[llvm] [VPlan] Move predication to VPlanTransform (NFC). (PR #128420)

[via llvm-commits]

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@@ -252,6 +208,15 @@ class VPRecipeBuilder {
     }
     return Plan.getOrAddLiveIn(V);
   }
+
+  void updateBlockMaskCache(const DenseMap<VPValue *, VPValue *> &Old2New) {
+    for (auto &[_, V] : BlockMaskCache) {
+      if (auto *New = Old2New.lookup(V)) {
+        V->replaceAllUsesWith(New);
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ayalz wrote:

nit: worth removing V from Old2New now?

https://github.com/llvm/llvm-project/pull/128420