"Roland Persson" <[EMAIL PROTECTED]> writes: > For example, I have an add instruction that can add a 32-bit integer (with > or without sign extension) to a 64-bit operand and store the result as 64 > bits. > > C code like: > __int64_t a = 1; > int b = 2; > a += b; > > will generate code that sign or zero extends b into a 64 bit operand and > then apply the adddi3 pattern. > > I've unsuccessfully tried to figure out how to do this from the gcc > internals documentation and looking at some other ports. Some hints to get > me going in the right direction would be much appreciated. > > I've tried adding unnamed patterns for these instructions, using > zero_extend or sign_extend but I guess those will not get used because the > generation has already applied the adddi3 pattern when it generates the RTL > in the first place.
Adding unnamed patterns is correct. Although they won't be used when expanding trees into RTL, they will be available for use by the combine pass. Ian
