[PATCH] D130648: [SCEV] Avoid repeated proveNoUnsignedWrapViaInduction 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 rG8daa338297d5: [SCEV] Avoid repeated proveNoUnsignedWrapViaInduction calls. (authored by fhahn).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D130648/new/

https://reviews.llvm.org/D130648

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
@@ -5007,6 +5007,10 @@
   if (!AR->isAffine())
     return Result;
 
+  // This function can be expensive, only try to prove NUW once per AddRec.
+  if (!UnsignedWrapViaInductionTried.insert(AR).second)
+    return Result;
+
   const SCEV *Step = AR->getStepRecurrence(*this);
   unsigned BitWidth = getTypeSizeInBits(AR->getType());
   const Loop *L = AR->getLoop();
@@ -13580,6 +13584,9 @@
   HasRecMap.erase(S);
   MinTrailingZerosCache.erase(S);
 
+  if (auto *AR = dyn_cast<SCEVAddRecExpr>(S))
+    UnsignedWrapViaInductionTried.erase(AR);
+
   auto ExprIt = ExprValueMap.find(S);
   if (ExprIt != ExprValueMap.end()) {
     for (Value *V : ExprIt->second) {
Index: llvm/include/llvm/Analysis/ScalarEvolution.h
===================================================================
--- llvm/include/llvm/Analysis/ScalarEvolution.h
+++ llvm/include/llvm/Analysis/ScalarEvolution.h
@@ -2115,6 +2115,10 @@
            std::pair<const SCEV *, SmallVector<const SCEVPredicate *, 3>>>
       PredicatedSCEVRewrites;
 
+  /// Set of AddRecs for which proving NUW via an induction has already been
+  /// tried.
+  SmallPtrSet<const SCEVAddRecExpr *, 16> UnsignedWrapViaInductionTried;
+
   /// 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.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D130648.448272.patch
Type: text/x-patch
Size: 1555 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20220728/39483327/attachment.bin>