[VPlanRecipeBase] Add insertBefore helper.

Reviewers: dcaballe, mkuper, hfinkel, hsaito, mssimpso

Reviewed By: dcaballe

Differential Revision: https://reviews.llvm.org/D48080

llvm-svn: 334933
diff --git a/llvm/lib/Transforms/Vectorize/VPlan.cpp b/llvm/lib/Transforms/Vectorize/VPlan.cpp
index 50c71a3..7d07ae0 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -220,6 +220,11 @@
   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;