On Sat, Jun 6, 2015 at 1:34 PM, Marc Glisse <marc.gli...@inria.fr> wrote:
> Hello,
>
> as discussed around
> https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00041.html
> we are currently guessing the type of a?b:c incorrectly. This does not
> affect current simplifications, because the only 'cond' in output patterns
> are at the outermost level, so their type is forced to 'type' and never
> guessed. Indeed, the patch does not change the generated *-match.c. It would
> allow removing an explicit cond:itype in a patch posted by Jeff.
>
> I tested it on a dummy .pd file containing:
> (simplify
> (plus @0 (plus @1 @2))
> (negate (cond @0 @1 @2)))
>
> and the generated files differ by:
>
> - res = fold_build3_loc (loc, COND_EXPR, TREE_TYPE (ops1[0]), ops1[0],
> ops1[1], ops1[2]);
> + res = fold_build3_loc (loc, COND_EXPR, TREE_TYPE (ops1[1]), ops1[0],
> ops1[1], ops1[2]);
>
> (and something similar for gimple)
>
> I wondered about using something like
> VOID_TYPE_P (TREE_TYPE (ops1[1])) ? TREE_TYPE (ops1[2]) : TREE_TYPE
> (ops1[1])
> but I don't think that will be necessary.
Yeah, I think we can't currently match this anyway.
> Bootstrap is currently broken on many platforms with comparison failures,
> but since it went that far and generated the same *-match.c files, that
> seems sufficient testing.
Ok. (this is indeed how I test genmatch.c patches - look at differences
in generated {generic,gimple}-match.c and play with toy patterns and
check their handling)
Thanks,
Richard.
> 2015-06-08 Marc Glisse <marc.gli...@inria.fr>
>
> * genmatch.c (expr::gen_transform): For conditions, guess the type
> from the second operand.
>
> --
> Marc Glisse
> Index: gcc/genmatch.c
> ===================================================================
> --- gcc/genmatch.c (revision 224186)
> +++ gcc/genmatch.c (working copy)
> @@ -1702,20 +1702,27 @@ expr::gen_transform (FILE *f, const char
> type = optype;
> }
> else if (is_a <operator_id *> (operation)
> && !strcmp (as_a <operator_id *> (operation)->tcc,
> "tcc_comparison"))
> {
> /* comparisons use boolean_type_node (or what gets in), but
> their operands need to figure out the types themselves. */
> sprintf (optype, "boolean_type_node");
> type = optype;
> }
> + else if (*operation == COND_EXPR
> + || *operation == VEC_COND_EXPR)
> + {
> + /* Conditions are of the same type as their first alternative. */
> + sprintf (optype, "TREE_TYPE (ops%d[1])", depth);
> + type = optype;
> + }
> else
> {
> /* Other operations are of the same type as their first operand. */
> sprintf (optype, "TREE_TYPE (ops%d[0])", depth);
> type = optype;
> }
> if (!type)
> fatal ("two conversions in a row");
>
> fprintf (f, "{\n");
>
