diff --git a/lib/Target/ARM/ARMBaseRegisterInfo.cpp b/lib/Target/ARM/ARMBaseRegisterInfo.cpp index b153b68eb9b..7b4086875cc 100644 --- a/lib/Target/ARM/ARMBaseRegisterInfo.cpp +++ b/lib/Target/ARM/ARMBaseRegisterInfo.cpp @@ -667,8 +667,14 @@ bool ARMBaseRegisterInfo::hasBasePointer(const MachineFunction &MF) const { } bool ARMBaseRegisterInfo::canRealignStack(const MachineFunction &MF) const { + const MachineFrameInfo *MFI = MF.getFrameInfo(); const ARMFunctionInfo *AFI = MF.getInfo(); - return (RealignStack && !AFI->isThumb1OnlyFunction()); + // We can't realign the stack if: + // 1. Dynamic stack realignment is explicitly disabled, + // 2. This is a Thumb1 function (it's not useful, so we don't bother), or + // 3. There are VLAs in the function and the base pointer is disabled. + return (RealignStack && !AFI->isThumb1OnlyFunction() && + (!MFI->hasVarSizedObjects() || EnableBasePointer)); } bool ARMBaseRegisterInfo:: @@ -1890,7 +1896,8 @@ emitPrologue(MachineFunction &MF) const { AFI->setGPRCalleeSavedArea2Size(GPRCS2Size); AFI->setDPRCalleeSavedAreaSize(DPRCSSize); - // If we need dynamic stack realignment, do it here. + // If we need dynamic stack realignment, do it here. Be paranoid and make + // sure if we also have VLAs, we have a base pointer for frame access. if (needsStackRealignment(MF)) { unsigned MaxAlign = MFI->getMaxAlignment(); assert (!AFI->isThumb1OnlyFunction());