[PATCH] D66484: [Attributor][NFCI] Avoid lookups when resolving returned values

[Johannes Doerfert via Phabricator via llvm-commits]

jdoerfert updated this revision to Diff 216473.
jdoerfert added a comment.

Use the call site as a key for the cache


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D66484/new/

https://reviews.llvm.org/D66484

Files:
  llvm/lib/Transforms/IPO/Attributor.cpp


Index: llvm/lib/Transforms/IPO/Attributor.cpp
===================================================================
--- llvm/lib/Transforms/IPO/Attributor.cpp
+++ llvm/lib/Transforms/IPO/Attributor.cpp
@@ -683,13 +683,18 @@
   /// return instructions that might return them.
   DenseMap<Value *, SmallPtrSet<ReturnInst *, 2>> ReturnedValues;
 
+  /// Mapping to remember the number of returned values for a call site such
+  /// that we can avoid updates if nothing changed.
+  DenseMap<const CallBase *, unsigned> NumReturnedValuesPerKnownAA;
+
+  /// Set of unresolved calls returned by the associated function.
   SmallPtrSet<CallBase *, 8> UnresolvedCalls;
 
   /// State flags
   ///
   ///{
-  bool IsFixed;
-  bool IsValidState;
+  bool IsFixed = false;
+  bool IsValidState = true;
   ///}
 
 public:
@@ -775,7 +780,6 @@
   /// See AbstractState::indicateOptimisticFixpoint(...).
   ChangeStatus indicateOptimisticFixpoint() override {
     IsFixed = true;
-    IsValidState &= true;
     return ChangeStatus::UNCHANGED;
   }
 
@@ -1000,6 +1004,15 @@
     if (Unresolved)
       continue;
 
+    // Now track transitively returned values.
+    unsigned &NumRetAA = NumReturnedValuesPerKnownAA[CB];
+    if (NumRetAA == RetValAA.getNumReturnValues()) {
+      LLVM_DEBUG(dbgs() << "[AAReturnedValues] Skip call as it has not "
+                           "changed since it was seen last\n");
+      continue;
+    }
+    NumRetAA = RetValAA.getNumReturnValues();
+
     for (auto &RetValAAIt : RetValAA.returned_values()) {
       Value *RetVal = RetValAAIt.first;
       if (Argument *Arg = dyn_cast<Argument>(RetVal)) {


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