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From: "rguenth at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/39799] [4.3/4.4/4.5 Regression] missing 'may be used uninitialized' warning Date: Fri, 17 Apr 2009 20:56:00 -0000 [thread overview] Message-ID: <20090417205552.7870.qmail@sourceware.org> (raw) In-Reply-To: <bug-39799-17592@http.gcc.gnu.org/bugzilla/> ------- Comment #1 from rguenth at gcc dot gnu dot org 2009-04-17 20:55 ------- This is because we zero-initialize uninitialized variables during inlining. Honza, do you remember why we do this? /* By inlining function having uninitialized variable, we might extend the lifetime (variable might get reused). This cause ICE in the case we end up extending lifetime of SSA name across abnormal edge, but also increase register pressure. We simply initialize all uninitialized vars by 0 except for case we are inlining to very first BB. We can avoid this for all BBs that are not inside strongly connected regions of the CFG, but this is expensive to test. */ -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |hubicka at gcc dot gnu dot | |org Status|UNCONFIRMED |NEW Component|regression |tree-optimization Ever Confirmed|0 |1 Keywords| |diagnostic Last reconfirmed|0000-00-00 00:00:00 |2009-04-17 20:55:52 date| | Summary|missing 'may be used |[4.3/4.4/4.5 Regression] |uninitialized' warning |missing 'may be used | |uninitialized' warning Target Milestone|--- |4.3.4 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39799
next prev parent reply other threads:[~2009-04-17 20:56 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-04-17 17:55 [Bug regression/39799] New: " alexvod at google dot com 2009-04-17 20:56 ` rguenth at gcc dot gnu dot org [this message] 2009-04-20 7:39 ` [Bug tree-optimization/39799] [4.3/4.4/4.5 Regression] " jakub at gcc dot gnu dot org 2009-04-20 9:32 ` rguenth at gcc dot gnu dot org 2009-04-22 13:37 ` rguenth at gcc dot gnu dot org 2009-08-04 12:48 ` rguenth at gcc dot gnu dot org 2010-05-22 18:32 ` [Bug tree-optimization/39799] [4.3/4.4/4.5/4.6 " rguenth at gcc dot gnu dot org 2010-06-30 14:17 ` bernds at gcc dot gnu dot org 2010-06-30 23:36 ` matt at use dot net 2010-07-01 17:14 ` danglin at gcc dot gnu dot org
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