[PATCH] D130694: [SCEV] Avoid repeated proveNoSignedWrapViaInduction calls.

[Florian Hahn 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 rG214e2d8fe572: [SCEV] Avoid repeated proveNoSignedWrapViaInduction calls. (authored by fhahn).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130694/new/

https://reviews.llvm.org/D130694

Files:
  llvm/include/llvm/Analysis/ScalarEvolution.h
  llvm/lib/Analysis/ScalarEvolution.cpp


Index: llvm/lib/Analysis/ScalarEvolution.cpp
===================================================================
--- llvm/lib/Analysis/ScalarEvolution.cpp
+++ llvm/lib/Analysis/ScalarEvolution.cpp
@@ -4958,6 +4958,10 @@
   if (!AR->isAffine())
     return Result;
 
+  // This function can be expensive, only try to prove NSW once per AddRec.
+  if (!SignedWrapViaInductionTried.insert(AR).second)
+    return Result;
+
   const SCEV *Step = AR->getStepRecurrence(*this);
   const Loop *L = AR->getLoop();
 
@@ -13584,8 +13588,10 @@
   HasRecMap.erase(S);
   MinTrailingZerosCache.erase(S);
 
-  if (auto *AR = dyn_cast<SCEVAddRecExpr>(S))
+  if (auto *AR = dyn_cast<SCEVAddRecExpr>(S)) {
     UnsignedWrapViaInductionTried.erase(AR);
+    SignedWrapViaInductionTried.erase(AR);
+  }
 
   auto ExprIt = ExprValueMap.find(S);
   if (ExprIt != ExprValueMap.end()) {
Index: llvm/include/llvm/Analysis/ScalarEvolution.h
===================================================================
--- llvm/include/llvm/Analysis/ScalarEvolution.h
+++ llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -2119,6 +2119,10 @@
   /// tried.
   SmallPtrSet<const SCEVAddRecExpr *, 16> UnsignedWrapViaInductionTried;
 
+  /// Set of AddRecs for which proving NSW via an induction has already been
+  /// tried.
+  SmallPtrSet<const SCEVAddRecExpr *, 16> SignedWrapViaInductionTried;
+
   /// The head of a linked list of all SCEVUnknown values that have been
   /// allocated. This is used by releaseMemory to locate them all and call
   /// their destructors.


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