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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/51644] [4.7 Regression] va_list vs. warning: ‘noreturn’ function does return is not fixable Date: Wed, 21 Dec 2011 09:53:00 -0000 [thread overview] Message-ID: <bug-51644-4-1iFBYrdsu9@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-51644-4@http.gcc.gnu.org/bugzilla/> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51644 --- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-12-21 09:51:45 UTC --- Caused by r181172 aka TREE_CLOBBER_P. The problem is that we have before *.cfg: __builtin_va_start (&args, 0); b (s, &args); __builtin_va_end (&args); finally_tmp.0 = 1; <D.2917>: args = {CLOBBER}; switch (finally_tmp.0) <default: <D.2921>, default: <D.2921>, case 1: <D.2918>> <D.2918>: goto <D.2919>; <D.2919>: return; <D.2920>: finally_tmp.0 = 0; goto <D.2917>; <D.2921>: resx 1 and *.cfg pass obviously optimizes away anything after the noreturn call: <bb 2>: __builtin_va_start (&args, 0); b (s, &args); <L5>: return; <L3>: finally_tmp.0 = 0; args = {CLOBBER}; switch (finally_tmp.0) <default: <L4>, case 1: <L5>> <L4>: resx 1 but the warn_function_return pass is immediately after that (and, this is -O0 anyway), so nothing optimizes the switch away into simple fall through into the resx 1 block. At -O and above we don't warn, because the *.eh pass before *.cfg pass optimizes this. So, IMHO to fix this, we need to do 2 things: 1) in decide_copy_try_finally reconsider if (!optimize) return ndests == 1; if finally contains only gimple_clobber_p stmts 2) estimate_num_insns should return 0 for gimple_clobber_p stmts
next prev parent reply other threads:[~2011-12-21 9:52 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-12-20 21:36 [Bug c/51644] New: " jan.kratochvil at redhat dot com 2011-12-21 9:18 ` [Bug c/51644] " burnus at gcc dot gnu.org 2011-12-21 9:52 ` [Bug middle-end/51644] " rguenth at gcc dot gnu.org 2011-12-21 9:53 ` jakub at gcc dot gnu.org [this message] 2011-12-21 9:54 ` jakub at gcc dot gnu.org 2011-12-21 11:41 ` jakub at gcc dot gnu.org 2011-12-21 15:00 ` jakub at gcc dot gnu.org 2011-12-21 15:33 ` jakub at gcc dot gnu.org 2011-12-21 15:33 ` jakub at gcc dot gnu.org
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