBinaryOp(getOpcode())) {
     Value *A = State.get(getOperand(0), Part);
     Value *B = State.get(getOperand(1), Part);
     Value *V = Builder.CreateBinOp((Instruction::BinaryOps)getOpcode(), A, B);

unittests/Transforms/CMakeLists.txt

 add_subdirectory(IPO)
 add_subdirectory(Scalar)
 add_subdirectory(Utils)
+add_subdirectory(Vectorize)

unittests/Transforms/Vectorize/CMakeLists.txt

+set(LLVM_LINK_COMPONENTS
+  Vectorize
+  )
+
+add_llvm_unittest(VectorizeTests
+  VPlanTest.cpp
+  )

unittests/Transforms/Vectorize/VPlanTest.cpp

+//===- llvm/unittests/Transforms/Vectorize/VPlanTest.cpp - VPlan tests ----===//
+//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "../lib/Transforms/Vectorize/VPlan.h"
+#include "llvm/IR/Instruction.h"
+#include "llvm/IR/Instructions.h"
+#include "gtest/gtest.h"
+
+namespace llvm {
+namespace {
+
+#define CHECK_ITERATOR(Range1, ...)                                            \
+  do {                                                                         \
+    std::vector<VPInstruction *> Tmp = {__VA_ARGS__};                          \
+    EXPECT_EQ((size_t)std::distance(Range1.begin(), Range1.end()),             \
+              Tmp.size());                                                     \
+    for (auto Pair : zip(Range1, make_range(Tmp.begin(), Tmp.end())))          \
+      EXPECT_EQ(&std::get<0>(Pair), std::get<1>(Pair));                        \
+  } while (0)
+
+TEST(VPInstructionTest, insertBefore) {
+  VPInstruction *I1 = new VPInstruction(0, {});
+  VPInstruction *I2 = new VPInstruction(1, {});
+  VPInstruction *I3 = new VPInstruction(2, {});
+
+  VPBasicBlock VPBB1;
+  VPBB1.appendRecipe(I1);
+
+  I2->insertBefore(I1);
+  CHECK_ITERATOR(VPBB1, I2, I1);
+
+  I3->insertBefore(I2);
+  CHECK_ITERATOR(VPBB1, I3, I2, I1);
+}
+
+} // namespace
+} // namespace llvm