[llvm] LV]: consider scalable VF during deciding dead epilogue. (PR #156724)

[David Sherwood via llvm-commits]

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@@ -4425,11 +4430,19 @@ VectorizationFactor LoopVectorizationPlanner::selectEpilogueVectorizationFactor(
 
     // If NextVF is greater than the number of remaining iterations, the
     // epilogue loop would be dead. Skip such factors.
-    if (RemainingIterations && !NextVF.Width.isScalable()) {
-      if (SE.isKnownPredicate(
-              CmpInst::ICMP_UGT,
-              SE.getConstant(TCType, NextVF.Width.getFixedValue()),
-              RemainingIterations))
+    // TODO: We should also consider comparing against scalable RemIter when
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david-arm wrote:

nit: At this point in the code there is no variable called `RemIter` so perhaps better to spell it out in full? i.e. `We should also consider comparing against a scalable RemainingIterations ...`

https://github.com/llvm/llvm-project/pull/156724