Hi, > >> > If a pointer typed use is plainly value passed to a func call, it is > >> > not an address use, right? But as you said, x86 lea may help here. > >> > >> But that's what you are matching ... (well, for builtins you know > >> will expand that to a memory reference). > >> > >> What I dislike in the patch is the special-casing of some builtins > >> via a target hook. I'd rather say treat all internal functions and > >> all target builtins that way. Or simply all addresses. > > > > unless the architecture has lea-type instruction to compute the address, > > computing say b+4*i incurs some cost, while if mem[b+4*i] is accessed, the > > computation is for free. Thus, it does not make sense to treat the address > > computations the same way as memory references (or to treat all functions > > the same way as builtins which translate to memory references), > > I understand that, but I think the patch tries to improve code generation > not by changing the set of IVs used (thus adjust cost considerations) > but by changing the way it rewrites certain address uses.
actually, the costs are adjusted in the patch -- the address calculations for the handled builtins are recorded as USE_ADDRESS (not as USE_NONLINEAR_EXPR), so that their costs are calculated in the same way as for memory references, Zdenek
