[llvm] [VPlan] Only use selectVectorizationFactor for cross-check (NFCI). (PR #103033)

[via llvm-commits]

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@@ -6995,11 +6994,11 @@ LoopVectorizationPlanner::plan(ElementCount UserVF, unsigned UserIC) {
       if (!hasPlanWithVF(UserVF)) {
         LLVM_DEBUG(dbgs() << "LV: No VPlan could be built for " << UserVF
                           << ".\n");
-        return std::nullopt;
+        return;
       }
 
       LLVM_DEBUG(printPlans(dbgs()));
-      return {{UserVF, 0, 0}};
+      return;
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ayalz wrote:

nit: suffice to have printPlans() print "LV: No VPlans built.\n" if there are none, and always call it and return.

https://github.com/llvm/llvm-project/pull/103033