[llvm] [VPlan] Replace ExtractLast(Elem|LanePerPart) with ExtractLast(Lane/Part) (PR #164124)

[via llvm-commits]

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@@ -37,8 +37,10 @@ define void @test_chained_first_order_recurrences_1(ptr %ptr) {
 ; CHECK-NEXT: Successor(s): middle.block
 ; CHECK-EMPTY:
 ; CHECK-NEXT: middle.block:
-; CHECK-NEXT:    EMIT vp<[[RESUME_1:%.+]]> = extract-last-element ir<%for.1.next>
-; CHECK-NEXT:    EMIT vp<[[RESUME_2:%.+]]>.1 = extract-last-element vp<[[FOR1_SPLICE]]>
+; CHECK-NEXT:    EMIT vp<[[RESUME_1_PART:%.+]]> = extract-last-part ir<%for.1.next>
+; CHECK-NEXT:    EMIT vp<[[RESUME_1:%.+]]> = extract-last-lane vp<[[RESUME_1_PART]]>
+; CHECK-NEXT:    EMIT vp<[[RESUME_2_PART:%.+]]> = extract-last-part vp<[[FOR1_SPLICE]]>
+; CHECK-NEXT:    EMIT vp<[[RESUME_2:%.+]]>.1 = extract-last-lane vp<[[RESUME_2_PART]]>
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ayalz wrote:

An abstract `ExtractFinalLane` could be introduced as shorthand for {extract-last-part + extract-last-lane}, if desired,  perhaps temporarily and/or for gradual change.

https://github.com/llvm/llvm-project/pull/164124