Release Notes: Type Based Alias Analysis is now implemented and turned on by default in Clang. Inline assembly now supports multiple alternative constraints. LLVM IR now supports the unnamed_addr attribute to indicate that constant global variables with identical initializers can be merged. Link Time Optimization has been improved to use MC for parsing inline assembly. The new TargetLibraryInfo interface allows mid-level optimizations to know whether the current target's runtime library has certain functions. LLVM has a new RegionPass infrastructure for region-based optimizations.
Release Notes: Clang C++ is now feature-complete with respect to the ISO C++ 1998 and 2003 standards. Support for Objective-C++ was added. Many new warnings were introduced and format string checking was greatly improved. A C interface was introduced to Clang, intended to support IDE clients. Support for SSE, ARM NEON, and Altivec was added. Support for many Microsoft extensions was improved. Support for blocks and precompiled headers in C++ was implemented. Abstract syntax trees were improved to retain more accurate source information. There were numerous other enhancements and bugfixes.