diff options
Diffstat (limited to 'contrib/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp')
| -rw-r--r-- | contrib/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/contrib/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp b/contrib/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp index ba00b3d79da9..a65e22fd86e8 100644 --- a/contrib/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp +++ b/contrib/llvm/lib/Target/ARM/Thumb1FrameLowering.cpp @@ -611,6 +611,12 @@ bool Thumb1FrameLowering::emitPopSpecialFixUp(MachineBasicBlock &MBB, unsigned TemporaryReg = 0; BitVector PopFriendly = TRI.getAllocatableSet(MF, TRI.getRegClass(ARM::tGPRRegClassID)); + // R7 may be used as a frame pointer, hence marked as not generally + // allocatable, however there's no reason to not use it as a temporary for + // restoring LR. + if (STI.useR7AsFramePointer()) + PopFriendly.set(ARM::R7); + assert(PopFriendly.any() && "No allocatable pop-friendly register?!"); // Rebuild the GPRs from the high registers because they are removed // form the GPR reg class for thumb1. @@ -622,17 +628,20 @@ bool Thumb1FrameLowering::emitPopSpecialFixUp(MachineBasicBlock &MBB, GPRsNoLRSP.reset(ARM::PC); findTemporariesForLR(GPRsNoLRSP, PopFriendly, UsedRegs, PopReg, TemporaryReg); - // If we couldn't find a pop-friendly register, restore LR before popping the - // other callee-saved registers, so we can use one of them as a temporary. + // If we couldn't find a pop-friendly register, try restoring LR before + // popping the other callee-saved registers, so we could use one of them as a + // temporary. bool UseLDRSP = false; if (!PopReg && MBBI != MBB.begin()) { auto PrevMBBI = MBBI; PrevMBBI--; if (PrevMBBI->getOpcode() == ARM::tPOP) { - MBBI = PrevMBBI; - UsedRegs.stepBackward(*MBBI); + UsedRegs.stepBackward(*PrevMBBI); findTemporariesForLR(GPRsNoLRSP, PopFriendly, UsedRegs, PopReg, TemporaryReg); - UseLDRSP = true; + if (PopReg) { + MBBI = PrevMBBI; + UseLDRSP = true; + } } } |