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The generic DAG combiner can now fold atomic fences when needed, so switch 

to using that.

llvm-svn: 106633
This commit is contained in:
Jim Grosbach 2010-06-23 16:25:07 +00:00
parent a8ea498171
commit 6f71039fa4
1 changed files with 6 additions and 57 deletions
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63
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -347,6 +347,12 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
if (!Subtarget->hasSSE2())
setOperationAction(ISD::MEMBARRIER , MVT::Other, Expand);
// On X86 and X86-64, atomic operations are lowered to locked instructions.
// Locked instructions, in turn, have implicit fence semantics (all memory
// operations are flushed before issuing the locked instruction, and they
// are not buffered), so we can fold away the common pattern of
// fence-atomic-fence.
setShouldFoldAtomicFences(true);
// Expand certain atomics
setOperationAction(ISD::ATOMIC_CMP_SWAP, MVT::i8, Custom);
@ -1012,7 +1018,6 @@ X86TargetLowering::X86TargetLowering(X86TargetMachine &TM)
setTargetDAGCombine(ISD::SRL);
setTargetDAGCombine(ISD::OR);
setTargetDAGCombine(ISD::STORE);
setTargetDAGCombine(ISD::MEMBARRIER);
setTargetDAGCombine(ISD::ZERO_EXTEND);
if (Subtarget->is64Bit())
setTargetDAGCombine(ISD::MUL);
@ -9821,61 +9826,6 @@ static SDValue PerformVZEXT_MOVLCombine(SDNode *N, SelectionDAG &DAG) {
return SDValue();
}
// On X86 and X86-64, atomic operations are lowered to locked instructions.
// Locked instructions, in turn, have implicit fence semantics (all memory
// operations are flushed before issuing the locked instruction, and they
// are not buffered), so we can fold away the common pattern of
// fence-atomic-fence.
static SDValue PerformMEMBARRIERCombine(SDNode* N, SelectionDAG &DAG) {
SDValue atomic = N->getOperand(0);
switch (atomic.getOpcode()) {
case ISD::ATOMIC_CMP_SWAP:
case ISD::ATOMIC_SWAP:
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
case ISD::ATOMIC_LOAD_MIN:
case ISD::ATOMIC_LOAD_MAX:
case ISD::ATOMIC_LOAD_UMIN:
case ISD::ATOMIC_LOAD_UMAX:
break;
default:
return SDValue();
}
SDValue fence = atomic.getOperand(0);
if (fence.getOpcode() != ISD::MEMBARRIER)
return SDValue();
switch (atomic.getOpcode()) {
case ISD::ATOMIC_CMP_SWAP:
return SDValue(DAG.UpdateNodeOperands(atomic.getNode(),
fence.getOperand(0),
atomic.getOperand(1), atomic.getOperand(2),
atomic.getOperand(3)), atomic.getResNo());
case ISD::ATOMIC_SWAP:
case ISD::ATOMIC_LOAD_ADD:
case ISD::ATOMIC_LOAD_SUB:
case ISD::ATOMIC_LOAD_AND:
case ISD::ATOMIC_LOAD_OR:
case ISD::ATOMIC_LOAD_XOR:
case ISD::ATOMIC_LOAD_NAND:
case ISD::ATOMIC_LOAD_MIN:
case ISD::ATOMIC_LOAD_MAX:
case ISD::ATOMIC_LOAD_UMIN:
case ISD::ATOMIC_LOAD_UMAX:
return SDValue(DAG.UpdateNodeOperands(atomic.getNode(),
fence.getOperand(0),
atomic.getOperand(1), atomic.getOperand(2)),
atomic.getResNo());
default:
return SDValue();
}
}
static SDValue PerformZExtCombine(SDNode *N, SelectionDAG &DAG) {
// (i32 zext (and (i8 x86isd::setcc_carry), 1)) ->
// (and (i32 x86isd::setcc_carry), 1)
@ -9923,7 +9873,6 @@ SDValue X86TargetLowering::PerformDAGCombine(SDNode *N,
case X86ISD::FAND: return PerformFANDCombine(N, DAG);
case X86ISD::BT: return PerformBTCombine(N, DAG, DCI);
case X86ISD::VZEXT_MOVL: return PerformVZEXT_MOVLCombine(N, DAG);
case ISD::MEMBARRIER: return PerformMEMBARRIERCombine(N, DAG);
case ISD::ZERO_EXTEND: return PerformZExtCombine(N, DAG);
}