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

[Kai Tietz]

2011/5/15 Kai Tietz <ktietz70@googlemail.com>:
> 2011/5/15 Eric Botcazou <ebotcazou@adacore.com>:
>>> 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.
>
> Yes, I will adjust comment here about ADA. Code for ADA looks sane.
> Just one nit I saw in trans.c, which might be a cause here.
>
>>> 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.
>
> With this patch (which would describe why it gimplifier sees
> integer-type nodes here):
>
> Index: gcc/gcc/ada/gcc-interface/trans.c
> ===================================================================
> --- gcc.orig/gcc/ada/gcc-interface/trans.c      2011-05-12
> 20:06:01.000000000 +0200
> +++ gcc/gcc/ada/gcc-interface/trans.c   2011-05-15 15:33:32.305516200 +0200
> @@ -7101,7 +7110,7 @@ convert_with_check (Entity_Id gnat_type,
>     {
>       /* Ensure GNU_EXPR only gets evaluated once.  */
>       tree gnu_input = gnat_protect_expr (gnu_result);
> -      tree gnu_cond = integer_zero_node;
> +      tree gnu_cond = boolean_false_node;
>       tree gnu_in_lb = TYPE_MIN_VALUE (gnu_in_basetype);
>       tree gnu_in_ub = TYPE_MAX_VALUE (gnu_in_basetype);
>       tree gnu_out_lb = TYPE_MIN_VALUE (gnu_base_type);
>
> I was able to do a bootstrap for ada and run 'make check-ada' without
> seeing gimplification errors.
>
> The only failure I see in testrun is 'cxg2001.adb' test with 'GCC
> error: in compensate_edge, at reg-stach.c:2781' Error detect around
> cxg2001.adb:322:5.  But well, this bug seems to me unrelated here to
> gimplication. But maybe I am wrong here.
>
> Regards,
> Kai

PS: There are more places to fix, I will sent tomorrow a full patch
for this after bootstrap and testsuite-run was completetly successful.
 I saw in later gnat.dg the described error (but no more the truth-not
issue). So I was a bit to early to post here.

Regards,
Kai