public inbox for gcc-bugs@sourceware.org help / color / mirror / Atom feed
From: "amker at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/66396] [6 regression] FAIL: gcc.dg/graphite/run-id-pr47593.c execution test Date: Thu, 04 Jun 2015 04:13:00 -0000 [thread overview] Message-ID: <bug-66396-4-Y1jwq0rrJ0@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-66396-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66396 --- Comment #3 from amker at gcc dot gnu.org --- Interesting case. I know nothing about graphite, but I guess the case is fixed in patch for PR47653 by skipping graphite transofromation on loops in specific forms. The skip mechanism is kind of nullified by the overflow change. But as far as I can see, we shouldn't skip graphite transformation on the case in the first place because it looks good to me. See dumps before graphite pass: bar () { _Bool j_lsm.8; int j_lsm.7; int * y; int * x; char * p; int i; int j; struct Foo f; unsigned int j.2_11; int j.1_13; int * * _15; int * _16; int _17; int j.0_31; <bb 2>: i = 1; x = &i; y = &j; f.p = &y; f.q = &x; <bb 3>: # p_27 = PHI <&f(2), p_12(4)> # j.0_31 = PHI <0(2), j.1_13(4)> p_12 = p_27 + 1; j.1_13 = j.0_31 + 1; j.2_11 = (unsigned int) j.1_13; if (j.2_11 <= 3) goto <bb 4>; else goto <bb 5>; <bb 4>: goto <bb 3>; <bb 5>: p_25 = &f + 4; j = 4; _15 = MEM[(int * * *)p_25]; _16 = *_15; _17 = *_16; f ={v} {CLOBBER}; j ={v} {CLOBBER}; i ={v} {CLOBBER}; x ={v} {CLOBBER}; y ={v} {CLOBBER}; return _17; } graphite transforms it infor below shape: bar () { _Bool j_lsm.8; int j_lsm.7; int * y; int * x; char * p; int i; int j; struct Foo f; int * * _15; int * _16; int _17; <bb 2>: i = 1; x = &i; y = &j; f.p = &y; f.q = &x; p_25 = &f + 4; j = 4; _15 = MEM[(int * * *)p_25]; _16 = *_15; _17 = *_16; f ={v} {CLOBBER}; j ={v} {CLOBBER}; i ={v} {CLOBBER}; x ={v} {CLOBBER}; y ={v} {CLOBBER}; return _17; } It is dce4 pass that deletes the bounch of initialization code at beginning of bb 2. dce4.dump is as below: bar () { _Bool j_lsm.8; int j_lsm.7; int * y; int * x; char * p; int i; int j; struct Foo f; int * * _15; int * _16; int _17; <bb 2>: p_25 = &f + 4; j = 4; _15 = MEM[(int * * *)p_25]; _16 = *_15; _17 = *_16; f ={v} {CLOBBER}; j ={v} {CLOBBER}; i ={v} {CLOBBER}; x ={v} {CLOBBER}; y ={v} {CLOBBER}; return _17; } I thought this was a strict-aliasing issue, but specifying "-fno-strict-aliasing" doesn't give any difference.
next prev parent reply other threads:[~2015-06-04 4:13 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-06-03 11:27 [Bug tree-optimization/66396] New: " schwab@linux-m68k.org 2015-06-03 11:29 ` [Bug tree-optimization/66396] " schwab@linux-m68k.org 2015-06-03 12:11 ` rguenth at gcc dot gnu.org 2015-06-03 13:04 ` rguenth at gcc dot gnu.org 2015-06-04 4:13 ` amker at gcc dot gnu.org [this message] 2015-06-04 4:13 ` amker at gcc dot gnu.org 2015-06-04 11:15 ` rguenth at gcc dot gnu.org 2015-06-08 11:51 ` rguenth at gcc dot gnu.org 2015-06-08 12:18 ` rguenth at gcc dot gnu.org 2015-06-09 7:52 ` rguenth at gcc dot gnu.org 2015-06-09 8:22 ` 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-66396-4-Y1jwq0rrJ0@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).