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Stop fixing bad machine code in LiveIntervalAnalysis.

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The first def of a virtual register cannot also read the register.
Assert on such bad machine code instead of trying to fix it.
TwoAddressInstructionPass should never create code like that.

llvm-svn: 152010
This commit is contained in:
Jakob Stoklund Olesen 2012-03-04 19:19:10 +00:00
parent 6759dd078a
commit 59bc8c437a
1 changed files with 3 additions and 15 deletions
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18
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -187,21 +187,9 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock *mbb,
// Get the Idx of the defining instructions.
SlotIndex defIndex = MIIdx.getRegSlot(MO.isEarlyClobber());
// Make sure the first definition is not a partial redefinition. Add an
// <imp-def> of the full register.
// FIXME: LiveIntervals shouldn't modify the code like this. Whoever
// created the machine instruction should annotate it with <undef> flags
// as needed. Then we can simply assert here. The REG_SEQUENCE lowering
// is the main suspect.
if (MO.getSubReg()) {
mi->addRegisterDefined(interval.reg);
// Mark all defs of interval.reg on this instruction as reading <undef>.
for (unsigned i = MOIdx, e = mi->getNumOperands(); i != e; ++i) {
MachineOperand &MO2 = mi->getOperand(i);
if (MO2.isReg() && MO2.getReg() == interval.reg && MO2.getSubReg())
MO2.setIsUndef();
}
}
// Make sure the first definition is not a partial redefinition.
assert(!MO.readsReg() && "First def cannot also read virtual register "
"missing <undef> flag?");
VNInfo *ValNo = interval.getNextValue(defIndex, VNInfoAllocator);
assert(ValNo->id == 0 && "First value in interval is not 0?");