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

[via llvm-commits]

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@@ -238,7 +242,9 @@ define i64 @find_last_iv(ptr %a, i64 %n, i64 %start) {
 ; CHECK-NEXT: Successor(s): middle.block
 ; CHECK-EMPTY:
 ; CHECK-NEXT: middle.block:
-; CHECK-NEXT:   EMIT vp<[[RDX_RES:%.+]]> = compute-find-iv-result ir<%rdx>, ir<%start>, ir<-9223372036854775808>, ir<%cond>
+; CHECK-NEXT:   EMIT vp<[[RDX_RES_PART:%.+]]> = compute-find-iv-result ir<%rdx>, ir<%start>, ir<-9223372036854775808>, ir<%cond>
+; CHECK-NEXT:   EMIT vp<[[RDX_RES_PART2:%.+]]> = extract-last-part vp<[[RDX_RES_PART]]>
+; CHECK-NEXT:   EMIT vp<[[RDX_RES:%.+]]> = extract-last-lane vp<[[RDX_RES_PART2]]>
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ayalz wrote:

Same expansion as in compute-reduction-result.

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