[PATCH] D73716: [SCEV] SCEVExpander::isHighCostExpansionHelper(): begin cost modelling - model cast cost

[Max Kazantsev via Phabricator via llvm-commits]

mkazantsev added inline comments.


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Comment at: llvm/include/llvm/Analysis/ScalarEvolutionExpander.h:176
 
-    /// Return true for expressions that may incur non-trivial cost to evaluate
-    /// at runtime.
+    /// Return true for expressions that can't be evaluate at runtime
+    /// within given \b Budged.
----------------
evaluate -> evaluated?


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Comment at: llvm/include/llvm/Analysis/ScalarEvolutionExpander.h:190
+        return true;
+      return BudgetRemaining < 0;
     }
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You already check this inside the helper, why do it twice?


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Comment at: llvm/lib/Analysis/ScalarEvolutionExpander.cpp:2164
+  if (auto *CastExpr = dyn_cast<SCEVCastExpr>(S)) {
+    unsigned Opcode;
+    switch (S->getSCEVType()) {
----------------
Does it really need to be opcode, or we can pass SCEVType to `getOperationCost`?


Repository:
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  https://reviews.llvm.org/D73716/new/

https://reviews.llvm.org/D73716