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Fix PR7175. Insert copies of a REG_SEQUENCE source if it is used by other REG_SEQUENCE instructions.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103994 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2010-05-17 23:24:12 +00:00
parent 53f7602b61
commit c6dcce3ba5
2 changed files with 50 additions and 1 deletions
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16
lib/CodeGen/TwoAddressInstructionPass.cpp
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@ -134,6 +134,7 @@ namespace {
/// of the de-ssa process. This replaces sources of REG_SEQUENCE as
/// sub-register references of the register defined by REG_SEQUENCE.
bool EliminateRegSequences();
public:
static char ID; // Pass identification, replacement for typeid
TwoAddressInstructionPass() : MachineFunctionPass(&ID) {}
@ -1216,6 +1217,17 @@ TwoAddressInstructionPass::CoalesceExtSubRegs(SmallVector<unsigned,4> &Srcs,
}
}
static bool HasOtherRegSequenceUses(unsigned Reg, MachineInstr *RegSeq,
MachineRegisterInfo *MRI) {
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
UE = MRI->use_end(); UI != UE; ++UI) {
MachineInstr *UseMI = &*UI;
if (UseMI != RegSeq && UseMI->isRegSequence())
return true;
}
return false;
}
/// EliminateRegSequences - Eliminate REG_SEQUENCE instructions as part
/// of the de-ssa process. This replaces sources of REG_SEQUENCE as
/// sub-register references of the register defined by REG_SEQUENCE. e.g.
@ -1261,7 +1273,9 @@ bool TwoAddressInstructionPass::EliminateRegSequences() {
if (DefMI->isExtractSubreg())
RealSrcs.push_back(DefMI->getOperand(1).getReg());
if (!Seen.insert(SrcReg) || MI->getParent() != DefMI->getParent()) {
if (!Seen.insert(SrcReg) ||
MI->getParent() != DefMI->getParent() ||
HasOtherRegSequenceUses(SrcReg, MI, MRI)) {
// REG_SEQUENCE cannot have duplicated operands, add a copy.
// Also add an copy if the source if live-in the block. We don't want
// to end up with a partial-redef of a livein, e.g.