[llvm] [LoopVectorize] Further improve cost model for early exit loops (PR #126235)

[Florian Hahn via llvm-commits]

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@@ -10564,12 +10591,17 @@ bool LoopVectorizePass::processLoop(Loop *L) {
     if (VF.Width.isVector() || SelectedIC > 1)
       Checks.create(L, *LVL.getLAI(), PSE.getPredicate(), VF.Width, SelectedIC);
 
+    InstructionCost EarlyExitCost = InstructionCost::getInvalid();
+    if (VF.Width.isVector() && LVL.hasUncountableEarlyExit())
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fhahn wrote:

Do we need to check if VF is a vector? At the moment, we won't generate interleaved VPlans with early exits, but even when we do, it should probably calculate the correct cost after the VPlan has been unrolled explicitly?

https://github.com/llvm/llvm-project/pull/126235