[VPlan] Add VPRecipeBase::toVPUser helper (NFC).

This adds a helper to convert a VPRecipeBase pointer to a VPUser, for
recipes that inherit from VPUser. Once VPRecipeBase directly inherits
from VPUser this helper can be removed.

Author: fhahn

llvm/lib/Transforms/Vectorize/VPlan.cpp

@@ -77,6 +77,30 @@ void VPRecipeBase::dump() const {
   dbgs() << "\n";
 }
 
+VPUser *VPRecipeBase::toVPUser() {
+  if (auto *U = dyn_cast<VPInstruction>(this))
+    return U;
+  if (auto *U = dyn_cast<VPWidenRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPWidenCallRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPWidenSelectRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPWidenGEPRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPBlendRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPInterleaveRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPReplicateRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPBranchOnMaskRecipe>(this))
+    return U;
+  if (auto *U = dyn_cast<VPWidenMemoryInstructionRecipe>(this))
+    return U;
+  return nullptr;
+}
+
 // Get the top-most entry block of \p Start. This is the entry block of the
 // containing VPlan. This function is templated to support both const and non-const blocks
 template <typename T> static T *getPlanEntry(T *Start) {

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -676,10 +676,15 @@ class VPRecipeBase : public ilist_node_with_parent<VPRecipeBase, VPBasicBlock> {
   ///
   /// \returns an iterator pointing to the element after the erased one
   iplist<VPRecipeBase>::iterator eraseFromParent();
+
+  /// Returns a pointer to a VPUser, if the recipe inherits from VPUser or
+  /// nullptr otherwise.
+  VPUser *toVPUser();
 };
 
 inline bool VPUser::classof(const VPRecipeBase *Recipe) {
-  return Recipe->getVPRecipeID() == VPRecipeBase::VPWidenSC ||
+  return Recipe->getVPRecipeID() == VPRecipeBase::VPInstructionSC ||
+         Recipe->getVPRecipeID() == VPRecipeBase::VPWidenSC ||
          Recipe->getVPRecipeID() == VPRecipeBase::VPWidenCallSC ||
          Recipe->getVPRecipeID() == VPRecipeBase::VPWidenSelectSC ||
          Recipe->getVPRecipeID() == VPRecipeBase::VPWidenGEPSC ||

llvm/unittests/Transforms/Vectorize/VPlanTest.cpp

@@ -339,6 +339,16 @@ compound=true
   }
 }
 
+TEST(VPRecipeTest, CastVPInstructionToVPUser) {
+  VPValue Op1;
+  VPValue Op2;
+  VPInstruction Recipe(Instruction::Add, {&Op1, &Op2});
+  EXPECT_TRUE(isa<VPUser>(&Recipe));
+  VPRecipeBase *BaseR = &Recipe;
+  EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&Recipe, BaseR->toVPUser());
+}
+
 TEST(VPRecipeTest, CastVPWidenRecipeToVPUser) {
   LLVMContext C;
 
@@ -354,6 +364,7 @@ TEST(VPRecipeTest, CastVPWidenRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&WidenR));
   VPRecipeBase *WidenRBase = &WidenR;
   EXPECT_TRUE(isa<VPUser>(WidenRBase));
+  EXPECT_EQ(&WidenR, WidenRBase->toVPUser());
   delete AI;
 }
 
@@ -372,6 +383,7 @@ TEST(VPRecipeTest, CastVPWidenCallRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&Recipe));
   VPRecipeBase *BaseR = &Recipe;
   EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&Recipe, BaseR->toVPUser());
   delete Call;
 }
 
@@ -394,6 +406,7 @@ TEST(VPRecipeTest, CastVPWidenSelectRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&WidenSelectR));
   VPRecipeBase *BaseR = &WidenSelectR;
   EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&WidenSelectR, BaseR->toVPUser());
   delete SelectI;
 }
 
@@ -413,6 +426,7 @@ TEST(VPRecipeTest, CastVPWidenGEPRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&Recipe));
   VPRecipeBase *BaseR = &Recipe;
   EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&Recipe, BaseR->toVPUser());
   delete GEP;
 }
 
@@ -442,6 +456,7 @@ TEST(VPRecipeTest, CastVPInterleaveRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&Recipe));
   VPRecipeBase *BaseR = &Recipe;
   EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&Recipe, BaseR->toVPUser());
 }
 
 TEST(VPRecipeTest, CastVPReplicateRecipeToVPUser) {
@@ -468,6 +483,7 @@ TEST(VPRecipeTest, CastVPBranchOnMaskRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&Recipe));
   VPRecipeBase *BaseR = &Recipe;
   EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&Recipe, BaseR->toVPUser());
 }
 
 TEST(VPRecipeTest, CastVPWidenMemoryInstructionRecipeToVPUser) {
@@ -483,6 +499,7 @@ TEST(VPRecipeTest, CastVPWidenMemoryInstructionRecipeToVPUser) {
   EXPECT_TRUE(isa<VPUser>(&Recipe));
   VPRecipeBase *BaseR = &Recipe;
   EXPECT_TRUE(isa<VPUser>(BaseR));
+  EXPECT_EQ(&Recipe, BaseR->toVPUser());
   delete Load;
 }