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From: "tschwinge at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/101862] [C, C++] Potential '?:' diagnostic for always-true expressions in boolean context Date: Mon, 16 Aug 2021 10:22:52 +0000 [thread overview] Message-ID: <bug-101862-4-fBuk1mhzPi@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-101862-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101862 --- Comment #3 from Thomas Schwinge <tschwinge at gcc dot gnu.org> --- Thanks for your comments! (In reply to Andrew Macleod from comment #1) > I'm not sure exactly what you want to do. Neither am I! ;-) (Well, I do know "what", but not yet "how".) > The EVRP pass recognizes [...] > This seems to be too late to determine that a warning might be appropriate.. > and I'm not sure how you would figure that out from this IL. > > We have to go way back before gimple before we see the conditional > expression. > The range machinery knows what you want to know, but IM not sure how you > could use it. Its only available once we go into SSA. Idea: preserve the original front end AST (or whatever is appropriate), for "potential diagnostics" ("delayed diagnostics"?), and then (re-)evaluate once we have VR information (and whatever else is necessary). > we usually rejoice when we can fold asserts away :-) A classic case of tuning for code generation vs. diagnostics. ;-)
prev parent reply other threads:[~2021-08-16 10:22 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-11 9:19 [Bug middle-end/101862] New: " tschwinge at gcc dot gnu.org 2021-08-11 17:42 ` [Bug middle-end/101862] " amacleod at redhat dot com 2021-08-13 5:25 ` egallager at gcc dot gnu.org 2021-08-16 10:22 ` tschwinge at gcc dot gnu.org [this message]
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