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From: "tromey at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug java/15525] New: suggestion to enable cast elimination Date: Wed, 19 May 2004 13:01:00 -0000 [thread overview] Message-ID: <20040518204228.15525.tromey@gcc.gnu.org> (raw) Diego pointed out on irc today that we could eliminate some casts by changing the java gimplifier a bit to allow CCP to do the work for us. Eg, consider this idiom: if (! (x instanceof foo)) return false; foo self = (foo) x; We could generate code like so: int tmp_1 = 0; if (! (_Jv_IsInstanceOf (x, &foo.class)) return 0; else tmp_1 = 1; foo self = tmp_1 ? (foo) x : _Jv_CheckCast (x, &foo.class); We could do this when generating code for "instanceof" along these lines: _Jv_IsInstanceOf(...) ? ({ tmp_1 = 1; 1 }) : 0 With this approach, redundant calls to _Jv_CheckCast would be automatically eliminated. Perhaps then we could have an extra pass to get rid of any remaining temporary variables that we introduced. -- Summary: suggestion to enable cast elimination Product: gcc Version: unknown Status: UNCONFIRMED Severity: enhancement Priority: P2 Component: java AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: tromey at gcc dot gnu dot org CC: gcc-bugs at gcc dot gnu dot org,java-prs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15525
next reply other threads:[~2004-05-18 20:42 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-05-19 13:01 tromey at gcc dot gnu dot org [this message] 2004-05-19 13:08 ` [Bug java/15525] " pinskia at gcc dot gnu dot org 2004-05-21 19:29 ` dnovillo at gcc dot gnu dot org 2004-08-27 20:55 ` tromey at gcc dot gnu dot org 2004-09-02 1:39 ` tromey at gcc dot gnu dot org 2005-03-09 4:38 ` pinskia at gcc dot gnu dot org 2005-05-01 0:57 ` tromey at gcc dot gnu dot org
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