Revert r141569 and r141576.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141594 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 0 insertions, 29 deletions

diff --git a/lib/CodeGen/MachineLICM.cpp b/lib/CodeGen/MachineLICM.cpp
index bd25b2c6b6..d310f252e2 100644
--- a/lib/CodeGen/MachineLICM.cpp
+++ b/lib/CodeGen/MachineLICM.cpp
@@ -168,11 +168,6 @@ namespace {
     /// 
     bool IsLoopInvariantInst(MachineInstr &I);
 
-    /// IsGuaranteedToExecute - check to make sure that the MI dominates
-    /// all of the exit blocks.  If it doesn't, then there is a path out of the
-    /// loop which does not execute this instruction, so we can't hoist it.
-    bool IsGuaranteedToExecute(MachineInstr *MI);
-
     /// HasAnyPHIUse - Return true if the specified register is used by any
     /// phi node.
     bool HasAnyPHIUse(unsigned Reg) const;
@@ -1134,28 +1129,6 @@ bool MachineLICM::EliminateCSE(MachineInstr *MI,
   return false;
 }
 
-/// IsGuaranteedToExecute - check to make sure that the instruction dominates
-/// all of the exit blocks.  If it doesn't, then there is a path out of the loop
-/// which does not execute this instruction, so we can't hoist it.
-bool MachineLICM::IsGuaranteedToExecute(MachineInstr *MI) {
-  // If the instruction is in the header block for the loop (which is very
-  // common), it is always guaranteed to dominate the exit blocks.  Since this
-  // is a common case, and can save some work, check it now.
-  if (MI->getParent() == CurLoop->getHeader())
-    return true;
-
-  // Get the exit blocks for the current loop.
-  SmallVector<MachineBasicBlock*, 8> ExitingBlocks;
-  CurLoop->getExitingBlocks(ExitingBlocks);
-
-  // Verify that the block dominates each of the exit blocks of the loop.
-  for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i)
-    if (!DT->dominates(MI->getParent(), ExitingBlocks[i]))
-      return false;
-
-  return true;
-}
-
 /// Hoist - When an instruction is found to use only loop invariant operands
 /// that are safe to hoist, this instruction is called to do the dirty work.
 ///
@@ -1166,8 +1139,6 @@ bool MachineLICM::Hoist(MachineInstr *MI, MachineBasicBlock *Preheader) {
     MI = ExtractHoistableLoad(MI);
     if (!MI) return false;
   }
-  if (!IsGuaranteedToExecute(MI))
-    return false;
 
   // Now move the instructions to the predecessor, inserting it before any
   // terminator instructions.