diff options
Diffstat (limited to 'llvm/lib/Target/ARM/Thumb1InstrInfo.cpp')
| -rw-r--r-- | llvm/lib/Target/ARM/Thumb1InstrInfo.cpp | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/llvm/lib/Target/ARM/Thumb1InstrInfo.cpp b/llvm/lib/Target/ARM/Thumb1InstrInfo.cpp index f1d6fa68d3a..27bff4d75ac 100644 --- a/llvm/lib/Target/ARM/Thumb1InstrInfo.cpp +++ b/llvm/lib/Target/ARM/Thumb1InstrInfo.cpp @@ -54,11 +54,17 @@ void Thumb1InstrInfo::copyPhysReg(MachineBasicBlock &MBB, .addReg(SrcReg, getKillRegState(KillSrc)) .add(predOps(ARMCC::AL)); else { - // FIXME: The performance consequences of this are going to be atrocious. - // Some things to try that should be better: - // * 'mov hi, $src; mov $dst, hi', with hi as either r10 or r11 - // * 'movs $dst, $src' if cpsr isn't live - // See: http://lists.llvm.org/pipermail/llvm-dev/2014-August/075998.html + // FIXME: Can also use 'mov hi, $src; mov $dst, hi', + // with hi as either r10 or r11. + + const TargetRegisterInfo *RegInfo = st.getRegisterInfo(); + if (MBB.computeRegisterLiveness(RegInfo, ARM::CPSR, I) + == MachineBasicBlock::LQR_Dead) { + BuildMI(MBB, I, DL, get(ARM::tMOVSr), DestReg) + .addReg(SrcReg, getKillRegState(KillSrc)) + ->addRegisterDead(ARM::CPSR, RegInfo); + return; + } // 'MOV lo, lo' is unpredictable on < v6, so use the stack to do it BuildMI(MBB, I, DL, get(ARM::tPUSH)) |
