From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Berlin To: Gerald Pfeifer Cc: Joe Buck , Mark Mitchell , "gcc@gcc.gnu.org" Subject: Re: C++ compile-time regressions (was: GCC 3.0.1 Status Report) Date: Tue, 24 Jul 2001 07:55:00 -0000 Message-id: <87r8v6gywb.fsf@cgsoftware.com> References: X-SW-Source: 2001-07/msg01568.html Gerald Pfeifer writes: > On Mon, 23 Jul 2001, Joe Buck wrote: >> Can you try to isolate where the bad code is? > > Not really. This code base is relatively large and the inner loops > are quite complicated (actually not really loops as you'd see in usual > scientific computing code) amounting to several thousand lines of code, > and my day job is very time demanding these days, so I'm afraid I simply > won't have the time anytime soon. > > I'm rather sure, though, that g++ is not generating efficient code for > complicated, nested STL and STL-like structures in the presence of > libstdc++-v3 (iterators are now classes instead of pointers). This is probably alias analysis's fault. Can you *try* the patch i posted to do alias analysis for classes, just to see if it gets better code (Unless mark is wrong, and its not more complicated than i thought it was, and i seriously doubt he's wrong, it might generate invalid code)? I could also do some more analysis if you could make that particular test available to me. --Dan -- "I got into an elevator at work and this man followed in after me... I pushed "1" and he just stood there... I said, "Hi, where you going?" He said, "Phoenix." So I pushed Phoenix. A few seconds later the doors opened, two tumbleweeds blew in... We were in downtown Phoenix. I looked at him and said, "You know, you're the kind of guy I want to hang around with." We got into his car and drove out to his shack in the desert. Then the phone rang. He said, "You get it." I picked it up and said, "Hello?"... The other side said, "Is this Steven Wright?"... I said, "Yes..." The guy said, "Hi, I'm Mr. Jones, the student loan director from your bank. It seems you have missed your last 17 payments, and the university you attended said that they received none of the $17,000 we loaned you. We would just like to know what happened to the money?" I said, "Mr. Jones, I'll give it to you straight. I gave all of the money to my friend Slick, and with it he built a nuclear weapon... And I would appreciate it if you never called me again." "-Steven Wright