public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/107087] [12/13 Regression] bits/stl_algobase.h:431: warning: 'void* __builtin_memcpy(void*, const void*, unsigned int)' reading between 8 and 2147483644 bytes from a region of size 4 [-Wstringop-overread] Date: Fri, 31 Mar 2023 11:36:17 +0000 [thread overview] Message-ID: <bug-107087-4-en3EFEQucV@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-107087-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107087 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Summary|[13 Regression] |[12/13 Regression] |bits/stl_algobase.h:431: |bits/stl_algobase.h:431: |warning: 'void* |warning: 'void* |__builtin_memcpy(void*, |__builtin_memcpy(void*, |const void*, unsigned int)' |const void*, unsigned int)' |reading between 8 and |reading between 8 and |2147483644 bytes from a |2147483644 bytes from a |region of size 4 |region of size 4 |[-Wstringop-overread] |[-Wstringop-overread] Status|RESOLVED |REOPENED Assignee|rguenth at gcc dot gnu.org |unassigned at gcc dot gnu.org Resolution|FIXED |--- Target Milestone|13.0 |12.3 --- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> --- Only comment#1 is fixed, the original testcase is 22_locale/money_get/cons/3.cc which still fails with the settings from comment#7 We have <bb 25> [local count: 268328082]: _187 = MEM[(struct _Rep *)&_S_empty_rep_storage].D.58774._M_length; _189 = MIN_EXPR <_170, _187>; if (_189 != 0) goto <bb 26>; [50.00%] else goto <bb 29>; [50.00%] <bb 26> [local count: 134164041]: if (_189 == 1) goto <bb 27>; [34.00%] else goto <bb 28>; [66.00%] <bb 27> [local count: 45615775]: MEM[(struct char_type *)_172] = MEM[(const struct character &)&_S_empty_rep_storage + 12]; goto <bb 29>; [100.00%] <bb 28> [local count: 88548267]: _173 = _189 * 4; __builtin_memcpy (_172, &MEM <size_type[4]> [(void *)&_S_empty_rep_storage + 12B], _173); // <--- diagnosed <bb 29> [local count: 268328083]: __negative_sign ={v} {CLOBBER}; so we know that _173 is [2, +INF] * 4 and that's enough to diagnose the call as we seem to have an idea about the source size (the embedded string length). There's an intervening operator new preventing CSE of the length of the destination and while there's a condition of != &_S_empty_rep_storage control flow converges again before this, so it seems we handle both here. It's incredibly branchy code :/
next prev parent reply other threads:[~2023-03-31 11:36 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-09-29 14:35 [Bug middle-end/107087] New: " redi at gcc dot gnu.org 2023-03-09 20:48 ` [Bug tree-optimization/107087] " redi at gcc dot gnu.org 2023-03-09 20:49 ` [Bug tree-optimization/107087] [13 Regression] " redi at gcc dot gnu.org 2023-03-15 10:00 ` rguenth at gcc dot gnu.org 2023-03-27 13:00 ` rguenth at gcc dot gnu.org 2023-03-27 13:52 ` rguenth at gcc dot gnu.org 2023-03-27 14:00 ` redi at gcc dot gnu.org 2023-03-28 13:25 ` cvs-commit at gcc dot gnu.org 2023-03-28 13:26 ` rguenth at gcc dot gnu.org 2023-03-30 8:31 ` redi at gcc dot gnu.org 2023-03-31 11:36 ` rguenth at gcc dot gnu.org [this message] 2023-03-31 11:55 ` [Bug tree-optimization/107087] [12/13 " redi at gcc dot gnu.org 2023-03-31 12:43 ` redi at gcc dot gnu.org 2023-03-31 22:45 ` cvs-commit at gcc dot gnu.org 2023-03-31 23:25 ` [Bug tree-optimization/107087] [12 " redi at gcc dot gnu.org 2023-04-27 11:50 ` rguenth at gcc dot gnu.org 2023-04-27 12:00 ` redi at gcc dot gnu.org 2023-04-29 0:41 ` sjames at gcc dot gnu.org 2023-04-29 6:56 ` redi at gcc dot gnu.org 2023-04-29 7:02 ` sjames at gcc dot gnu.org 2023-05-08 12:25 ` rguenth at gcc dot gnu.org
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=bug-107087-4-en3EFEQucV@http.gcc.gnu.org/bugzilla/ \ --to=gcc-bugzilla@gcc.gnu.org \ --cc=gcc-bugs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).