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Author: Mel-Chen

llvm/lib/Transforms/Vectorize/VPlan.h

@@ -1275,7 +1275,9 @@ class VPInstruction : public VPRecipeWithIRFlags,
     // for all lanes, depending on its uses).
     PtrAdd,
     // Selects elements from two vectors (second and third operand) based on a
-    // condition vector (first operand) and a pivot index (fourth operand).
+    // condition vector (first operand) and a pivot index (fourth operand). The
+    // lanes whose positions are greater than or equal to the pivot are taken
+    // from the third operand.
     MergeUntilPivot,
   };
 

llvm/lib/Transforms/Vectorize/VPlanPatternMatch.h

@@ -59,7 +59,7 @@ template <typename Class> struct bind_ty {
 struct specificval_ty {
   const VPValue *Val;
 
-  specificval_ty(const VPValue *V) : Val(V) {} //std::move?
+  specificval_ty(const VPValue *V) : Val(V) {}
 
   bool match(VPValue *VPV) { return VPV == Val; }
 };

llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp

@@ -680,7 +680,6 @@ Value *VPInstruction::generate(VPTransformState &State) {
     Value *OnFalse = State.get(getOperand(2), Part);
     Value *Pivot = State.get(getOperand(3), VPIteration(0, 0));
     assert(Pivot->getType()->isIntegerTy() && "Pivot should be an integer.");
-
     return Builder.CreateIntrinsic(Intrinsic::vp_merge, {OnTrue->getType()},
                                    {Cond, OnTrue, OnFalse, Pivot}, nullptr,
                                    Name);