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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/24021] VRP does not work with floating points Date: Thu, 10 Feb 2022 12:02:03 +0000 [thread overview] Message-ID: <bug-24021-4-2fSrIUx5ww@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-24021-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24021 --- Comment #16 from Jakub Jelinek <jakub at gcc dot gnu.org> --- But just tracking those fpclassify/signbit properties wouldn't be enough, because in many cases e.g. whether something can be infinite or not will depend on more precise value ranges. If we track just a bitmask, can the value be: zero subnormal normal infinite qNaN sNaN have positive signbit have negative signbit then even on simple multiplication or addition we'll need to assume from normal * normal or normal + normal that it can be infinite. When we know that one operand is [-15.123 - epsilon, 23.152 + epsilon] and the other is [256.0 - epsilon, 512.0 + epsilon], we actually can find out the result will not be infinite etc. But sure, tracking in a bitmask the above properties in addition to some approximate range is useful.
next prev parent reply other threads:[~2022-02-10 12:02 UTC|newest] Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-24021-4@http.gcc.gnu.org/bugzilla/> 2021-08-25 20:29 ` amacleod at redhat dot com 2022-02-07 16:07 ` aldyh at gcc dot gnu.org 2022-02-09 16:35 ` aldyh at gcc dot gnu.org 2022-02-09 17:04 ` law at gcc dot gnu.org 2022-02-09 17:27 ` aldyh at gcc dot gnu.org 2022-02-09 17:29 ` vincent-gcc at vinc17 dot net 2022-02-09 17:31 ` vincent-gcc at vinc17 dot net 2022-02-09 18:30 ` jakub at gcc dot gnu.org 2022-02-09 18:31 ` amacleod at redhat dot com 2022-02-09 18:35 ` amacleod at redhat dot com 2022-02-09 19:05 ` vincent-gcc at vinc17 dot net 2022-02-10 9:33 ` rguenth at gcc dot gnu.org 2022-02-10 12:02 ` jakub at gcc dot gnu.org [this message] 2022-02-10 12:21 ` rguenther at suse dot de 2022-02-10 14:17 ` vincent-gcc at vinc17 dot net 2022-04-05 19:34 ` amacleod at redhat dot com 2022-04-06 9:34 ` aldyh at gcc dot gnu.org 2022-04-06 9:46 ` jakub at gcc dot gnu.org 2022-04-06 9:57 ` aldyh at gcc dot gnu.org 2022-04-06 10:30 ` aldyh at gcc dot gnu.org 2022-04-06 10:47 ` jakub at gcc dot gnu.org 2022-08-01 13:27 ` aldyh at gcc dot gnu.org 2022-08-01 14:30 ` aldyh at gcc dot gnu.org 2022-11-08 15:54 ` cvs-commit at gcc dot gnu.org 2022-11-08 15:57 ` aldyh at gcc dot gnu.org 2022-11-28 22:15 ` pinskia at gcc dot gnu.org [not found] <bug-24021-6528@http.gcc.gnu.org/bugzilla/> 2005-10-23 23:43 ` pinskia at gcc dot gnu dot org
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