[llvm] r272236 - Factor out a loopHasNoAbnormalExits; NFC

[Sanjoy Das via llvm-commits]

Author: sanjoy
Date: Wed Jun  8 20:13:54 2016
New Revision: 272236

URL: http://llvm.org/viewvc/llvm-project?rev=272236&view=rev
Log:
Factor out a loopHasNoAbnormalExits; NFC

Modified:
    llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
    llvm/trunk/lib/Analysis/ScalarEvolution.cpp

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=272236&r1=272235&r2=272236&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Wed Jun  8 20:13:54 2016
@@ -781,13 +781,15 @@ namespace llvm {
              SmallVector<PointerIntPair<const Loop *, 2, LoopDisposition>, 2>>
         LoopDispositions;
 
-    /// A cache of the predicate "does the given loop contain an instruction
-    /// that can abnormally exit the loop (i.e. via throwing an exception, by
-    /// terminating the thread cleanly or by infinite looping in a called
-    /// function)?"  The last one is strictly not leaving the loop, but is
-    /// identical to leaving the loop from the viewpoint of reasoning about
-    /// undefined behavior.
-    DenseMap<const Loop *, bool> LoopHasAbnormalExit;
+    /// Cache for \c loopHasNoAbnormalExits.
+    DenseMap<const Loop *, bool> LoopHasNoAbnormalExits;
+
+    /// Returns true if \p L contains no instruction that can abnormally exit
+    /// the loop (i.e. via throwing an exception, by terminating the thread
+    /// cleanly or by infinite looping in a called function).  Strictly
+    /// speaking, the last one is not leaving the loop, but is identical to
+    /// leaving the loop for reasoning about undefined behavior.
+    bool loopHasNoAbnormalExits(const Loop *L);
 
     /// Compute a LoopDisposition value.
     LoopDisposition computeLoopDisposition(const SCEV *S, const Loop *L);

Modified: llvm/trunk/lib/Analysis/ScalarEvolution.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ScalarEvolution.cpp?rev=272236&r1=272235&r2=272236&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ScalarEvolution.cpp (original)
+++ llvm/trunk/lib/Analysis/ScalarEvolution.cpp Wed Jun  8 20:13:54 2016
@@ -4906,13 +4906,12 @@ bool ScalarEvolution::isAddRecNeverPoiso
     }
   }
 
-  if (!LatchControlDependentOnPoison)
-    return false;
-
-  // Now check if loop has abonormal exits (or not), and cache the information.
+  return LatchControlDependentOnPoison && loopHasNoAbnormalExits(L);
+}
 
-  auto Itr = LoopHasAbnormalExit.find(L);
-  if (Itr == LoopHasAbnormalExit.end()) {
+bool ScalarEvolution::loopHasNoAbnormalExits(const Loop *L) {
+  auto Itr = LoopHasNoAbnormalExits.find(L);
+  if (Itr == LoopHasNoAbnormalExits.end()) {
     bool HasAbnormalExit = false;
     for (auto *BB : L->getBlocks()) {
       HasAbnormalExit = any_of(*BB, [](Instruction &I) {
@@ -4921,12 +4920,12 @@ bool ScalarEvolution::isAddRecNeverPoiso
       if (HasAbnormalExit)
         break;
     }
-    auto InsertPair = LoopHasAbnormalExit.insert({L, HasAbnormalExit});
+    auto InsertPair = LoopHasNoAbnormalExits.insert({L, !HasAbnormalExit});
     assert(InsertPair.second && "We just checked!");
     Itr = InsertPair.first;
   }
 
-  return !Itr->second;
+  return Itr->second;
 }
 
 const SCEV *ScalarEvolution::createSCEV(Value *V) {
@@ -5490,7 +5489,7 @@ void ScalarEvolution::forgetLoop(const L
   for (Loop::iterator I = L->begin(), E = L->end(); I != E; ++I)
     forgetLoop(*I);
 
-  LoopHasAbnormalExit.erase(L);
+  LoopHasNoAbnormalExits.erase(L);
 }
 
 void ScalarEvolution::forgetValue(Value *V) {