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Date: Fri, 15 Apr 2005 11:31:00 -0000
From: "aph at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: java-prs@gcc.gnu.org
Message-ID: <20050415113100.21044.aph@gcc.gnu.org>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug java/21044] New: Static class init optimization is broken
X-Bugzilla-Reason: CC
X-SW-Source: 2005-q2/txt/msg00129.txt.bz2
List-Id: <java-prs.sourceware.org>

Pre tree-SSA, we did an optimization whereby we only initialized a class once
per method invocation.  This optimization was disabled for some reason, and we
now call _Jv_InitClass multiple times.

The worst case is a simple function like this:

     public static int Ack(int m, int n) {
         return (m == 0) ? (n + 1) : ((n == 0) ? Ack(m-1, 1) :
                                      Ack(m-1, Ack(m, n - 1)));
     }

where Jv_InitClass is now called four times, leading to very poor performance.

-- 
           Summary: Static class init optimization is broken
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: java
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: aph 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=21044