LLVM 3.3 Released!

LLVM 3.3 is now available! For details, you can read the Release Notes.

LLVM 3.3 is a big release: it adds new targets for the AArch64 and AMD R600 GPU architectures, adds support for IBM's z/Architecture S390 systems, and major enhancements for the PowerPC backend (including support for PowerPC 2.04/2.05/2.06 instructions, and an integrated assembler) and MIPS targets.

Performance of code generated by LLVM 3.3 is substantially improved: the auto-vectorizer produces much better code in many cases and is on by default at -O3, a new SLP vectorizer is available, and many general improvements landed in this release. Independent evaluations show that LLVM 3.3's performance exceeds that of LLVM 3.2 and of its primary competition on many benchmarks.

3.3 is also a major milestone for the Clang frontend: it is now fully C++'11 feature complete. At this point, Clang is the only compiler to support the full C++'11 standard, including important C++'11 library features like std::regex. Clang now supports Unicode characters in identifiers, the Clang Static Analyzer supports several new checkers and can perform interprocedural analysis across C++ constructor/destructor boundaries, and Clang even has a nice "C++'11 Migrator" tool to help upgrade code to use C++'11 features and a "Clang Format" tool that plugs into vim and emacs (among others) to auto-format your code.

LLVM 3.3 is the result of an incredible number of people working together over the last six months, but this release would not be possible without our volunteer release team! Thanks to Bill Wendling for shepherding the release, and to Ben Pope, Dimitry Andric, Nikola Smiljanic, Renato Golin, Duncan Sands, Arnaud A. de Grandmaison, Sebastian Dreßler, Sylvestre Ledru, Pawel Worach, Tom Stellard, Kevin Kim, and Erik Verbruggen for all of their contributions pulling the release together.

If you have questions or comments about this release, please contact the LLVMdev mailing list! Onward to LLVM 3.4!

LLVM 3.3 Vectorization Improvements

I would like to give a brief update regarding vectorization in LLVM. When LLVM 3.2 was released, it featured a new experimental loop vectorizer that was disabled by default. Since LLVM 3.2 was released, we have continued to work hard on improving vectorization, and we have some news to share. First, the loop vectorizer has new features and is now enabled by default on -O3. Second, we have a new SLP vectorizer. And finally, we have new clang command line flags to control the vectorizers.

EuroLLVM 2013, Paris, France

Two days after the end of EuroLLVM 2013, I finally got the energy to write a piece about it. It was a lot of hard work by an amazing team of volunteer organizers lead by Tobias Grosser, Duncan Sands, Sylvestre Ledru and Arnaud de Grandmaison, plus the usual suspects of the previous events, and in the end there was very little that had gone wrong, even in the slightest.


This was our biggest event yet, with 187 attendees, 12 talks, 2 tutorials, 7 lightning talks and 10 posters! The posters, slides and videos are available on the EuroLLVM 2013 website, as well as some idea on the abstracts, location (ENS, in Paris) and the great dinner cruise on Monday.

You can also find on the site the results of our questionnaire, distilled and anonymized.

Clang support for C++11 and beyond

As of r179861, Clang implements the entirety of the C++11 language standard. The following features have been implemented since the release of Clang 3.2, along with our plans for "C++1y".

Euro LLVM 2013 in Paris

In two weeks, the 2013 edition of the Euro LLVM conference will start in historic center of Paris, France.  The schedule has just been published.  Most of different aspects of the LLVM infrastructure will present at the event.  See below for the full details!

Status of the C++11 Migrator

Since the design document for cpp11-migrate, the C++11 migrator tool, was first proposed in early December 2012 development has been making steady progress. In this article I'll talk about what's been implemented in cpp11-migrate so far, what's coming up, and how you can get involved.

The purpose of the C++11 Migrator is to do source-to-source translation to migrate existing C++ code to use C++11 features to enhance maintainability, readability, runtime performance, and compile-time performance. Development is still early and transforms fall mostly into the first two categories. The migrator is based on Clang's LibTooling and the AST Matching library.

Most of the development so far has been carried out by a small core group at Intel. Our focus so far has been to set up project infrastructure and testing, implement a few basic transforms, and make sure those transforms work well. Our aim is to make this tool useful to the community so we're always listening for transform ideas and feedback.

Static analysis tools: using Clang in CppDepend

Static analysis is a method of computer program debugging that is done by examining the code without executing the program. The process provides an understanding of the code structure, can help to ensure that the code adheres to industry standards, and can find bugs not easy to detect.

To develop a C / C++ static analysis tool, a parser is needed to parse the source code. C++ is a very powerful language but its syntax is a little bit complicated, what makes the parser not easy to develop.

When we began the development of CppDepend about four years ago we needed a reliable C / C++ parser.  At that time, Clang was an option but was not widely used and we didn’t know if it would ultimately develop into a fully-featured compiler frontend.

Last year, for the major release of CppDepend 3.0, we re-evaluated our C / C++ parser with a goal of getting more reliable results.  We checked Clang to see where its evolution went and were very surprised that it now implements virtually all C++'11 features and became very popular.  Clang now provide solid infrastructure to write tools that need syntactic and semantic information about a program.