[llvm] [VPlan] Introduce VPlanConstantFolder (PR #125365)

[Florian Hahn via llvm-commits]

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@@ -1254,19 +1254,18 @@ define i64 @constant_folded_previous_value() {
 ; UNROLL-NO-VF-NEXT:  entry:
 ; UNROLL-NO-VF-NEXT:    br i1 false, label [[SCALAR_PH:%.*]], label [[VECTOR_PH:%.*]]
 ; UNROLL-NO-VF:       vector.ph:
-; UNROLL-NO-VF-NEXT:    [[TMP0:%.*]] = add i64 0, 1
 ; UNROLL-NO-VF-NEXT:    br label [[VECTOR_BODY:%.*]]
 ; UNROLL-NO-VF:       vector.body:
-; UNROLL-NO-VF-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
-; UNROLL-NO-VF-NEXT:    [[VECTOR_RECUR:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[TMP0]], [[VECTOR_BODY]] ]
-; UNROLL-NO-VF-NEXT:    [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 2
-; UNROLL-NO-VF-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[INDEX_NEXT]], 1000
+; UNROLL-NO-VF-NEXT:    [[VECTOR_RECUR:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[TMP0:%.*]], [[VECTOR_BODY]] ]
+; UNROLL-NO-VF-NEXT:    [[VECTOR_RECUR1:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ 1, [[VECTOR_BODY]] ]
+; UNROLL-NO-VF-NEXT:    [[TMP0]] = add nuw i64 [[VECTOR_RECUR]], 2
+; UNROLL-NO-VF-NEXT:    [[TMP1:%.*]] = icmp eq i64 [[TMP0]], 1000
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fhahn wrote:

can we keep the original names here, what's called `VECTOR_RECUR` is still the `INDEX`?

https://github.com/llvm/llvm-project/pull/125365