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Revert r141569 and r141576.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141594 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel
2011-10-10 23:18:02 +00:00
parent f6c35c59f5
commit db7334dbc5
6 changed files with 62 additions and 88 deletions
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lib/CodeGen/MachineLICM.cpp
-29
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@@ -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.