[llvm] [VPlan] Update scalar induction resume values in VPlan. (PR #110577)

[via llvm-commits]

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@@ -356,9 +356,10 @@ define void @latch_branch_cost(ptr %dst) {
 ; DEFAULT-NEXT:    br i1 false, label [[SCALAR_PH]], label [[VEC_EPILOG_PH]]
 ; DEFAULT:       vec.epilog.ph:
 ; DEFAULT-NEXT:    [[VEC_EPILOG_RESUME_VAL:%.*]] = phi i64 [ 96, [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_PH]] ]
+; DEFAULT-NEXT:    [[VEC_EPILOG_RESUME_VAL1:%.*]] = phi i64 [ 96, [[VEC_EPILOG_ITER_CHECK]] ], [ 0, [[VECTOR_PH]] ]
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ayalz wrote:

This is an example of a redundant phi, i.e., VEC_EPILOG_RESUME_VAL is now unused?

Worth cleaning up, perhaps VPlan2VPlan?

Perhaps contributes to increase(?) in de-duplications.

https://github.com/llvm/llvm-project/pull/110577