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

[Florian Hahn via llvm-commits]

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@@ -12,56 +12,10 @@ define void @replicate_udiv_with_only_first_lane_used(i32 %x, ptr %dst, i64 %d)
 ; CHECK-NEXT:    [[C:%.*]] = icmp eq i32 [[X]], 10
 ; CHECK-NEXT:    br i1 false, label %[[SCALAR_PH:.*]], label %[[VECTOR_PH:.*]]
 ; CHECK:       [[VECTOR_PH]]:
+; CHECK-NEXT:    [[TMP11:%.*]] = getelementptr i16, ptr [[DST]], i64 0
 ; CHECK-NEXT:    br label %[[VECTOR_BODY:.*]]
 ; CHECK:       [[VECTOR_BODY]]:
-; CHECK-NEXT:    [[INDEX:%.*]] = phi i64 [ 0, %[[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], %[[PRED_UDIV_CONTINUE14:.*]] ]
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fhahn wrote:

We should probably add a variant of the test where it cannot be constant folded, to preserve the original test coverage.

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