From: Feng Xue Date: Mon, 5 Aug 2024 07:23:56 +0000 (+0800) Subject: vect: Allow unsigned-to-signed promotion in vect_look_through_possible_promotion... X-Git-Tag: basepoints/gcc-16~6816 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3c089ee5d5a86cab0b27c69b96c4354c496520ac;p=thirdparty%2Fgcc.git vect: Allow unsigned-to-signed promotion in vect_look_through_possible_promotion [PR115707] The function fails to figure out root definition if casts involves more than two promotions with sign change as: long a = (long)b; // promotion cast -> int b = (int)c; // promotion cast, sign change -> unsigned short c = ...; For this case, the function thinks the 2nd cast has different sign as the 1st, so stop looking through, while "unsigned short -> integer" is a nature sign extension. 2024-08-05 Feng Xue gcc/ PR tree-optimization/115707 * tree-vect-patterns.cc (vect_look_through_possible_promotion): Allow unsigned-to-signed promotion. --- diff --git a/gcc/tree-vect-patterns.cc b/gcc/tree-vect-patterns.cc index 4674a16d15f..b2c83cfd219 100644 --- a/gcc/tree-vect-patterns.cc +++ b/gcc/tree-vect-patterns.cc @@ -434,7 +434,9 @@ vect_look_through_possible_promotion (vec_info *vinfo, tree op, sign of the previous promotion. */ if (!res || TYPE_PRECISION (unprom->type) == orig_precision - || TYPE_SIGN (unprom->type) == TYPE_SIGN (op_type)) + || TYPE_SIGN (unprom->type) == TYPE_SIGN (op_type) + || (TYPE_UNSIGNED (op_type) + && TYPE_PRECISION (op_type) < TYPE_PRECISION (unprom->type))) { unprom->set_op (op, dt, caster); min_precision = TYPE_PRECISION (op_type);