[PATCH] D138475: [SCEVExpander] Support cost evaluation of several SCEVs with same budget

[Max Kazantsev via Phabricator via llvm-commits]

This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG6dac170140d0: [SCEVExpander] Support cost evaluation of several SCEVs with same budget (authored by mkazantsev).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D138475/new/

https://reviews.llvm.org/D138475

Files:
  llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
  llvm/lib/Transforms/Utils/SimplifyIndVar.cpp


Index: llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -221,11 +221,8 @@
 
   // Do not generate something ridiculous.
   auto *PHTerm = Preheader->getTerminator();
-  if (Rewriter.isHighCostExpansion(InvariantLHS, L, SCEVCheapExpansionBudget,
-                                   TTI, PHTerm))
-    return false;
-  if (Rewriter.isHighCostExpansion(InvariantRHS, L, SCEVCheapExpansionBudget,
-                                   TTI, PHTerm))
+  if (Rewriter.isHighCostExpansion({ InvariantLHS, InvariantRHS }, L,
+                                   2 * SCEVCheapExpansionBudget, TTI, PHTerm))
     return false;
   auto *NewLHS =
       Rewriter.expandCodeFor(InvariantLHS, IVOperand->getType(), PHTerm);
Index: llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
===================================================================
--- llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
+++ llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
@@ -219,11 +219,11 @@
   /// Return true for expressions that can't be evaluated at runtime
   /// within given \b Budget.
   ///
-  /// At is a parameter which specifies point in code where user is going to
-  /// expand this expression. Sometimes this knowledge can lead to
+  /// \p At is a parameter which specifies point in code where user is going to
+  /// expand these expressions. Sometimes this knowledge can lead to
   /// a less pessimistic cost estimation.
-  bool isHighCostExpansion(const SCEV *Expr, Loop *L, unsigned Budget,
-                           const TargetTransformInfo *TTI,
+  bool isHighCostExpansion(ArrayRef<const SCEV *> Exprs, Loop *L,
+                           unsigned Budget, const TargetTransformInfo *TTI,
                            const Instruction *At) {
     assert(TTI && "This function requires TTI to be provided.");
     assert(At && "This function requires At instruction to be provided.");
@@ -233,7 +233,8 @@
     SmallPtrSet<const SCEV *, 8> Processed;
     InstructionCost Cost = 0;
     unsigned ScaledBudget = Budget * TargetTransformInfo::TCC_Basic;
-    Worklist.emplace_back(-1, -1, Expr);
+    for (auto *Expr : Exprs)
+      Worklist.emplace_back(-1, -1, Expr);
     while (!Worklist.empty()) {
       const SCEVOperand WorkItem = Worklist.pop_back_val();
       if (isHighCostExpansionHelper(WorkItem, L, *At, Cost, ScaledBudget, *TTI,


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