9 These are in-progress notes for the upcoming LLVM 3.4 release. You may
10 prefer the `LLVM 3.3 Release Notes <http://llvm.org/releases/3.3/docs
11 /ReleaseNotes.html>`_.
17 This document contains the release notes for the LLVM Compiler Infrastructure,
18 release 3.4. Here we describe the status of LLVM, including major improvements
19 from the previous release, improvements in various subprojects of LLVM, and
20 some of the current users of the code. All LLVM releases may be downloaded
21 from the `LLVM releases web site <http://llvm.org/releases/>`_.
23 For more information about LLVM, including information about the latest
24 release, please check out the `main LLVM web site <http://llvm.org/>`_. If you
25 have questions or comments, the `LLVM Developer's Mailing List
26 <http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev>`_ is a good place to send
29 Note that if you are reading this file from a Subversion checkout or the main
30 LLVM web page, this document applies to the *next* release, not the current
31 one. To see the release notes for a specific release, please see the `releases
32 page <http://llvm.org/releases/>`_.
34 Non-comprehensive list of changes in this release
35 =================================================
38 For small 1-3 sentence descriptions, just add an entry at the end of
39 this list. If your description won't fit comfortably in one bullet
40 point (e.g. maybe you would like to give an example of the
41 functionality, or simply have a lot to talk about), see the `NOTE` below
42 for adding a new subsection.
44 * This is expected to be the last release of LLVM which compiles using a C++98
45 toolchain. We expect to start using some C++11 features in LLVM and other
46 sub-projects starting after this release. That said, we are committed to
47 supporting a reasonable set of modern C++ toolchains as the host compiler on
48 all of the platforms. This will at least include Visual Studio 2012 on
49 Windows, and Clang 3.1 or GCC 4.7.x on Mac and Linux. The final set of
50 compilers (and the C++11 features they support) is not set in stone, but we
51 wanted users of LLVM to have a heads up that the next release will involve
52 a substantial change in the host toolchain requirements.
54 * The regression tests now fail if any command in a pipe fails. To disable it in
55 a directory, just add ``config.pipefail = False`` to its ``lit.local.cfg``.
56 See :doc:`Lit <CommandGuide/lit>` for the details.
58 * Support for exception handling has been removed from the old JIT. Use MCJIT
59 if you need EH support.
61 * The R600 backend is not marked experimental anymore and is built by default.
63 * APFloat::isNormal() was renamed to APFloat::isFiniteNonZero() and
64 APFloat::isIEEENormal() was renamed to APFloat::isNormal(). This ensures that
65 APFloat::isNormal() conforms to IEEE-754R-2008.
67 * The library call simplification pass has been removed. Its functionality
68 has been integrated into the instruction combiner and function attribute
71 * Support for building using Visual Studio 2008 has been dropped. Use VS 2010
72 or later instead. For more information, see the `Getting Started using Visual
73 Studio <GettingStartedVS.html>`_ page.
75 * The Loop Vectorizer that was previously enabled for -O3 is now enabled for
78 * The new SLP Vectorizer is now enabled by default.
80 * llvm-ar now uses the new Object library and produces archives and
81 symbol tables in the gnu format.
83 * FileCheck now allows specifing -check-prefix multiple times. This
84 helps reduce duplicate check lines when using multiple RUN lines.
86 * The bitcast instruction no longer allows casting between pointers
87 with different address spaces. To achieve this, use the new
88 addrspacecast instruction.
90 * Different sized pointers for different address spaces should now
91 generally work. This is primarily useful for GPU targets.
96 If you would like to document a larger change, then you can add a
97 subsection about it right here. You can copy the following boilerplate
98 and un-indent it (the indentation causes it to be inside this comment).
103 Makes programs 10x faster by doing Special New Thing.
108 Support for the MIPS SIMD Architecture (MSA) has been added. MSA is supported
109 through inline assembly, intrinsics with the prefix '__builtin_msa', and normal
112 For more information on MSA (including documentation for the instruction set),
113 see the `MIPS SIMD page at Imagination Technologies
114 <http://imgtec.com/mips/mips-simd.asp>`_
116 External Open Source Projects Using LLVM 3.4
117 ============================================
119 An exciting aspect of LLVM is that it is used as an enabling technology for
120 a lot of other language and tools projects. This section lists some of the
121 projects that have already been updated to work with LLVM 3.4.
124 LDC - the LLVM-based D compiler
125 -------------------------------
127 `D <http://dlang.org>`_ is a language with C-like syntax and static typing. It
128 pragmatically combines efficiency, control, and modeling power, with safety and
129 programmer productivity. D supports powerful concepts like Compile-Time Function
130 Execution (CTFE) and Template Meta-Programming, provides an innovative approach
131 to concurrency and offers many classical paradigms.
133 `LDC <http://wiki.dlang.org/LDC>`_ uses the frontend from the reference compiler
134 combined with LLVM as backend to produce efficient native code. LDC targets
135 x86/x86_64 systems like Linux, OS X, FreeBSD and Windows and also Linux/PPC64.
136 Ports to other architectures like ARM and AArch64 are underway.
139 Additional Information
140 ======================
142 A wide variety of additional information is available on the `LLVM web page
143 <http://llvm.org/>`_, in particular in the `documentation
144 <http://llvm.org/docs/>`_ section. The web page also contains versions of the
145 API documentation which is up-to-date with the Subversion version of the source
146 code. You can access versions of these documents specific to this release by
147 going into the ``llvm/docs/`` directory in the LLVM tree.
149 If you have any questions or comments about LLVM, please feel free to contact
150 us via the `mailing lists <http://llvm.org/docs/#maillist>`_.