LLVM 1.2 Release Notes

This document contains the release notes for the LLVM compiler -infrastructure, release 1.2. Here we describe the status of LLVM, including any +infrastructure, release 1.3. Here we describe the status of LLVM, including any known problems and bug fixes from the previous release. The most up-to-date version of this document can be found on the LLVM 1.2 web site. If you are +href="http://llvm.cs.uiuc.edu/releases/1.3/">LLVM 1.3 web site. If you are not reading this on the LLVM web pages, you should probably go there because this document may be updated after the release.

@@ -71,14 +70,7 @@ href="http://llvm.cs.uiuc.edu/releases/">releases page.

-This is the third public release of the LLVM compiler infrastructure. This -release incorporates several new features (including -exception handling support for the native code generators, the start of a -source-level debugger, and profile guided optimizer components), many speedups and code quality -improvements, documentation improvements, and a small collection of important bug fixes. Overall, this is our highest quality release to -date, and we encourage you to upgrade if you are using LLVM 1.0 or 1.1. +This is the fourth public release of the LLVM compiler infrastructure.

@@ -95,45 +87,8 @@ the C front-end.

A new LLVM source-level debugger has been started.
LLVM 1.2 encodes bytecode files for large programs in 10-30% less space.
LLVM can now feed profile information back into optimizers for Profile Guided Optimization, includes a simple basic block reordering pass, and supports edge profiling as well as function and block-level profiling.
The LLVM JIT lazily initializes global variables, reducing startup time for programs with lots of globals (like C++ programs).
The build and installation infrastructure in this release is dramatically -improved. There is now an autoconf/AutoRegen.sh script -that you can run to rebuild the configure script and its associated -files as well as beta support for "make install" and RPM package generation.
The "tblgen" tool is now documented.
The target-independent code generator got several improvements: -
- It can now fold spill code into instructions (on targets that support it).
- A generic machine code spiller/rewriter was added. It provides an API for - global register allocators to eliminate virtual registers and add the - appropriate spill code.
- The represenation of machine code basic blocks is more efficient and has - an easier to use interface.
-
LLVM now no longer depends on the boost library.
The X86 backend now generates substantially better native code and is faster.
The C backend has been turned moved from the "llvm-dis" tool to the "llc" -tool. You can activate it with "llc -march=c foo.bc -o foo.c".
LLVM includes a new interprocedural optimization that marks global variables -"constant" when they are provably never written to.
LLVM now includes a new interprocedural optimization that converts small "by reference" arguments to "by value" arguments, which often improves the performance of C++ programs substantially.
Bugpoint can now do a better job reducing miscompilation problems by -reducing programs down to a particular loop nest, instead of just the function -being miscompiled.
The GCSE and LICM passes can now operate on side-effect-free function calls, for example hoisting calls to "strlen" and folding "cos" common subexpressions.
LLVM has early support for a new select instruction, though it is -currently only supported by the C backend.
The LLVM select instruction is +now fully implemented and supported by all targets.

@@ -143,13 +98,7 @@ In this release, the following missing features were implemented: