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Don't sink insert_subreg, subreg_to_reg, reg_sequence. They are meant to be

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close to their sources to facilitate coalescing.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114631 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2010-09-23 06:53:00 +00:00
parent 266a99d161
commit b0cdf8a446
1 changed files with 10 additions and 1 deletions
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11
lib/CodeGen/MachineSink.cpp
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@ -281,7 +281,7 @@ bool MachineSinking::isWorthBreakingCriticalEdge(MachineInstr *MI,
if (!CEBCandidates.insert(std::make_pair(From, To)))
return true;
if (!(MI->isCopyLike() || MI->getDesc().isAsCheapAsAMove()))
if (!MI->isCopy() && !MI->getDesc().isAsCheapAsAMove())
return true;
// MI is cheap, we probably don't want to break the critical edge for it.
@ -368,9 +368,18 @@ MachineBasicBlock *MachineSinking::SplitCriticalEdge(MachineInstr *MI,
return FromBB->SplitCriticalEdge(ToBB, this);
}
static bool AvoidsSinking(MachineInstr *MI, MachineRegisterInfo *MRI) {
return MI->isInsertSubreg() || MI->isSubregToReg() || MI->isRegSequence();
}
/// SinkInstruction - Determine whether it is safe to sink the specified machine
/// instruction out of its current block into a successor.
bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
// Don't sink insert_subreg, subreg_to_reg, reg_sequence. These are meant to
// be close to the source to make it easier to coalesce.
if (AvoidsSinking(MI, MRI))
return false;
// Check if it's safe to move the instruction.
if (!MI->isSafeToMove(TII, AA, SawStore))
return false;