On 20 December 2010 19:30, Jeff Law <l...@redhat.com> wrote: > On 12/20/10 01:47, Mohamed Shafi wrote: >> >> >>> I think this is a case where you're going to need a secondary reload to >>> force the immediate into a register if the destination is a non-symbolic >>> MEM >>> or a pseudo without a hard reg and its equivalent address is >>> non-symbolic. >>> >> I am not sure how i should be implementing this. >> Currently in define_expand for move i have code to force the >> immediate value into a register if the destination is not a symbolic >> address. If i understand correctly this is the only place where i can >> decide what to do with the source depending on the destination. right? > > Just changing the movxx expander is not sufficient since for this case you > do not know until reload time whether or not a particular insn needs an > extra register to implement the move. That's the whole point of the > secondary reload mechanism -- to allow you to allocate a scratch register > during reloading to handle oddball cases like this. > > > In your secondary reload code you'll need to check for the case where the > destination is a MEM and the source is an unallocated pseudo with a constant > equivalent and return a suitable register class for that case. > Jeff, thanks for the reply. I didn't know that you could do that in TARGET_SECONDARY_RELOAD hook. Can you point me to some target that does this - figuring out what the destination is based on the source or vice versa. In my case only the address operand comes into TARGET_SECONDARY_RELOAD hook during the reload pass. I am not sure how to find out the source for the pattern which has this particular address as the destination.
Sorry for the trouble. Shafi
