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Re: [patch gimplifier]: Make sure TRUTH_NOT_EXPR has boolean_type_node type and argument


> Well, I mean by artificial here, that gimplification is done via
> gimplify_expr API. As FE and ME have here different assumptions.  The
> ME uses internally most boolean_type_node and IMHO it should be the
> variant used there. As this conversation to a single boolean_type
> (with recast to result FE's boolean type on demand) has some
> advantages on optimization passes.  Additionally it simplifies logic
> in passes on types.  For example there are some expressions, which are
> in general unexpected in ME as they are transformed in gimplification
> (like TRUTH_ANDIF/ORIF_EXPR).  By adding tree manual, you might cause
> the same issue as for the logical-expression showing up now.

OK, then that's definitely not the case for Ada, so the comment is incorrect.

> Well, this patch might be an alternative, but I see here potential
> issues in such none-gimplified expressions for comparision and logical
> not, which not necessariily have BOOLEAN_TYPE.  See here the code for
> fold_truth_not (and some other places) in fold-const.  So I think, as
> long as we have here external gimplication it is more save to check
> just for integral-kind.

Note that, even without "external gimplication", we still have integral types 
down to the tree-cfg.c check.  Take ACATS c52103x at -O0.  The Ada FE hands 
over a valid TRUTH_AND_EXPR, i.e. (BOOLEAN_TYPE, BOOLEAN_TYPE, BOOLEAN_TYPE) 
but the gimplifier builds a (BOOLEAN_TYPE, INTEGER_TYPE, BOOLEAN_TYPE) as it 
strips, then adds, then re-strips a cast to BOOLEAN_TYPE in gimplify_expr.

-- 
Eric Botcazou


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