https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80588
Ivan Sučić <sucicf1 at outlook dot com> changed:
What |Removed |Added
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CC| |sucicf1 at outlook dot com
--- Comment #2 from Ivan Sučić <sucicf1 at outlook dot com> ---
By me everything works but test2b. When I in match.pd remove /* Try to fold
(type) X op CST -> (type) (X op ((type-x) CST))
when profitable.
For bitwise binary operations apply operand conversions to the
binary operation result instead of to the operands. This allows
to combine successive conversions and bitwise binary operations.
We combine the above two cases by using a conditional convert. */
(for bitop (bit_and bit_ior bit_xor)
(simplify
(bitop (convert @0) (convert? @1))
(if (((TREE_CODE (@1) == INTEGER_CST
&& INTEGRAL_TYPE_P (TREE_TYPE (@0))
&& int_fits_type_p (@1, TREE_TYPE (@0)))
|| types_match (@0, @1))
/* ??? This transform conflicts with fold-const.c doing
Convert (T)(x & c) into (T)x & (T)c, if c is an integer
constants (if x has signed type, the sign bit cannot be set
in c). This folds extension into the BIT_AND_EXPR.
Restrict it to GIMPLE to avoid endless recursions. */
&& (bitop != BIT_AND_EXPR || GIMPLE)
&& (/* That's a good idea if the conversion widens the operand, thus
after hoisting the conversion the operation will be narrower. */
TYPE_PRECISION (TREE_TYPE (@0)) < TYPE_PRECISION (type)
/* It's also a good idea if the conversion is to a non-integer
mode. */
|| GET_MODE_CLASS (TYPE_MODE (type)) != MODE_INT
/* Or if the precision of TO is not the same as the precision
of its mode. */
|| !type_has_mode_precision_p (type)))
(convert (bitop @0 (convert @1))))))
then test2b optimizes correct. The question is why? In match.pd what does
convert?
