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From: "zsojka at seznam dot cz" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/47316] New: devirtualize calls to virtual methods that are never further overriden Date: Sun, 16 Jan 2011 15:26:00 -0000 [thread overview] Message-ID: <bug-47316-4@http.gcc.gnu.org/bugzilla/> (raw) http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47316 Summary: devirtualize calls to virtual methods that are never further overriden Product: gcc Version: 4.6.0 Status: UNCONFIRMED Severity: enhancement Priority: P3 Component: tree-optimization AssignedTo: unassigned@gcc.gnu.org ReportedBy: zsojka@seznam.cz CC: jamborm@gcc.gnu.org Created attachment 22984 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22984 testcase Similiar to PR46043, but the compiler itself can be able to find out there are cases a virtual method is never overriden. Maybe this is the original intention of the devirtualization work, but in the case it is not, I am opening this PR. It is quite common to have one base class and several derived classes that are no further derived, and the hierarchy looks roughly like: class Base { virtual void f1(); virtual void f2(); virtual void f3(); }; class A : Base { virtual void f1() { ... this->f3(); ... } virtual void f2() { ... this->f1(); ... } }; class B : Base { virtual void f2() { ... this->f1(); ... } }; void foo(A *a) { ... a->f1(); ... } In a whole-program mode, if the compiler finds no type/variable is coming from external calls (where there could be possibly type derived from Base/A/B), all these cases could be devirtualized. Attached is a simple testcase that could be devirtualized, but isn't even with: $ g++ tstdevirt.C -O3 -fwhole-program
next reply other threads:[~2011-01-16 15:15 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2011-01-16 15:26 zsojka at seznam dot cz [this message] 2011-01-17 8:02 ` [Bug tree-optimization/47316] " zsojka at seznam dot cz 2011-01-17 12:35 ` redi at gcc dot gnu.org 2011-01-17 12:39 ` jamborm at gcc dot gnu.org 2013-12-17 16:22 ` hubicka at gcc dot gnu.org 2013-12-17 16:25 ` hubicka at gcc dot gnu.org
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