[llvm] [LoopVectorizer] Prune VFs based on plan register pressure (PR #132190)

[Sam Tebbs via llvm-commits]

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@@ -7777,6 +7565,18 @@ VectorizationFactor LoopVectorizationPlanner::computeBestVF() {
 
       InstructionCost Cost = cost(*P, VF);
       VectorizationFactor CurrentFactor(VF, Cost, ScalarCost);
+
+      // Make sure that the VF doesn't use more than the number of available
+      // registers
+      const auto &MLU = RU.MaxLocalUsers;
+      if (any_of(MLU, [&](decltype(MLU.front()) &LU) {
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SamTebbs33 wrote:

Done.

https://github.com/llvm/llvm-project/pull/132190