similar to: [LLVMdev] Call to address 0 gets removed

There's another point that hasn't been raised yet here, which is that the undefinedness of calling (void*) 0 is a property of C, not necessarily of the LLVM abstract language. I think you can make an excellent case that the standard optimizations should not be enforcing C language semantics, or at least should allow such optimizations to be disabled. Case in point —

2009/6/10 John McCall <rjmccall at apple.com> > There's another point that hasn't been raised yet here, which is that > the > undefinedness of calling (void*) 0 is a property of C, not necessarily > of > the LLVM abstract language. I think you can make an excellent case that > the standard optimizations should not be enforcing C language semantics, > or at

On Jun 9, 2009, at 10:02 AMPDT, Paul Schlie wrote: >> Dale Johannesen wrote: >>> Marius Wachtler wrote: >>> ... >>> The call to address 0 gets removed. >>> >>> define i32 @t(i32 %a) noreturn nounwind readnone { >>> entry: >>> unreachable >>> } >>> >>> How can I prevent that the call is removed,

On Jun 10, 2009, at 1:18 PM, Nick Lewycky wrote: > 2009/6/10 John McCall <rjmccall at apple.com> > There's another point that hasn't been raised yet here, which is that > the > undefinedness of calling (void*) 0 is a property of C, not necessarily > of > the LLVM abstract language. I think you can make an excellent case > that > the standard optimizations

Edwin was asking about how we should handle PR3328, how we should make GEP respect -fwrapv etc. I wrote up some thoughts here if anyone is interested: http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt -Chris

> Dale Johannesen wrote: >> Marius Wachtler wrote: >> ... >> The call to address 0 gets removed. >> >> define i32 @t(i32 %a) noreturn nounwind readnone { >> entry: >> unreachable >> } >> >> How can I prevent that the call is removed, without making the >> function addr volatile? >> Does anyone know which optimization

On Jun 16, 2009, at 7:34 AM, Aaron Gray wrote: >> The LLVM IR opcodes Add, Sub, and Mul have been each split into >> two. Add, Sub, and Mul now only handle integer types, and three >> new opcodes, FAdd, FSub, and FMul now handle floating-point types. > > Dan, > > Wondering the reason why there is no FDiv ? FDiv already exists; div was split quite a while ago. Dan

----- Original Message ----- From: "Dan Gohman" <gohman at apple.com> To: "LLVM Developers Mailing List" <llvmdev at cs.uiuc.edu> Sent: Tuesday, June 16, 2009 7:49 AM Subject: Re: [LLVMdev] Upcoming API change: FAdd, FSub, FMul > > On Jun 16, 2009, at 7:34 AM, Aaron Gray wrote: > >>> The LLVM IR opcodes Add, Sub, and Mul have been each split

Not sure if this the right place, but I can't seem to subscribe to the rJava mailing list. Sorry for the noise. I have a jar file in the CLASSPATH variable. On running .jinit and checking .jclassPath, i can see the jar file containing the class. Yet when trying to instantaite the class, i get a class not found error. Now If if, create my own vm (see below), and then run .jinit (which will

Hi, I need the description of LLVM instructions on bitcode file. I can't find it on any document. Reading the code costs much time. Does a description like this exist ? It should look like the JVM Instruction set on the link bellow: http://java.sun.com/docs/books/jvms/second_edition/html/Instructions2.doc.ht ml Thanks for any advise. Quang

Dear developers, Are there any benchmarks for the performance of Java Native Interface (JNI) calls in VMKit? Since VMKit is based on LLVM which can also run C++ code (maybe in the same just-in-time compiler?) I guess calls from Java to C++ and back could be much faster than in Sun's JVM which has extremely slow C++ -> Java callbacks. If this was the case, this would be a big advantage of

Duncan Sands wrote: >> One approach would be to simply duplicate the code in the 'finally' >> block for each exit, but that seems sub-optimal. It would be better, I >> think, to set a state variable before entering the 'finally' block, and >> then have it do a switch instruction at the end and transfer to the >> appropriate block. >>

Hi there, I am trying to diagnose a performance problem on a Sun T5120 running Solaris 10. I see general poor performance using Java and, in particular, loading classes. I have developed a simple java test that loads all of the classes in a Crystal Reports JAR file (around 7000 classes) which takes much longer on the T5120 (40 secs) than on a Core 2 Duo windows PC (5 secs). I recognise that this

Has anyone attempted to run Rails inside of JRuby? Is that even possible? Aside from the performance implications, is it a bad idea? I''m thinking that it might be useful in very rare cases where a Ruby/Rails - equivalent of a Java solution may not exist yet. Any thoughts? Wes -- Posted via http://www.ruby-forum.com/.

In our environment we have many legacy application servers running apache/jserv. There is a web server front end, then a couple of load-balanced java servers on the backside. One of the problems we are faced with is hung or stuck jvms. I have looked at the java process with the ps command, and there are many times when URL(s) do not respond, yet the java looks healthy, at least from the OS

Hi Bruno, On Wed, Jun 20, 2012 at 3:04 PM, Bruno Daniel <abml at mailoo.org> wrote: > Dear developers, > > Are there any benchmarks for the performance of Java Native Interface (JNI) > calls in VMKit? Since VMKit is based on LLVM which can also run C++ code > (maybe in the same just-in-time compiler?) I guess calls from Java to C++ > and > back could be much faster

A few random observations: 1. Clang could do better with large but boring switches like this: http://embed.cs.utah.edu/embarrassing/jan_10/harvest/source/E8/E88C5111.shtml Performance of clang's output will be fine but this is a major code size lose. 2. Destruction of stupid loops is incomplete, sometimes due to phase ordering problems:

On Tue, 18 Apr 2006, Tom Tromey wrote: >>>>>> "Chris" == Chris Lattner <sabre at nondot.org> writes: >>> FWIW I actually did this work twice, once for libjit and once for >>> LLVM. I'm happy to provide a comparison, from a jit-writing >>> perspective, if you're interested. > > Chris> Given your experience with both,

Hi Nicolas, thanks for your detailed answer! Now I understand the issues a little better. I'm going to install LLVM + Vmkit and try it out using JNI. Regarding the garbage collector, do you think that the Garbage Collection ABI of C++11 could be implemented in a way compatible to the JVM's garbage collector? http://www2.research.att.com/~bs/C++0xFAQ.html#gc-abi Perhaps this could make

On 6/3/2011 3:19 PM, Samuel Crow wrote: > Why not runtime checks? The constant folding and dead-code elimination passes would get rid of any redundant code in a later stage of compilation anyway. The important part, as I see it, is that LLVM already does constant folding and dead-code elimination. Meta-data might require more effort in the long run. > > --snip-- Less flexible for the