diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/AVR/AVRRegisterInfo.cpp | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/llvm/lib/Target/AVR/AVRRegisterInfo.cpp b/llvm/lib/Target/AVR/AVRRegisterInfo.cpp index 5cc7eaf8add..2813e24d2ac 100644 --- a/llvm/lib/Target/AVR/AVRRegisterInfo.cpp +++ b/llvm/lib/Target/AVR/AVRRegisterInfo.cpp @@ -65,12 +65,18 @@ BitVector AVRRegisterInfo::getReservedRegs(const MachineFunction &MF) const { Reserved.set(AVR::SPH); Reserved.set(AVR::SP); - // Reserve the frame pointer registers r28 and r29 if the function requires one. - if (TFI->hasFP(MF)) { - Reserved.set(AVR::R28); - Reserved.set(AVR::R29); - Reserved.set(AVR::R29R28); - } + // We tenatively reserve the frame pointer register r29:r28 because the + // function may require one, but we cannot tell until register allocation + // is complete, which can be too late. + // + // Instead we just unconditionally reserve the Y register. + // + // TODO: Write a pass to enumerate functions which reserved the Y register + // but didn't end up needing a frame pointer. In these, we can + // convert one or two of the spills inside to use the Y register. + Reserved.set(AVR::R28); + Reserved.set(AVR::R29); + Reserved.set(AVR::R29R28); return Reserved; } |
