[llvm] [VPlan] Fix first-order splices without header mask not using EVL (PR #146672)

[Luke Lau via llvm-commits]

================
@@ -2114,21 +2114,19 @@ void VPlanTransforms::addActiveLaneMask(
     HeaderMask->replaceAllUsesWith(LaneMask);
 }
 
-/// Try to convert \p CurRecipe to a corresponding EVL-based recipe. Returns
-/// nullptr if no EVL-based recipe could be created.
+/// Try to optimize a \p CurRecipe masked by \p HeaderMask to a corresponding
+/// EVL-based recipe without the mask. Returns nullptr if no EVL-based recipe
----------------
lukel97 wrote:

But the header mask should be removed if successful? Should this sasy `without the header mask` instead?

https://github.com/llvm/llvm-project/pull/146672