Revert "[SCEV] Cache results of computeExitLimit"

This reverts commit r309080.  The patch needs to clear out the
ScalarEvolution::ExitLimits cache in forgetMemoizedResults.

I've replied on the commit thread for the patch with more details.

llvm-svn: 309357

1 files changed, 0 insertions, 21 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index b7421aa3c0d..4d7b59c4763 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6257,14 +6257,6 @@ void ScalarEvolution::forgetLoop(const Loop *L) {
     PushDefUseChildren(I, Worklist);
   }
 
-  for (auto I = ExitLimits.begin(); I != ExitLimits.end();) {
-    auto &Query = I->first;
-    if (Query.L == L)
-      ExitLimits.erase(I++);
-    else
-      ++I;
-  }
-
   // Forget all contained loops too, to avoid dangling entries in the
   // ValuesAtScopes map.
   for (Loop *I : *L)
@@ -6527,18 +6519,6 @@ ScalarEvolution::computeBackedgeTakenCount(const Loop *L,
 ScalarEvolution::ExitLimit
 ScalarEvolution::computeExitLimit(const Loop *L, BasicBlock *ExitingBlock,
                                   bool AllowPredicates) {
-  ExitLimitQuery Query(L, ExitingBlock, AllowPredicates);
-  auto MaybeEL = ExitLimits.find(Query);
-  if (MaybeEL != ExitLimits.end())
-    return MaybeEL->second;
-  ExitLimit EL = computeExitLimitImpl(L, ExitingBlock, AllowPredicates);
-  ExitLimits.insert({Query, EL});
-  return EL;
-}
-
-ScalarEvolution::ExitLimit
-ScalarEvolution::computeExitLimitImpl(const Loop *L, BasicBlock *ExitingBlock,
-                                      bool AllowPredicates) {
 
   // Okay, we've chosen an exiting block.  See what condition causes us to exit
   // at this block and remember the exit block and whether all other targets
@@ -10402,7 +10382,6 @@ ScalarEvolution::ScalarEvolution(ScalarEvolution &&Arg)
       BackedgeTakenCounts(std::move(Arg.BackedgeTakenCounts)),
       PredicatedBackedgeTakenCounts(
           std::move(Arg.PredicatedBackedgeTakenCounts)),
-      ExitLimits(std::move(Arg.ExitLimits)),
       ConstantEvolutionLoopExitValue(
           std::move(Arg.ConstantEvolutionLoopExitValue)),
       ValuesAtScopes(std::move(Arg.ValuesAtScopes)),