Re: [PATCH] Fixup fortran type_for_size langhook

[Paul Richard Thomas <paul dot richard dot thomas at gmail dot com>]

Dear Jakub,

This is, of course, OK for trunk.  In fact, I would say that it verges
on obvious.

Thanks for taking care of it.

Paul

On Fri, Sep 23, 2011 at 4:44 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> Hi!
>
> I've noticed with the
> 2009-05-29 ?Eric Botcazou ?<ebotcazou@adacore.com>
>
> ? ? ? ?* tree-ssa-loop-ivopts.c (strip_offset_1) <MULT_EXPR>: New case.
> ? ? ? ?(force_expr_to_var_cost) <NEGATE_EXPR>: Likewise.
> ? ? ? ?(ptr_difference_cost): Use affine combinations to compute it.
> ? ? ? ?(difference_cost): Likewise.
> ? ? ? ?(get_computation_cost_at): Compute more accurate cost for addresses
> ? ? ? ?if the ratio is a multiplier allowed in addresses.
> ? ? ? ?For non-addresses, consider that an additional offset or symbol is
> ? ? ? ?added only once.
> patch backported to 4.4-RH branch an ICE on PowerPC, where difference_cost
> calls signed_type_for, which for a BOOLEAN_TYPE returns NULL, but
> difference_cost isn't prepared for it. ?Can't reproduce it on 4.6 nor trunk,
> but most probably just because some other optimizations made the problem
> latent. ?Looking at signed_type_for and the type_for_size langhook it uses
> (yeah, I know, it isn't very much desirable to use langhooks in the
> middle-end), the langhook is documented to return a signed resp. unsigned
> type that can hold AT LEAST the requested bits and most frontends implement
> it that way, with the exception of Fortran and Go. ?And it seems lots of
> places all around the middle-end assume that for not excessively large types
> signed_type_for/unsigned_type_for will always succeed.
> This patch fixes up the Fortran FE, so that even if there is no exact match
> with a TYPE_PRECISION, if there is a wider type, the smallest of them will
> be used. ?The type_for_mode langhook on the other side must return a type
> with the requested mode exactly, so if it uses gfc_type_for_size which now
> can return wider type, it needs to check whether the returned type's
> TYPE_MODE is the requested one.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2011-09-23 ?Jakub Jelinek ?<jakub@redhat.com>
>
> ? ? ? ?* trans-types.c (gfc_type_for_size): Return wider type
> ? ? ? ?if no suitable narrower type has been found.
> ? ? ? ?(gfc_type_for_mode): Return NULL_TREE if gfc_type_for_size
> ? ? ? ?returned type doesn't have expected TYPE_MODE.
>
> --- gcc/fortran/trans-types.c.jj ? ? ? ?2011-09-05 12:28:53.000000000 +0200
> +++ gcc/fortran/trans-types.c ? 2011-09-23 11:34:44.000000000 +0200
> @@ -2791,18 +2791,29 @@ gfc_type_for_size (unsigned bits, int un
> ? ? ? if (bits == TYPE_PRECISION (intTI_type_node))
> ? ? ? ?return intTI_type_node;
> ?#endif
> +
> + ? ? ?if (bits <= TYPE_PRECISION (intQI_type_node))
> + ? ? ? return intQI_type_node;
> + ? ? ?if (bits <= TYPE_PRECISION (intHI_type_node))
> + ? ? ? return intHI_type_node;
> + ? ? ?if (bits <= TYPE_PRECISION (intSI_type_node))
> + ? ? ? return intSI_type_node;
> + ? ? ?if (bits <= TYPE_PRECISION (intDI_type_node))
> + ? ? ? return intDI_type_node;
> + ? ? ?if (bits <= TYPE_PRECISION (intTI_type_node))
> + ? ? ? return intTI_type_node;
> ? ? }
> ? else
> ? ? {
> - ? ? ?if (bits == TYPE_PRECISION (unsigned_intQI_type_node))
> + ? ? ?if (bits <= TYPE_PRECISION (unsigned_intQI_type_node))
> ? ? ? ? return unsigned_intQI_type_node;
> - ? ? ?if (bits == TYPE_PRECISION (unsigned_intHI_type_node))
> + ? ? ?if (bits <= TYPE_PRECISION (unsigned_intHI_type_node))
> ? ? ? ?return unsigned_intHI_type_node;
> - ? ? ?if (bits == TYPE_PRECISION (unsigned_intSI_type_node))
> + ? ? ?if (bits <= TYPE_PRECISION (unsigned_intSI_type_node))
> ? ? ? ?return unsigned_intSI_type_node;
> - ? ? ?if (bits == TYPE_PRECISION (unsigned_intDI_type_node))
> + ? ? ?if (bits <= TYPE_PRECISION (unsigned_intDI_type_node))
> ? ? ? ?return unsigned_intDI_type_node;
> - ? ? ?if (bits == TYPE_PRECISION (unsigned_intTI_type_node))
> + ? ? ?if (bits <= TYPE_PRECISION (unsigned_intTI_type_node))
> ? ? ? ?return unsigned_intTI_type_node;
> ? ? }
>
> @@ -2823,7 +2834,10 @@ gfc_type_for_mode (enum machine_mode mod
> ? else if (GET_MODE_CLASS (mode) == MODE_COMPLEX_FLOAT)
> ? ? base = gfc_complex_types;
> ? else if (SCALAR_INT_MODE_P (mode))
> - ? ?return gfc_type_for_size (GET_MODE_PRECISION (mode), unsignedp);
> + ? ?{
> + ? ? ?tree type = gfc_type_for_size (GET_MODE_PRECISION (mode), unsignedp);
> + ? ? ?return type != NULL_TREE && mode == TYPE_MODE (type) ? type : NULL_TREE;
> + ? ?}
> ? else if (VECTOR_MODE_P (mode))
> ? ? {
> ? ? ? enum machine_mode inner_mode = GET_MODE_INNER (mode);
>
> ? ? ? ?Jakub
>



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