Setting ARM PIC register (Was: RE: GCC 4.5.0 Status Report (2009-05-05))

[Joern Rennecke]

Michael Matz wrote:
>> The easiest solution would be to just make a note that you need the  
>> PIC register and then, when expanding the prologue emit the  
>> necessary instructions.  IMO that makes sense as PIC register setup  
>> usually is something the prologue does, like all the other register  
>> setups necessary.

Richard Earnshaw:
> That won't work because the PIC register on ARM is a pseudo, so
> generating it during prologue generation is too late.  It needs to exist
> before data flow analysis starts on the RTL.

How about emitting a set at each place the PIC register is needed,
and making sure that gcse will will common these sets where
appropriate?