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Re: Problem with accessing built-ins from Fortran front-end
- From: Jakub Jelinek <jakub at redhat dot com>
- To: FX <fxcoudert at gmail dot com>
- Cc: Fortran List <fortran at gcc dot gnu dot org>, GCC Development <gcc at gcc dot gnu dot org>
- Date: Fri, 26 Sep 2014 10:56:44 +0200
- Subject: Re: Problem with accessing built-ins from Fortran front-end
- Authentication-results: sourceware.org; auth=none
- References: <91DCE093-1239-4C0D-9F41-D3BDE9887F53 at gmail dot com>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Fri, Sep 26, 2014 at 10:29:57AM +0200, FX wrote:
> Hi,
>
> Iâm trying to make the Fortran front-end emit calls to some builtins we donât currently use (isfinite, isnormal). However, trying to use the same code as isnan doesnât work at all. Our gfc_define_builtin does three things:
>
> decl = add_builtin_function (name, type, code, BUILT_IN_NORMAL, library_name, NULL_TREE);
> set_call_expr_flags (decl, attr);
> set_builtin_decl (code, decl, true);
>
> While doing so works with isnan, it fails with isfinite or isnormal. When I try to, I get an ICE in tree checking:
>
> * frame #0: 0x0000000100c02338 f951`build_call_expr_loc_array(loc=0, fndecl=0x0000000000000000, n=2, argarray=0x00007fff5fbfeb20) + 24 at tree.h:2846
> frame #1: 0x0000000100c0259a f951`build_call_expr(fndecl=<unavailable>, n=<unavailable>) + 186 at tree.c:10550
> frame #2: 0x000000010046f671 f951`fold_builtin_interclass_mathfn(loc=<unavailable>, fndecl=<unavailable>, arg=0x000000014340c990) + 337 at builtins.c:9393
> frame #3: 0x0000000100485e34 f951`fold_builtin_1(loc=260, fndecl=0x0000000143449360, arg0=0x000000014340c990, ignore=<unavailable>) + 2964 at builtins.c:10050
> frame #4: 0x000000010049030c f951`fold_builtin_n(loc=<unavailable>, fndecl=<unavailable>, args=<unavailable>, nargs=<unavailable>, ignore=<unavailable>) + 1116 at builtins.c:10409
> frame #5: 0x0000000100491c33 f951`fold_builtin_call_array(loc=260, type=0x0000000143405690, fn=0x000000014351fc40, n=1, argarray=0x00007fff5fbfeeb0) + 355 at builtins.c:10575
> frame #6: 0x0000000100c024c5 f951`build_call_expr_loc(loc=<unavailable>, fndecl=<unavailable>, n=<unavailable>) + 181 at tree.c:10533
>
>
> I donât understand how the middle-end builtins decl should work, would someone have a hint of how to fix this?
Just look what foold_builtin_interclass_mathfn does:
isfinite(x) -> islessequal(fabs(x),DBL_MAX)
isnormal(x) -> isgreaterequal(fabs(x),DBL_MIN) & islessequal(fabs(x),DBL_MAX)
Thus, the middle-end assumes that if you have __builtin_{isfinite,isnormal},
you also have __builtin_is{less,greater}equal builtins too.
Just create those too and you'll be fine (they are also typegeneric, like
__builtin_is{finite,normal}), i.e. they take ... arguments and the FE is
supposed to verify they are ok (or, if the FE creates them artificially, it
will ensure that too).
Jakub