On Thu, 9 Jan 2014, Jakub Jelinek wrote: > On Thu, Jan 09, 2014 at 01:30:53PM +0100, Richard Biener wrote: > > > gimplify_modify_expr has: > > > > > > if (!gimple_call_noreturn_p (assign)) > > > gimple_call_set_lhs (assign, *to_p); > > > > Ok, it seems to be too early then - move it after the folding. > > That wouldn't help all the other early calls of fold_stmt though. > E.g. lower_omp. Plus, even in gimplify_modify_expr, doing it > after fold_stmt would mean having to walk all stmts created by the folding?, > check if they are calls (because a call can fold into nothing or something > completely different). Isn't it better then fold_stmt does that instead?
Hmm, maybe. Not sure why we are this anal about requiring noreturn calls not to have a LHS. But if we require callers in SSA form to update the stmt and properly cleanup the cfg if fold_stmt returns true then it's reasonable to require at least "something" for callers from non-SSA/CFG code. That is, I don't like this special-casing. If so, then rather don't fold at this point - thus if (... !inplace && in_ssa_form (cfun) ...) (or rather if we have a CFG - cfun && cfun->curr_properties & PROP_cfg). Richard.
