Revert r137655. There is some question about whether the 'landingpad'

instruction should be marked as potentially reading and/or writing memory.

llvm-svn: 137863

llvm/lib/Analysis/LoopInfo.cpp

@@ -99,6 +99,9 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
     return false;
   if (I->mayReadFromMemory())
     return false;
+  // The landingpad instruction is immobile.
+  if (isa<LandingPadInst>(I))
+    return false;
   // Determine the insertion point, unless one was given.
   if (!InsertPt) {
     BasicBlock *Preheader = getLoopPreheader();

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -1418,7 +1418,8 @@ static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) {
   assert(I->hasOneUse() && "Invariants didn't hold!");
 
   // Cannot move control-flow-involving, volatile loads, vaarg, etc.
-  if (isa<PHINode>(I) || I->mayHaveSideEffects() || isa<TerminatorInst>(I))
+  if (isa<PHINode>(I) || isa<LandingPadInst>(I) || I->mayHaveSideEffects() ||
+      isa<TerminatorInst>(I))
     return false;
 
   // Do not sink alloca instructions out of the entry block.

llvm/lib/VMCore/Instruction.cpp

@@ -320,7 +320,6 @@ bool Instruction::mayReadFromMemory() const {
   case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory
   case Instruction::AtomicCmpXchg:
   case Instruction::AtomicRMW:
-  case Instruction::LandingPad:
     return true;
   case Instruction::Call:
     return !cast<CallInst>(this)->doesNotAccessMemory();
@@ -341,7 +340,6 @@ bool Instruction::mayWriteToMemory() const {
   case Instruction::VAArg:
   case Instruction::AtomicCmpXchg:
   case Instruction::AtomicRMW:
-  case Instruction::LandingPad:
     return true;
   case Instruction::Call:
     return !cast<CallInst>(this)->onlyReadsMemory();