commit adf37517304a3a661a033c785cb6b502539db486
author Sanjoy Das <sanjoy@playingwithpointers.com> Mon Dec 04 19:22:01 2017 +0000
committer Sanjoy Das <sanjoy@playingwithpointers.com> Mon Dec 04 19:22:01 2017 +0000
tree 76e0ae4005036aee1cd31110b78b7c8ec814215a
parent 7e36337935ab4d64f947bae93ec0ca0b51d714b1

[SCEV] Use a "Discovered" set instead of a "Visited" set; NFC

Suggested by Max Kazantsev in https://reviews.llvm.org/D39361

llvm-svn: 319679

llvm/lib/Analysis/ScalarEvolution.cpp

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 98c2845..8e60ca0 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6414,11 +6414,9 @@
     SmallVector<Instruction *, 16> Worklist;
     PushLoopPHIs(L, Worklist);
 
-    SmallPtrSet<Instruction *, 8> Visited;
+    SmallPtrSet<Instruction *, 8> Discovered;
     while (!Worklist.empty()) {
       Instruction *I = Worklist.pop_back_val();
-      if (!Visited.insert(I).second)
-        continue;
 
       ValueExprMapType::iterator It =
         ValueExprMap.find_as(static_cast<Value *>(I));
@@ -6460,7 +6458,8 @@
       for (auto *U : I->users())
         if (auto *I = dyn_cast<Instruction>(U)) {
           auto *LoopForUser = LI.getLoopFor(I->getParent());
-          if (LoopForUser && L->contains(LoopForUser))
+          if (LoopForUser && L->contains(LoopForUser) &&
+              Discovered.insert(I).second)
             Worklist.push_back(I);
         }
     }