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/102446] [9/10/11/12 Regression] wrong code at -O3 on x86_64-linux-gnu Date: Wed, 22 Sep 2021 10:56:26 +0000 [thread overview] Message-ID: <bug-102446-4-JMTzzXmVwC@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-102446-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102446 --- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- void m() { int aa = 0, i = 0; for (; i < 3; i++) if (k < 0) aa |= *j; Dump of assembler code for function m: 0x0000000000400540 <+0>: mov 0x200b16(%rip),%edi # 0x60105c <k> 0x0000000000400546 <+6>: mov 0x200b13(%rip),%rax # 0x601060 <j> 0x000000000040054d <+13>: sar $0x1f,%edi => 0x0000000000400550 <+16>: and (%rax),%edi 0x0000000000400552 <+18>: cmpw $0x0,0x200af6(%rip) # 0x601050 <d> so we're loading *j before checking k < 0. On GIMPLE that's OK: <bb 2> [local count: 268435456]: k.5_1 = k; j.6_2 = j; if (k.5_1 < 0) goto <bb 3>; [41.00%] else goto <bb 4>; [59.00%] <bb 3> [local count: 110058537]: j.6__lsm0.31_28 = *j.6_2; <bb 4> [local count: 268435456]: # aa_9 = PHI <j.6__lsm0.31_28(3), 0(2)> but RTL if-conversion makes the load unconditional. (insn 13 12 35 3 (set (reg/v:SI 89 [ j.6__lsm0.31 ]) (mem:SI (reg/f:DI 83 [ j.6_2 ]) [1 *j.6_2+0 S4 A32])) 77 {*movsi_internal} (expr_list:REG_DEAD (reg/f:DI 83 [ j.6_2 ]) (nil))) I don't see any flags marking it as not trapping?
next prev parent reply other threads:[~2021-09-22 10:56 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-09-22 9:00 [Bug tree-optimization/102446] New: " zhendong.su at inf dot ethz.ch 2021-09-22 10:50 ` [Bug tree-optimization/102446] " rguenth at gcc dot gnu.org 2021-09-22 10:54 ` [Bug tree-optimization/102446] [9/10/11/12 Regression] " jakub at gcc dot gnu.org 2021-09-22 10:56 ` Jan Hubicka 2021-09-22 10:56 ` rguenth at gcc dot gnu.org [this message] 2021-09-22 10:56 ` hubicka at ucw dot cz 2021-09-22 10:57 ` [Bug rtl-optimization/102446] " rguenth at gcc dot gnu.org 2021-09-22 10:57 ` rguenth at gcc dot gnu.org 2021-09-22 11:01 ` jakub at gcc dot gnu.org 2021-09-22 11:02 ` jakub at gcc dot gnu.org 2021-09-22 11:11 ` pinskia at gcc dot gnu.org 2021-09-22 11:29 ` jakub at gcc dot gnu.org 2022-01-30 2:04 ` pinskia at gcc dot gnu.org 2022-01-30 12:34 ` jakub at gcc dot gnu.org 2022-01-30 20:48 ` pinskia at gcc dot gnu.org 2022-05-27 9:46 ` [Bug rtl-optimization/102446] [10/11/12/13 " rguenth at gcc dot gnu.org 2022-06-28 10:46 ` jakub at gcc dot gnu.org 2022-07-29 12:22 ` [Bug rtl-optimization/102446] [10/11 " rguenth at gcc dot gnu.org 2022-07-29 12:44 ` jakub at gcc dot gnu.org 2022-07-29 12:45 ` jakub at gcc dot gnu.org 2023-07-07 10:41 ` [Bug rtl-optimization/102446] [11 " 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-102446-4-JMTzzXmVwC@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).