Hi Richard, > Normally we should only put two instructions in the same define_insn > if there's a specific ABI or architectural reason for not separating > them. Doing it purely for optimisation reasons is going against the > general direction of travel. So I think the first question is: why > don't we simply delay the split until after reload instead, since > that's the more normal way of handling this kind of thing?
Well there are no optimizations that benefit from them being split, and there is no gain from scheduling them independently. Keeping them together means the linker could perform relaxations on the pair without adding new relocations. So if we split after reload we'd still want to keep them together. > This should just be represented as: > > (set (reg:PTR R) (symbol_ref:PTR S)) > > and go through the normal move patterns. Yes that should be feasible. Note the UNSPEC is unnecessary even in the original pattern - given it uses the standard HIGH operator for GOT accesses, we can also use LO_SUM for the 2nd part since the indirection is hidden. Cheers, Wilco
