[llvm] [VPlan] Introduce scalar loop header in plan, remove VPLiveOut. (PR #109975)

[via llvm-commits]

================
@@ -675,48 +675,6 @@ class VPBlockBase {
   virtual VPBlockBase *clone() = 0;
 };
 
-/// A value that is used outside the VPlan. The operand of the user needs to be
-/// added to the associated phi node. The incoming block from VPlan is
-/// determined by where the VPValue is defined: if it is defined by a recipe
-/// outside a region, its parent block is used, otherwise the middle block is
-/// used.
-class VPLiveOut : public VPUser {
----------------
ayalz wrote:

Dropping seems cleaner to me.

https://github.com/llvm/llvm-project/pull/109975