[llvm] [LV, VPlan] Check if plan is compatible to EVL transform (PR #92092)

[Shih-Po Hung via llvm-commits]

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@@ -1306,7 +1306,16 @@ void VPlanTransforms::addActiveLaneMask(
 /// %NextEVLIV = add IVSize (cast i32 %VPEVVL to IVSize), %EVLPhi
 /// ...
 ///
-void VPlanTransforms::addExplicitVectorLength(VPlan &Plan) {
+bool VPlanTransforms::addExplicitVectorLength(VPlan &Plan) {
+  // EVL transform doesn't support backends where EVL diffs from RuntimeVF
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arcbbb wrote:

Fixed. Thanks!

https://github.com/llvm/llvm-project/pull/92092