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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/100864] (a&!b) | b is not opimized to a | b for comparisons Date: Mon, 14 Jun 2021 22:04:39 +0000 [thread overview] Message-ID: <bug-100864-4-Y5dPjjMA8l@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-100864-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100864 --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So what is done for A && !B (and A || !B), is the following: /* Simple range test simplifications. */ /* A < B || A >= B -> true. */ (for test1 (lt le le le ne ge) test2 (ge gt ge ne eq ne) (simplify (bit_ior:c (test1 @0 @1) (test2 @0 @1)) (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) || VECTOR_INTEGER_TYPE_P (TREE_TYPE (@0))) { constant_boolean_node (true, type); }))) /* A < B && A >= B -> false. */ (for test1 (lt lt lt le ne eq) test2 (ge gt eq gt eq gt) (simplify (bit_and:c (test1 @0 @1) (test2 @0 @1)) (if (INTEGRAL_TYPE_P (TREE_TYPE (@0)) || VECTOR_INTEGER_TYPE_P (TREE_TYPE (@0))) { constant_boolean_node (false, type); }))) But this could be expanded to other non-integer types. For float types e.g (with -ffast-math): int f(float a, float b) { int c = a == b; int d = a != b; return c & d; } Is not optimized until reassoc1. I will change that to be similar what I Have too.
next prev parent reply other threads:[~2021-06-14 22:04 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-01 23:48 [Bug tree-optimization/100864] New: (a&!b) | b is not opimized to a | b for conditionals pinskia at gcc dot gnu.org 2021-06-02 1:33 ` [Bug tree-optimization/100864] (a&!b) | b is not opimized to a | b for comparisons pinskia at gcc dot gnu.org 2021-06-02 2:05 ` pinskia at gcc dot gnu.org 2021-06-02 8:09 ` rguenth at gcc dot gnu.org 2021-06-05 1:21 ` pinskia at gcc dot gnu.org 2021-06-14 22:04 ` pinskia at gcc dot gnu.org [this message] 2023-05-24 0:09 ` pinskia at gcc dot gnu.org 2023-07-22 23:28 ` pinskia at gcc dot gnu.org 2023-07-29 19:10 ` pinskia at gcc dot gnu.org 2023-07-31 17:12 ` cvs-commit at gcc dot gnu.org 2023-07-31 17:14 ` pinskia at gcc dot gnu.org
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