Commit: MSP430: Add wakeup function attribute

[Nick Clifton]

Hi Guys,

  I have applied the patch below to add support for a wakeup function
  attribute to the MSP430 backend.  The wakeup attribute applies to
  interrupt functions, and it makes them wake the processor from low
  power sleep states when the interrupt handler exits.

Cheers
  Nick

gcc/ChangeLog
2013-12-13  Nick Clifton  <ni...@redhat.com>

        * config/msp430/msp430.c (is_wakeup_func): New function.  Returns
        true if the current function has the wakeup attribute.
        (msp430_start_function): Note if the function has the wakeup
        attribute.
        (msp430_attribute_table): Add wakeup attribute.
        (msp430_expand_epilogue): Add support for wakeup functions.
        * config/msp430/msp430.md (disable_interrupts): Emit a NOP after
        the DINT instruction.
        * doc/extend.texi: Document the wakeup attribute.