[C++11][4.9] Add missing REDUC_PLUS_EXPR case to potential_constant_expression_1.

Richard Biener richard.guenther@gmail.com
Fri Mar 15 08:51:00 GMT 2013

On Thu, Mar 14, 2013 at 10:08 PM, Marc Glisse <marc.glisse@inria.fr> wrote:
> On Thu, 14 Mar 2013, Jakub Jelinek wrote:
>> I wonder if it wouldn't be better to fold the target builtins only later
>> on
>> (e.g. guard the folding with cfun && gimple_in_ssa_p (cfun) (or if we have
>> any predicate that is set starting with gimplification or so)).
>> Having all the FEs have to deal with myriads of weird tree codes etc.
>> isn't
>> IMHO desirable.
> Wouldn't that prevent from using those builtins in constant expressions?
> That seems undesirable. Maybe an alternative could be to push some of the
> functionality from potential_constant_expression_1 to the middle-end?

True, but is that bad?

If we want to delay such folding then please don't do it with a magic flag
but instead do the folding only via fold_stmt - that is, add a new target hook
that folds a gimple call.  I bet we have only a very limited set of target call
foldings, so transitioning them all to fold gimple calls would be easy.


> --
> Marc Glisse

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