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Differential D156265

RegisterCoalescer: Remove dubious dropping of implicit virtual register defs
ClosedPublic

Authored by arsenm on Jul 25 2023, 2:44 PM.

Details

Reviewers
qcolombet
kparzysz
lhames
bogner
Summary

Don't understand why this would either be OK or necessary, but doesn't
appear to happen in any tests. This was introduced way back in
76e66c31a0481e72d1ff86c56028d850b6c33cff

Diff Detail

Unit TestsFailed

TimeTest
4,330 msx64 debian > AddressSanitizer-x86_64-linux.TestCases/Linux::auto_memory_profile_test.cpp
510 msx64 debian > LLVM.CodeGen/AMDGPU::coalescer-remat-dead-use.mir
230 msx64 windows > LLVM.CodeGen/AMDGPU::coalescer-remat-dead-use.mir

Revision Contents

Diff 544108

llvm/lib/CodeGen/RegisterCoalescer.cpp

Show First 20 Lines • Show All 1,390 Lines • ▼ Show 20 Linesbool RegisterCoalescer::reMaterializeTrivialDef(const CoalescerPair &CP,
ImplicitOps.reserve(CopyMI->getNumOperands() - ImplicitOps.reserve(CopyMI->getNumOperands() -
CopyMI->getDesc().getNumOperands()); CopyMI->getDesc().getNumOperands());
for (unsigned I = CopyMI->getDesc().getNumOperands(), for (unsigned I = CopyMI->getDesc().getNumOperands(),
E = CopyMI->getNumOperands(); E = CopyMI->getNumOperands();
I != E; ++I) { I != E; ++I) {
MachineOperand &MO = CopyMI->getOperand(I); MachineOperand &MO = CopyMI->getOperand(I);
if (MO.isReg()) { if (MO.isReg()) {
assert(MO.isImplicit() && "No explicit operands after implicit operands."); assert(MO.isImplicit() && "No explicit operands after implicit operands.");
// Discard VReg implicit defs. assert(MO.getReg().isPhysical() && "unexpected implicit virtual register def");
if (MO.getReg().isPhysical())
ImplicitOps.push_back(MO); ImplicitOps.push_back(MO);
} }
} }
CopyMI->eraseFromParent(); CopyMI->eraseFromParent();
ErasedInstrs.insert(CopyMI); ErasedInstrs.insert(CopyMI);
// NewMI may have dead implicit defs (E.g. EFLAGS for MOV<bits>r0 on X86). // NewMI may have dead implicit defs (E.g. EFLAGS for MOV<bits>r0 on X86).
// We need to remember these so we can add intervals once we insert // We need to remember these so we can add intervals once we insert
▲ Show 20 Lines • Show All 2,811 Lines • Show Last 20 Lines