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ScheduleDAG: record PhysReg dependencies represented by CopyFromReg nodes

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x86's CMPXCHG -> EFLAGS consumer wasn't being recorded as a real EFLAGS
dependency because it was represented by a pair of CopyFromReg(EFLAGS) ->
CopyToReg(EFLAGS) nodes. ScheduleDAG was expecting the source to be an
implicit-def on the instruction, where the result numbers in the DAG and the
Uses list in TableGen matched up precisely.

The Copy notation seems much more robust, so this patch extends ScheduleDAG
rather than refactoring x86.

Should fix PR20376.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220529 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tim Northover
2014-10-23 22:31:48 +00:00
parent 991327143f
commit c0ecebb32b
4 changed files with 122 additions and 19 deletions
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15
lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
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@ -119,15 +119,20 @@ static void CheckForPhysRegDependency(SDNode *Def, SDNode *User, unsigned Op,
return;
unsigned ResNo = User->getOperand(2).getResNo();
if (Def->isMachineOpcode()) {
if (Def->getOpcode() == ISD::CopyFromReg &&
cast<RegisterSDNode>(Def->getOperand(1))->getReg() == Reg) {
PhysReg = Reg;
} else if (Def->isMachineOpcode()) {
const MCInstrDesc &II = TII->get(Def->getMachineOpcode());
if (ResNo >= II.getNumDefs() &&
II.ImplicitDefs[ResNo - II.getNumDefs()] == Reg) {
II.ImplicitDefs[ResNo - II.getNumDefs()] == Reg)
PhysReg = Reg;
const TargetRegisterClass *RC =
}
if (PhysReg != 0) {
const TargetRegisterClass *RC =
TRI->getMinimalPhysRegClass(Reg, Def->getValueType(ResNo));
Cost = RC->getCopyCost();
}
Cost = RC->getCopyCost();
}
}