[LV] Apply sink-after & interleave-groups as VPlan transformations (NFC)

The sink-after and interleave-group vectorization decisions were so far applied to
VPlan during initial VPlan construction, which complicates VPlan construction – also because of
their inter-dependence. This patch refactors buildVPlanWithRecipes() to construct a simpler
initial VPlan and later apply both these vectorization decisions, in order, as VPlan-to-VPlan
transformations.

Differential Revision: https://reviews.llvm.org/D68577

1 files changed, 20 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index 4b80d1fb20a..bc32e54be72 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -275,18 +275,35 @@ void VPRegionBlock::execute(VPTransformState *State) {
 }
 
 void VPRecipeBase::insertBefore(VPRecipeBase *InsertPos) {
+  assert(!Parent && "Recipe already in some VPBasicBlock");
+  assert(InsertPos->getParent() &&
+         "Insertion position not in any VPBasicBlock");
   Parent = InsertPos->getParent();
   Parent->getRecipeList().insert(InsertPos->getIterator(), this);
 }
 
+void VPRecipeBase::insertAfter(VPRecipeBase *InsertPos) {
+  assert(!Parent && "Recipe already in some VPBasicBlock");
+  assert(InsertPos->getParent() &&
+         "Insertion position not in any VPBasicBlock");
+  Parent = InsertPos->getParent();
+  Parent->getRecipeList().insertAfter(InsertPos->getIterator(), this);
+}
+
+void VPRecipeBase::removeFromParent() {
+  assert(getParent() && "Recipe not in any VPBasicBlock");
+  getParent()->getRecipeList().remove(getIterator());
+  Parent = nullptr;
+}
+
 iplist<VPRecipeBase>::iterator VPRecipeBase::eraseFromParent() {
+  assert(getParent() && "Recipe not in any VPBasicBlock");
   return getParent()->getRecipeList().erase(getIterator());
 }
 
 void VPRecipeBase::moveAfter(VPRecipeBase *InsertPos) {
-  InsertPos->getParent()->getRecipeList().splice(
-      std::next(InsertPos->getIterator()), getParent()->getRecipeList(),
-      getIterator());
+  removeFromParent();
+  insertAfter(InsertPos);
 }
 
 void VPInstruction::generateInstruction(VPTransformState &State,