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From: "aldyh at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/96564] [11/12/13/14/15 Regression] New maybe use of uninitialized variable warning since r11-959 Date: Thu, 16 May 2024 14:27:52 +0000 [thread overview] Message-ID: <bug-96564-4-66BLhICePo@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-96564-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96564 --- Comment #19 from Aldy Hernandez <aldyh at gcc dot gnu.org> --- (In reply to Richard Biener from comment #17) > Handling pointer-vs-pointer in ptrs_compare_unequal isn't enough since we > have > > # PT = nonlocal null > unsigned int * x_7(D) = x; > ... > # PT = null { D.2785 } > a_9 = malloc (_2); > if (a_9 == 0B) > goto <bb 7>; [0.04%] > else > goto <bb 3>; [99.96%] > > <bb 7> [local count: 429496]: > goto <bb 6>; [100.00%] > > <bb 3> [local count: 1073312328]: > if (x_7(D) != a_9) > > so querying points-to only has to consider both pointers being NULL. Now, > I'm not sure how prange handles the above and whether or how it integrates > knowledge from flow-insensitive points-to analysis. prange currently does nothing different than what irange did. It's a first step in providing points-to and propagating the information through the CFG like we do for integer ranges. Or more precisely, prange is meant to be nothing more than a pair of integer end points (not unlimited like int_range_max), plus a value/mask pair. > > Aldy might know. > > I'm testing a patch enhancing ptrs_compare_unequal right now, also filling > in a missing bit in points-to info.
prev parent reply other threads:[~2024-05-16 14:27 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-11 7:30 [Bug middle-end/96564] New: New maybe use of uninitialized variable warning since GCC >10 stefansf at linux dot ibm.com 2020-08-11 9:27 ` [Bug middle-end/96564] " glisse at gcc dot gnu.org 2020-08-11 9:47 ` [Bug middle-end/96564] [11 Regression] New maybe use of uninitialized variable warning since r11-959 jakub at gcc dot gnu.org 2020-08-11 17:10 ` msebor at gcc dot gnu.org 2020-08-11 17:24 ` msebor at gcc dot gnu.org 2020-08-25 8:20 ` rguenth at gcc dot gnu.org 2021-01-14 9:19 ` rguenth at gcc dot gnu.org 2021-02-11 10:48 ` jakub at gcc dot gnu.org 2021-04-27 11:39 ` [Bug middle-end/96564] [11/12 " jakub at gcc dot gnu.org 2021-07-28 7:05 ` rguenth at gcc dot gnu.org 2022-04-21 7:48 ` rguenth at gcc dot gnu.org 2023-03-14 5:00 ` [Bug middle-end/96564] [11/12/13 " pinskia at gcc dot gnu.org 2023-05-29 10:03 ` [Bug middle-end/96564] [11/12/13/14 " jakub at gcc dot gnu.org 2024-03-10 22:49 ` law at gcc dot gnu.org 2024-03-11 10:23 ` rguenth at gcc dot gnu.org 2024-03-11 13:26 ` rguenth at gcc dot gnu.org 2024-03-11 15:20 ` amacleod at redhat dot com 2024-03-12 7:37 ` rguenth at gcc dot gnu.org 2024-05-16 11:23 ` [Bug middle-end/96564] [11/12/13/14/15 " rguenth at gcc dot gnu.org 2024-05-16 12:44 ` cvs-commit at gcc dot gnu.org 2024-05-16 14:27 ` aldyh at gcc dot gnu.org [this message]
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