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. > Jason Kai
