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[RegisterCoalescer] Make sure each live-range has only one component, as

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demanded by the machine verifier.
After shrinking a live-range to its uses, it is possible to create several
smaller live-ranges. When this happens, shrinkToUses returns true and we need to
split the different components into their own live-ranges.

The problem does not reproduce on any in-tree target but Jonas Paulsson
<jonas.paulsson@ericsson.com>, who reported the problem, checked that this patch
fixes the issue.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236658 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Quentin Colombet 2015-05-06 22:41:50 +00:00
parent b350776f03
commit d15319f75f
1 changed files with 30 additions and 4 deletions
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34
lib/CodeGen/RegisterCoalescer.cpp
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@ -224,6 +224,32 @@ namespace {
/// Dst, we can drop \p Copy.
bool applyTerminalRule(const MachineInstr &Copy) const;
/// Check whether or not \p LI is composed by multiple connected
/// components and if that is the case, fix that.
void splitNewRanges(LiveInterval *LI) {
ConnectedVNInfoEqClasses ConEQ(*LIS);
unsigned NumComps = ConEQ.Classify(LI);
if (NumComps <= 1)
return;
SmallVector<LiveInterval*, 8> NewComps(1, LI);
for (unsigned i = 1; i != NumComps; ++i) {
unsigned VReg = MRI->createVirtualRegister(MRI->getRegClass(LI->reg));
NewComps.push_back(&LIS->createEmptyInterval(VReg));
}
ConEQ.Distribute(&NewComps[0], *MRI);
}
/// Wrapper method for \see LiveIntervals::shrinkToUses.
/// This method does the proper fixing of the live-ranges when the afore
/// mentioned method returns true.
void shrinkToUses(LiveInterval *LI,
SmallVectorImpl<MachineInstr * > *Dead = nullptr) {
if (LIS->shrinkToUses(LI, Dead))
// We may have created multiple connected components, split them.
splitNewRanges(LI);
}
public:
static char ID; ///< Class identification, replacement for typeinfo
RegisterCoalescer() : MachineFunctionPass(ID) {
@ -556,7 +582,7 @@ bool RegisterCoalescer::adjustCopiesBackFrom(const CoalescerPair &CP,
// will also add the isKill marker.
CopyMI->substituteRegister(IntA.reg, IntB.reg, 0, *TRI);
if (AS->end == CopyIdx)
LIS->shrinkToUses(&IntA);
shrinkToUses(&IntA);
++numExtends;
return true;
@ -1046,7 +1072,7 @@ bool RegisterCoalescer::reMaterializeTrivialDef(const CoalescerPair &CP,
++NumReMats;
// The source interval can become smaller because we removed a use.
LIS->shrinkToUses(&SrcInt, &DeadDefs);
shrinkToUses(&SrcInt, &DeadDefs);
if (!DeadDefs.empty()) {
// If the virtual SrcReg is completely eliminated, update all DBG_VALUEs
// to describe DstReg instead.
@ -1427,7 +1453,7 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
}
if (ShrinkMainRange) {
LiveInterval &LI = LIS->getInterval(CP.getDstReg());
LIS->shrinkToUses(&LI);
shrinkToUses(&LI);
}
// SrcReg is guaranteed to be the register whose live interval that is
@ -2635,7 +2661,7 @@ bool RegisterCoalescer::joinVirtRegs(CoalescerPair &CP) {
LHSVals.eraseInstrs(ErasedInstrs, ShrinkRegs);
RHSVals.eraseInstrs(ErasedInstrs, ShrinkRegs);
while (!ShrinkRegs.empty())
LIS->shrinkToUses(&LIS->getInterval(ShrinkRegs.pop_back_val()));
shrinkToUses(&LIS->getInterval(ShrinkRegs.pop_back_val()));
// Join RHS into LHS.
LHS.join(RHS, LHSVals.getAssignments(), RHSVals.getAssignments(), NewVNInfo);