search for: rematerializetrivialdef

...gpr, dead $cpsr = tMOVi8 20, 14, $noreg $r0 = COPY %0:tgpr $r1 = COPY %1:tgpr IIUC, there are a couple of reasons why this happens: (a) tMOVi8 pattern isn't marked with isRematerializable, isAsCheapAsMove, and isMoveImm. (b) After annotating the pattern with above flags, RegisterCoalescer::reMaterializeTrivialDef still bails out because the above assignment has 2 definitions, with only one live definition. To address this issue, I attached a hackish patch that (a) Marks tMOVi8 pattern with: let isReMaterializable = 1, isAsCheapAsAMove = 1, isMoveImm = 1 I am not sure if this is entirely correct ? (b) Modi...

On Tue, 16 Jun 2020 at 15:47, Tim Northover <t.p.northover at gmail.com> wrote: > > On Tue, 16 Jun 2020 at 10:23, Prathamesh Kulkarni via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > (b) Modifies RegisterCoalescer::reMaterializeTrivialDef and > > TargetInstrInfo::isReallyTriviallyReMaterializableGeneric to check > > for single live def, instead of single def. > > This seems dodgy to me. The instruction does also change CPSR so for > the transformation to be valid you have to know that register is dead > where...

...llvm::CriticalAntiDepBreaker::ScanInstruction(llvm::MachineInstr*, unsigned int)in libLLVMCodeGen.a(CriticalAntiDepBreaker.cpp.o) llvm::CriticalAntiDepBreaker::PrescanInstruction(llvm::MachineInstr*) in libLLVMCodeGen.a(CriticalAntiDepBreaker.cpp.o) llvm::SimpleRegisterCoalescing::ReMaterializeTrivialDef(llvm::LiveInterval&, unsigned int, unsigned int, llvm::MachineInstr*)in libLLVMCodeGen.a(SimpleRegisterCoalescing.cpp.o) llvm::SimpleRegisterCoalescing::ReMaterializeTrivialDef(llvm::LiveInterval&, unsigned int, unsigned int, llvm::MachineInstr*)in libLLVMCodeGen.a(SimpleRegisterCoalescing...