[llvm] [VPlan] Compute induction end values in VPlan. (PR #112145)

[Florian Hahn via llvm-commits]

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@@ -10206,6 +10187,57 @@ LoopVectorizePass::LoopVectorizePass(LoopVectorizeOptions Opts)
       VectorizeOnlyWhenForced(Opts.VectorizeOnlyWhenForced ||
                               !EnableLoopVectorization) {}
 
+/// Prepare \p MainPlan for vectorizing the main vector loop during epilogue
+/// vectorization. Remove ResumePhis from \p MainPlan for inductions that
+/// don't have a corresponding wide induction in \p EpiPlan.
+static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
+  // Collect PHI nodes of widened phis in the VPlan for the epilogue. Those
+  // will need their resume-values computed in the main vector loop. Others
+  // can be removed from the main VPlan.
+  SmallPtrSet<PHINode *, 2> EpiWidenedPhis;
+  for (VPRecipeBase &R :
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fhahn wrote:

Left the concrete tpye for now, as the type isn't directly 'obvious' like via dyn_cast/cast,etc

https://github.com/llvm/llvm-project/pull/112145