https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103194
--- Comment #10 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #9)
> (In reply to H.J. Lu from comment #6)
> > Created attachment 51785 [details]
> > The v2 incomplete patch
> >
> > Hongtao, please finish it. Thanks.
>
> I'm trying to handle narrowing part in match.pd and add else return; when
> precision is not equal.
>
> (for bit_op (bit_and bit_xor bit_ior)
> (simplify
> (bit_op (convert@0 @1) (convert@2 @3))
> (if (INTEGRAL_TYPE_P (type)
> && INTEGRAL_TYPE_P (TREE_TYPE (@1))
> && tree_nop_conversion_p (TREE_TYPE (@1), TREE_TYPE (@3))
> && single_use (@0)
> && single_use (@2)
> && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@1)))
> (with { tree type1 = TREE_TYPE (@1); }
> (convert (bit_op @1 (convert:type1 @3)))))))
>
> (for bit_op (bit_and bit_xor bit_ior)
> (simplify
> (bit_op (convert@0 @1) INTEGER_CST@2)
> (if (INTEGRAL_TYPE_P (type)
> && INTEGRAL_TYPE_P (TREE_TYPE (@1))
> && single_use (@0)
> && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (@1)))
> (convert (bit_op @1 { fold_convert (TREE_TYPE (@1), @2); })))))
hmm, cause infinite loop because of
/* 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.
??? We don't do it for BOOLEAN_TYPE or ENUMERAL_TYPE because they
very likely don't have maximal range for their precision and this
transformation effectively doesn't preserve non-maximal ranges. */
if (TREE_CODE (type) == INTEGER_TYPE
&& TREE_CODE (op0) == BIT_AND_EXPR
&& TREE_CODE (TREE_OPERAND (op0, 1)) == INTEGER_CST)
