[llvm] f8623b0 - [SCEV][NFC] Win some compile time from mass forgetMemoizedResults

[Max Kazantsev via llvm-commits]

Author: Max Kazantsev
Date: 2021-10-25T14:09:41+07:00
New Revision: f8623b078305953c7be85fb385713b6851068940

URL: https://github.com/llvm/llvm-project/commit/f8623b078305953c7be85fb385713b6851068940
DIFF: https://github.com/llvm/llvm-project/commit/f8623b078305953c7be85fb385713b6851068940.diff

LOG: [SCEV][NFC] Win some compile time from mass forgetMemoizedResults

Mass forgetMemoizedResults can be done more efficiently than bunch
of individual invocations of helper because we can traverse maps being
updated just once, rather than doing this for each invidivual SCEV.

Should be NFC and supposedly improves compile time.

Differential Revision: https://reviews.llvm.org/D112294
Reviewed By: reames

Added: 
    

Modified: 
    llvm/lib/Analysis/ScalarEvolution.cpp

Removed: 
    


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diff  --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index e7a9808e608d..f0e3237be0a0 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -12757,42 +12757,43 @@ bool ScalarEvolution::hasOperand(const SCEV *S, const SCEV *Op) const {
 void ScalarEvolution::forgetMemoizedResults(ArrayRef<const SCEV *> SCEVs) {
   for (auto *S : SCEVs)
     forgetMemoizedResultsImpl(S);
-}
-
-void ScalarEvolution::forgetMemoizedResultsImpl(const SCEV *S) {
-  ValuesAtScopes.erase(S);
-  LoopDispositions.erase(S);
-  BlockDispositions.erase(S);
-  UnsignedRanges.erase(S);
-  SignedRanges.erase(S);
-  ExprValueMap.erase(S);
-  HasRecMap.erase(S);
-  MinTrailingZerosCache.erase(S);
-
+  SmallPtrSet<const SCEV *, 8> ToForget(SCEVs.begin(), SCEVs.end());
   for (auto I = PredicatedSCEVRewrites.begin();
        I != PredicatedSCEVRewrites.end();) {
     std::pair<const SCEV *, const Loop *> Entry = I->first;
-    if (Entry.first == S)
+    if (ToForget.count(Entry.first))
       PredicatedSCEVRewrites.erase(I++);
     else
       ++I;
   }
 
-  auto RemoveSCEVFromBackedgeMap =
-      [S](DenseMap<const Loop *, BackedgeTakenInfo> &Map) {
+  auto RemoveSCEVFromBackedgeMap = [this, &ToForget](
+      DenseMap<const Loop *, BackedgeTakenInfo> &Map) {
         for (auto I = Map.begin(), E = Map.end(); I != E;) {
           BackedgeTakenInfo &BEInfo = I->second;
-          if (BEInfo.hasOperand(S))
+          if (any_of(ToForget,
+                     [&BEInfo](const SCEV *S) { return BEInfo.hasOperand(S); }))
             Map.erase(I++);
           else
             ++I;
         }
-      };
+  };
 
   RemoveSCEVFromBackedgeMap(BackedgeTakenCounts);
   RemoveSCEVFromBackedgeMap(PredicatedBackedgeTakenCounts);
 }
 
+void ScalarEvolution::forgetMemoizedResultsImpl(const SCEV *S) {
+  ValuesAtScopes.erase(S);
+  LoopDispositions.erase(S);
+  BlockDispositions.erase(S);
+  UnsignedRanges.erase(S);
+  SignedRanges.erase(S);
+  ExprValueMap.erase(S);
+  HasRecMap.erase(S);
+  MinTrailingZerosCache.erase(S);
+}
+
 void
 ScalarEvolution::getUsedLoops(const SCEV *S,
                               SmallPtrSetImpl<const Loop *> &LoopsUsed) {