2015-08-27 12:34 GMT+02:00 Richard Biener <richard.guent...@gmail.com>: > On Thu, Aug 27, 2015 at 11:21 AM, Kai Tietz <ktiet...@googlemail.com> wrote: >> 2015-08-27 4:57 GMT+02:00 Jason Merrill <ja...@redhat.com>: >>> Why does fold_simple fold so many patterns? I thought we wanted something >>> that would just fold conversions and negations of constant values. >> >> Yes, initial variant was handling much less patterns. But actually we >> need for functions (eg. like build_vec_init in init.c) a simple >> routine to perform basic constant-value arithmetics (sizeof * / + - >> trunc, etc) to avoid call of maybe_constant_value. Also for >> overflow-diagnostics we want at least to resolve such simple patterns >> for constant-values only. We could change those calls to use >> maybe_constant_value instead, but the overhead (and some of its >> folding) leads much further then working on constant-values only (as >> fold_simple does). >> >> It might be that we can remove the ternary vector-cond expression from >> this routine, The cond-expr itself seems to be necessary to resolve >> patterns like (1 == 1 ? 32 : 64), which can appear pretty often via >> macro-code. I will check if I what patterns I can remove here. > > Note that fold-const.c has constant-only folding routines (handling only > constant operands). const_unop, const_binop (no const_ternop split > out yet). > > Richard.
Thanks for the point. I will take a look into cons_unop/binop. I just expect that this routines would fail if they get c++-expressions, aren't they? >>> Jason Kai
