"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
+ <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<link rel="stylesheet" href="llvm.css" type="text/css">
- <title>LLVM 1.3 Release Notes</title>
+ <title>LLVM 1.6 Release Notes</title>
</head>
<body>
-<div class="doc_title">LLVM 1.3 Release Notes</div>
+<div class="doc_title">LLVM 1.6 Release Notes</div>
<ol>
<li><a href="#intro">Introduction</a></li>
<li><a href="GettingStarted.html">Installation Instructions</a></li>
<li><a href="#portability">Portability and Supported Platforms</a></li>
<li><a href="#knownproblems">Known Problems</a>
- <ul>
- <li><a href="#experimental">Experimental features included in this
- release</a>
- <li><a href="#core">Known problems with the LLVM Core</a>
- <li><a href="#c-fe">Known problems with the C Front-end</a>
- <li><a href="#c++-fe">Known problems with the C++ Front-end</a>
- <li><a href="#x86-be">Known problems with the X86 Back-end</a>
- <li><a href="#sparc-be">Known problems with the Sparc Back-end</a>
- <li><a href="#c-be">Known problems with the C back-end</a>
- </ul></li>
<li><a href="#additionalinfo">Additional Information</a></li>
</ol>
-<div class="doc_text">
- <p>
<b>Written by the <a href="http://llvm.cs.uiuc.edu">LLVM team</a></b><p>
+<div class="doc_author">
+ <p>
Written by the <a href="http://llvm.org">LLVM Team</a><p>
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<p>This document contains the release notes for the LLVM compiler
-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 <a
-href="http://llvm.cs.uiuc.edu/releases/1.3/">LLVM 1.3 web site</a>. If you are
+infrastructure, release 1.6. Here we describe the status of LLVM, including any
+known problems and major improvements from the previous release. The most
+
up-to-date version of this document can be found on the <a
+href="http://llvm.org/releases/1.6/">LLVM 1.6 web site</a>. 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.</p>
-<p>For more information about LLVM, including information about potentially more
-current releases, please check out the <a href="http://llvm.cs.uiuc.edu">main
+<p>For more information about LLVM, including information about the latest
+release, please check out the <a href="http://llvm.org/">main LLVM
web site</a>. If you have questions or comments, the <a
href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">LLVM developer's mailing
list</a> is a good place to send them.</p>
-<p>Note that if you are reading this file from CVS, this document applies
-to the <i>next</i> release, not the current one. To see the release notes for
-the current or previous releases, see the <a
-href="http://llvm.cs.uiuc.edu/releases/">releases page</a>.</p>
+<p>Note that if you are reading this file from CVS or the main LLVM web page,
+this document applies to the <i>next</i> release, not the current one. To see
+the
release notes for the current or previous releases, see the <a
+href="http://llvm.org/releases/">releases page</a>.</p>
</div>
<div class="doc_text">
-<p>
-This is the fourth public release of the LLVM compiler infrastructure. This
-release primarily improves the <a href="#codequality">performance of the
-code</a> produced by all aspects of the LLVM compiler and adds some <a
-href="#newfeatures">new features</a>, though it does <a href="#bugfix">fix a few
-bugs</a> as well.
-</p>
-
-<p>
-At this time, LLVM is known to correctly compile and run all C & C++ SPEC
-CPU2000 benchmarks, the Olden benchmarks, and the Ptrdist benchmarks. It has
-also been used to compile <b>many</b> other programs. LLVM now also works with
-a broad variety of C++ programs, though it has still received less testing than
-the C front-end.
-</p>
+<p>This is the seventh public release of the LLVM Compiler Infrastructure. This
+release incorporates a large number of enhancements and additions (primarily in
+the code generator), which combine to improve the quality of the code generated
+by LLVM by up to 30% in some cases. This release is also the first release to
+have first-class support for Mac OS X: all of the major bugs have been shaken
+out and it is now as well supported as Linux on X86.</p>
+
+</div>
<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="newfeatures">This release implements the following new features:</a>
+<div class="doc_subsection">
+<a name="newfeatures">New Features in LLVM 1.6</a>
</div>
-<ol>
-<li>The LLVM <a href="LangRef.html#i_select"><tt>select</tt></a> instruction is
-now fully implemented and supported by all transformations, native code
-generators, and the interpreter.</li>
-<li>Bugpoint can now narrow down code-generation bugs to a loop nest, where
-before it could only narrow them down to a function being miscompiled.</li>
-<li><a href="http://llvm.cs.uiuc.edu/PR40">Bugpoint can now debug arbitrary
-modes of llc</a> and lli, by passing them command line flags (e.g.,
-<tt>-regalloc=linearscan</tt>, <tt>-enable-correct-eh-support</tt>, etc.) </li>
-<li>The Control Flow Graph in the native code generators is no longer
-constrained to be the same as the CFG for the LLVM input code.</li>
-<li>The LLVM induction variable analysis routines have been rewritten.</li>
-<li>LLVM now has new loop unrolling and loop unswitching passes.</li>
-<li>The induction variable substitution pass performs linear function test
-replacement and exit value replacement optimizations.</li>
-</ol>
+<!--_________________________________________________________________________-->
+<div class="doc_subsubsection"><a name="iselgen">Instruction Selector
+Generation from Target Description</a></div>
+<div class="doc_text">
+<p>LLVM now includes support for auto-generating large portions of the
+instruction selectors from target descriptions. This allows us to
+write patterns in the target .td file, instead of writing lots of
+nasty C++ code. Most of the PowerPC instruction selector is now
+generated from the PowerPC target description files and other targets
+are adding support that will be live for LLVM 1.7.</p>
-<!--=========================================================================-->
-<div class="doc_subsubsection">
-In this release, the following missing features were implemented:
-</div>
+<p>For example, here are some patterns used by the PowerPC backend. A
+floating-point multiply then subtract instruction (FMSUBS):</p>
-<ol>
-<li><a href="http://llvm.cs.uiuc.edu/PR82">LLVM cannot handle structures with
-more than 256 elements</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR38">[bugpoint] External functions used in
-non-instruction entities, such as global constant initializer</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR290">Bugpoint doesn't support
-uses of external fns by immediate constant exprs</a></li>
-</ol>
+<div class="doc_code"><p>
+<tt>(set F4RC:$FRT, (fsub (fmul F4RC:$FRA, F4RC:$FRC), F4RC:$FRB))</tt>
+</p></div>
+<p>Exclusive-or by 16-bit immediate (XORI):</p>
-<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="qualityofimp">In this release, the following Quality of Implementation
-issues were fixed:</a>
-</div>
+<div class="doc_code"><p>
+<tt>(set GPRC:$dst, (xor GPRC:$src1, immZExt16:$src2))</tt>
+</p></div>
-<ol>
-<li><a href="http://llvm.cs.uiuc.edu/PR305">LLVM tools will happily spew
-bytecode onto your terminal</a></li>
-</ol>
+<p>Exclusive-or by 16-bit immediate shifted right 16-bits (XORIS):</p>
-<!--=========================================================================-->
-<div class="doc_subsubsection">
-In this release, the following build problems were fixed:
-</div>
+<div class="doc_code"><p>
+<tt>(set GPRC:$dst, (xor GPRC:$src1, imm16Shifted:$src2))</tt>
+</p></div>
-<ol>
-<li><a href="http://llvm.cs.uiuc.edu/PR301">Minor configure bugs with -disable/enable-povray and -disable-spec</a></li>
-</ol>
+<p>With these definitions, we teach the code generator how to combine these two
+instructions to xor an abitrary 32-bit immediate with the following
+definition. The first line specifies what to match (a xor with an arbitrary
+immediate) the second line specifies what to produce:</p>
+
+<div class="doc_code"><p>
+<pre>def : Pat<(xor GPRC:$in, imm:$imm),
+ (XORIS (XORI GPRC:$in, (LO16 imm:$imm)), (HI16 imm:$imm))>;
+</pre>
+</p></div>
-<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="codequality">This release includes the following Code Quality
-improvements:</a>
</div>
-<ol>
-<li>Fixed: <a href="http://llvm.cs.uiuc.edu/PR309">[vmcore] Code quality problem
-due to long operand of getelementptr</a></li>
+<!--_________________________________________________________________________-->
+<div class="doc_subsubsection"><a name="sched">Instruction Scheduling
+Support</a></div>
-<li>The X86 backend now generates substantially better code for 64-bit integer
-and floating point operations.</li>
+<div class="doc_text">
+
+<p>Instruction selectors using the refined <a
+href="CodeGenerator.html#instselect">instruction selection framework</a> can now
+use a simple pre-pass scheduler included with LLVM 1.6. This scheduler is
+currently simple (cannot be configured much by the targets), but will be
+extended in the future.</p>
+</div>
-<li>The -inline pass no longer inlines mutually recursive functions until it
-hits the inlining threshold.</li>
+<!--_________________________________________________________________________-->
+<div class="doc_subsubsection"><a name="subtarget">Code Generator Subtarget
+Support</a></div>
-<li>The -inline pass no longer misses obvious inlining opportunities just
-because the callee eventually calls into an external function.</li>
+<div class="doc_text">
+<p>It is now straight-forward to parameterize a target implementation, and
+provide a mapping from CPU names to sets of target parameters. LLC now supports
+a <tt>-mcpu=cpu</tt> option that lets you choose a subtarget by CPU name: use
+"<tt>llvm-as < /dev/null | llc -march=XXX -mcpu=help</tt>" to get a list of
+supported CPUs for target "XXX". It also provides a
+<tt>-mattr=+attr1,-attr2</tt> option that can be used to control individual
+features of a target (the previous command will list available features as
+well).</p>
-<li>The -simplifycfg pass can now "if convert" simple statements into the new
-<tt>select</tt> instruction.</li>
+<p>This functionality is nice when you want tell LLC something like "compile to
+code that is specialized for the PowerPC G5, but doesn't use altivec code. In
+this case, using "<tt>llc -march=ppc32 -mcpu=g5 -mattr=-altivec</tt>".</p>
-<li>The -loopsimplify pass can now break <a
-href="http://llvm.cs.uiuc.edu/PR35">natural loops with multiple backedges</a>
-into multiple nested loops. This enables a variety of subsequent
-optimizations.</li>
+</div>
-<li>The -adce pass can now eliminate calls to functions that do not not write to
-memory.</li>
+<!--_________________________________________________________________________-->
+<div class="doc_subsubsection"><a name="jitlock">Other New Features</a></div>
-<li>The link-time optimizer now runs the -prune-eh pass (to remove unused
-exception handlers).</li>
+<div class="doc_text">
+<ol>
+ <li>The JIT now uses mutexes to protect its internal data structures. This
+ allows multi-threaded programs to be run from the JIT or interpreter without
+ corruption of the internal data structures. See
+ <a href="http://llvm.org/PR418">PR418</a> and
+ <a href="http://llvm.org/PR540">PR540</a> for the details.
+ </li>
+ <li>LLVM on Win32 <a href="http://llvm.org/PR614">no longer requires sed,
+ flex, or bison when compiling with Visual C++</a>.</li>
+ <li>The llvm-test suite can now use the NAG Fortran to C compiler to compile
+ SPEC FP programs if available (allowing us to test all of SPEC'95 &
+ 2000).</li>
+ <li>When bugpoint is grinding away and the user hits ctrl-C, it now
+ gracefully stops and gives what it has reduced so far, instead of
+ giving up completely. In addition, <a href="http://llvm.org/PR576">the JIT
+ debugging mode of bugpoint is much faster</a>.</li>
+ <li>LLVM now includes Xcode project files in the llvm/Xcode directory.</li>
+ <li>LLVM now supports Mac OS X on Intel.</li>
+ <li>LLVM now builds cleanly with GCC 4.1.</li>
+</ol>
+</div>
-<li>The -simplifycfg pass can now eliminate simple correlated branches (such as
-"<tt>if (A < B && A < B)</tt>", and can turn short-circuiting
-operators into the strict versions when useful (such as "<tt>if (A < B || A
-> C)</tt>" into "<tt>if (A < B | A > C)</tt>"</li>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="codequality">Code Quality Improvements in LLVM 1.6</a>
+</div>
-<li>LLVM now has infrastructure for (simple and sparse conditional) constant
-propagation of function calls. It currently supports a few math library
-functions like sqrt/sin/cos/etc.</li>
+<div class="doc_text">
+<ol>
+ <li>The <tt>-globalopt</tt> pass can now statically evaluate C++ static
+ constructors when they are simple enough. For example, it can
+ now statically initialize "<tt>struct X { int a; X() : a(4) {} } g;</tt>".
+ </li>
+ <li>The Loop Strength Reduction pass has been completely rewritten, is far
+ more aggressive, and is turned on by default in the RISC targets. On PPC,
+ we find that it often speeds up programs from 10-40% depending on the
+ program.</li>
+ <li>The code produced when exception handling is enabled is far more
+ efficient in some cases, particularly on Mac OS X.</li>
</ol>
+</div>
<!--=========================================================================-->
-<div class="doc_subsubsection">
-<a name="bugfix">In this release, the following bugs in the previous release
-were fixed:</a>
+<div class="doc_subsection">
+<a name="codequality">Code Generator Improvements in LLVM 1.6</a>
</div>
-<p>Bugs in the LLVM Core:</p>
-
+<div class="doc_text">
<ol>
-<li><a href="http://llvm.cs.uiuc.edu/PR306">[loopsimplify] Loop simplify
-incorrectly updates dominator information</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR310">[tailduplicate] DemoteRegToStack
-breaks SSA form</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR313">[X86] JIT miscompiles unsigned short
-to floating point cast</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR332">[adce] Crash handling unreachable code that unwinds</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR333">[sparc] LLC can't emit 2 functions of
-the same name, both having constant pools</a></li>
+<li>The Alpha backend is substantially more stable and robust than in LLVM 1.5.
+ For example, it now fully supports varargs functions. The Alpha backend
+ also now features beta JIT support.</li>
+<li>The code generator contains a new component, the DAG Combiner. This allows
+ us to optimize lowered code (e.g. after 64-bit operations have been lowered
+ to use 32-bit registers on 32-bit targets) and do fine-grained bit-twiddling
+ optimizations for the backend.</li>
+<li>The SelectionDAG infrastructure is far more capable and mature, able to
+ handle many new target peculiarities in a target-independent way.</li>
+<li>The default <a href="http://llvm.org/PR547">register allocator is now far
+ faster on some testcases</a>,
+ particularly on targets with a large number of registers (e.g. IA64
+ and PPC).</li>
</ol>
+</div>
-<p>Bugs in the C/C++ front-end:</p>
+<!--=========================================================================-->
+<div class="doc_subsection">
+<a name="bugfix">Significant Bugs Fixed in LLVM 1.6</a>
+</div>
+<div class="doc_text">
<ol>
-<li><a href="http://llvm.cs.uiuc.edu/PR326">[llvmgcc] Crash on use of undeclared enum type</a></li></li>
+ <li>A vast number of bugs have been fixed in the PowerPC backend and in
+ llvm-gcc when configured for Mac OS X (particularly relating to ABI
+ issues). For example:
+ <a href="http://llvm.org/PR603">PR449</a>,
+ <a href="http://llvm.org/PR594">PR594</a>,
+ <a href="http://llvm.org/PR603">PR603</a>,
+ <a href="http://llvm.org/PR609">PR609</a>,
+ <a href="http://llvm.org/PR630">PR630</a>,
+ <a href="http://llvm.org/PR643">PR643</a>,
+ and several others without bugzilla bugs.</li>
+ <li>Several bugs in tail call support have been fixed.</li>
+ <li><a href="http://llvm.org/PR608">configure does not correctly detect gcc
+ version on cygwin</a>.</li>
+ <li>Many many other random bugs have been fixed. Query <a
+ href="http://llvm.org/bugs">our bugzilla</a> with a target of 1.6 for more
+ information.</li>
</ol>
-
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
-<p>LLVM has been extensively tested on Intel and AMD machines running Red
-Hat Linux and FreeBSD. It has also been tested on Sun UltraSPARC workstations
-running Solaris 8. Additionally, LLVM works on Mac OS X 10.3 and above, but
-only with the C backend or interpreter (no native backend for the PowerPC is
-available yet). The core LLVM infrastructure uses "autoconf" for portability,
-so hopefully we work on more platforms than that. However, it is likely that we
-missed something and that minor porting is required to get LLVM to work on new
-platforms. We welcome portability patches and error messages.</p>
+<p>LLVM is known to work on the following platforms:</p>
-</div>
+<ul>
+ <li>Intel and AMD machines running Red Hat Linux, Fedora Core and FreeBSD
+ (and probably other unix-like systems).</li>
+<li>Sun UltraSPARC workstations running Solaris 8.</li>
+<li>Intel and AMD machines running on Win32 with the Cygwin libraries (limited
+ support is available for native builds with Visual C++).</li>
+<li>PowerPC and X86-based Mac OS X systems, running 10.2 and above.</li>
+<li>Alpha-based machines running Debian GNU/Linux.</li>
+<li>Itanium-based machines running Linux and HP-UX.</li>
+</ul>
-<!--=========================================================================-->
-<div class="doc_subsection">
-In this release, the following portability problems were fixed:
-</div>
+<p>The core LLVM infrastructure uses
+<a href="http://www.gnu.org/software/autoconf/">GNU autoconf</a> to adapt itself
+to the machine and operating system on which it is built. However, minor
+porting may be required to get LLVM to work on new platforms. We welcome your
+portability patches and reports of successful builds or error messages.</p>
-<ol>
-<li><a href="http://llvm.cs.uiuc.edu/PR304">warnings compiling Stacker compiler on Mac OS X</a></li>
-<li><a href="http://llvm.cs.uiuc.edu/PR308">Archive file reader doesn't understand abbreviated names in headers</a></li>
-</ol>
+</div>
<!-- *********************************************************************** -->
<div class="doc_section">
<p>This section contains all known problems with the LLVM system, listed by
component. As new problems are discovered, they will be added to these
sections. If you run into a problem, please check the <a
-href="http://llvm.cs.uiuc.edu/bugs/">LLVM bug database</a> and submit a bug if
+href="http://llvm.org/bugs/">LLVM bug database</a> and submit a bug if
there isn't already one.</p>
</div>
<div class="doc_text">
-<p>
-The following components of this LLVM release are either untested, known to be
-broken or unreliable, or are in early development. These components should not
-be relied on, and bugs should not be filed against them, but they may be useful
-to some people. In particular, if you would like to work on one of these
-components, please contact us on the llvmdev list.
-</p>
+<p>The following components of this LLVM release are either untested, known to
+be broken or unreliable, or are in early development. These components should
+not be relied on, and bugs should not be filed against them, but they may be
+useful to some people. In particular, if you would like to work on one of these
+components, please contact us on the llvmdev list.</p>
<ul>
-<li>The following passes are incomplete or buggy: <tt>-pgmdep, -memdep,
- -ipmodref, -sortstructs, -swapstructs, -cee</tt></li>
-
-<li>The <tt>-pre</tt> pass is incomplete (there are cases it doesn't handle that
- it should) and not thoroughly tested.</li>
-<li>The <tt>llvm-ar</tt> tool is incomplete and probably buggy.</li>
-<li>The <tt>llvm-db</tt> tool is in a very early stage of development.</li>
+<li>The following passes are incomplete or buggy, and may be removed in future
+ releases: <tt>-cee, -pre</tt></li>
+<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
+ be used to step through programs and inspect the stack.</li>
+<li>The SparcV8 and IA64 code generators are experimental.</li>
+<li>The Alpha JIT is experimental.</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="core">Known problems with the LLVM Core</a>
+ <a name="build">Known problems with the Build System</a>
</div>
<div class="doc_text">
<ul>
+ <li>The <a href="http://llvm.org/PR656">configure script sometimes fails on Solaris/Sparc</a>. A work around is documented in <a href="http://llvm.org/PR656">PR656.</a></li>
+</ul>
+</div>
-<li>In the JIT, <tt>dlsym</tt> on a symbol compiled by the JIT will not
-work.</li>
-
-<li>The JIT does not use mutexes to protect its internal data structures. As
-such, execution of a threaded program could cause these data structures to be
-corrupted.</li>
-
-<li>It is not possible to <tt>dlopen</tt> an LLVM bytecode file in the JIT.</li>
-<li>Linking in static archive files (.a files) is very slow (there is no symbol
-table in the archive).</li>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="core">Known problems with the LLVM Core</a>
+</div>
-<li>The gccld program <a href="http://llvm.cs.uiuc.edu/PR139">does not link
-objects/archives in the order specified on the command line.</a></li>
+<div class="doc_text">
-<li><a href="http://llvm.cs.uiuc.edu/PR240">The lower-invoke pass does not mark
-values live across a setjmp as volatile</a>. This missing feature only affects
-targets whose setjmp/longjmp libraries do not save and restore the entire
-register file.</li>
+<ul>
+ <li>In the JIT, <tt>dlsym()</tt> on a symbol compiled by the JIT will not
+ work.</li>
</ul>
</div>
}
</pre></li>
-<li>
-Initialization of global union variables can only be done
-<a href="http://llvm.cs.uiuc.edu/bugs/show_bug.cgi?id=162">with the largest
-union member</a>.
-</li>
-
-<li><a href="http://llvm.cs.uiuc.edu/PR244">[llvm-gcc] Error when an implicitly
-external function is re-declared as static</a></li>
+<li>Initialization of global union variables can only be done <a
+href="http://llvm.org/PR162">with the largest union member</a>.</li>
</ul>
</div>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>: Defining variables residing in specified registers.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Vector-Extensions.html#Vector%20Extensions">Vector Extensions</a>: Using vector instructions through built-in functions.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Target-Builtins.html#Target%20Builtins">Target Builtins</a>: Built-in functions specific to particular targets.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread-Local.html#Thread-Local">Thread-Local</a>: Per-thread variables.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Thread_002dLocal.html">Thread-Local</a>: Per-thread variables.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Pragmas.html#Pragmas">Pragmas</a>: Pragmas accepted by GCC.</li>
</ol>
return.<br>
<b>Supported:</b> <tt>format</tt>, <tt>format_arg</tt>, <tt>non_null</tt>,
- <tt>constructor</tt>, <tt>destructor</tt>, <tt>unused</tt>,
+ <tt>noreturn</tt>, <tt>constructor</tt>, <tt>destructor</tt>,
+ <tt>unused</tt>,
<tt>deprecated</tt>, <tt>warn_unused_result</tt>, <tt>weak</tt><br>
- <b>Ignored:</b> <tt>noreturn</tt>, <tt>noinline</tt>,
+ <b>Ignored:</b> <tt>noinline</tt>,
<tt>always_inline</tt>, <tt>pure</tt>, <tt>const</tt>, <tt>nothrow</tt>,
<tt>malloc</tt>, <tt>no_instrument_function</tt>, <tt>cdecl</tt><br>
We support all builtins which have a C language equivalent (e.g.,
<tt>__builtin_cos</tt>), <tt>__builtin_alloca</tt>,
<tt>__builtin_types_compatible_p</tt>, <tt>__builtin_choose_expr</tt>,
- <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt> (ignored).</li>
-
+ <tt>__builtin_constant_p</tt>, and <tt>__builtin_expect</tt>
+ (currently ignored). We also support builtins for ISO C99 floating
+ point comparison macros (e.g., <tt>__builtin_islessequal</tt>),
+ <tt>__builtin_prefetch</tt>, <tt>__builtin_popcount[ll]</tt>,
+ <tt>__builtin_clz[ll]</tt>, and <tt>__builtin_ctz[ll]</tt>.</li>
</ol>
<p>The following extensions <b>are</b> known to be supported:</p>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html#Labels%20as%20Values">Labels as Values</a>: Getting pointers to labels and computed gotos.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement%20Exprs">Statement Exprs</a>: Putting statements and declarations inside expressions.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Typeof.html#Typeof">Typeof</a>: <code>typeof</code>: referring to the type of an expression.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc-3.4.0/gcc/Lvalues.html#Lvalues">Lvalues</a>: Using <code>?:</code>, "<code>,</code>" and casts in lvalues.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Conditionals.html#Conditionals">Conditionals</a>: Omitting the middle operand of a <code>?:</code> expression.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html#Long%20Long">Long Long</a>: Double-word integers.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Complex.html#Complex">Complex</a>: Data types for complex numbers.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Case-Ranges.html#Case%20Ranges">Case Ranges</a>: `case 1 ... 9' and such.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Mixed-Declarations.html#Mixed%20Declarations">Mixed Declarations</a>: Mixing declarations and code.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Function-Prototypes.html#Function%20Prototypes">Function Prototypes</a>: Prototype declarations and old-style definitions.</li>
- <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C---Comments.html#C++%20Comments">C++ Comments</a>: C++ comments are recognized.</li>
+ <li><a href="http://gcc.gnu.org/onlinedocs/gcc/C_002b_002b-Comments.html#C_002b_002b-Comments">C++ Comments</a>: C++ comments are recognized.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Dollar-Signs.html#Dollar%20Signs">Dollar Signs</a>: Dollar sign is allowed in identifiers.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Character-Escapes.html#Character%20Escapes">Character Escapes</a>: <code>\e</code> stands for the character <ESC>.</li>
<li><a href="http://gcc.gnu.org/onlinedocs/gcc/Alignment.html#Alignment">Alignment</a>: Inquiring about the alignment of a type or variable.</li>
<div class="doc_text">
-<p>For this release, the C++ front-end is considered to be fully functional but
-has not been tested as thoroughly as the C front-end. It has been tested and
-works for a number of non-trivial programs, but there may be lurking bugs.
-Please report any bugs or problems.</p>
+<p>For this release, the C++ front-end is considered to be fully
+tested and works for a number of non-trivial programs, including LLVM
+itself.</p>
</div>
<ul>
<li>The C++ front-end inherits all problems afflicting the <a href="#c-fe">C
front-end</a>.</li>
+
</ul>
+
</div>
<!-- _______________________________________________________________________ -->
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="c-be">Known problems with the C back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+
+<li>The C back-end produces code that violates the ANSI C Type-Based Alias
+Analysis rules. As such, special options may be necessary to compile the code
+(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
+problem probably cannot be fixed.</li>
+
+<li><a href="http://llvm.org/PR56">Zero arg vararg functions are not
+supported</a>. This should not affect LLVM produced by the C or C++
+frontends.</li>
+
+</ul>
+
+</div>
+
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="x86-be">Known problems with the X86 back-end</a>
<div class="doc_text">
<ul>
-<li>None so far.
+<li><a href="http://llvm.org/PR566">Memory Mapped I/O Intrinsics do not fence
+memory</a></li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="sparc-be">Known problems with the Sparc back-end</a>
+ <a name="ppc-be">Known problems with the PowerPC back-end</a>
</div>
<div class="doc_text">
<ul>
-<li>There are several programs in the LLVM testsuite that the Sparc code generator is known to miscompile.</li>
+<li>None yet</li>
</ul>
</div>
<!-- ======================================================================= -->
<div class="doc_subsection">
- <a name="c-be">Known problems with the C back-end</a>
+ <a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
</div>
<div class="doc_text">
<ul>
+<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
+several programs in the LLVM test suite</a></li>
+</ul>
-<li>The C back-end produces code that violates the ANSI C Type-Based Alias
-Analysis rules. As such, special options may be necessary to compile the code
-(for example, GCC requires the <tt>-fno-strict-aliasing</tt> option). This
-problem probably cannot be fixed.</li>
+</div>
-<li><a href="http://llvm.cs.uiuc.edu/PR33">Initializers for global variables</a>
-cannot include special floating point numbers like Not-A-Number or
-Infinity.</li>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="alpha-be">Known problems with the Alpha back-end</a>
+</div>
-<li><a href="http://llvm.cs.uiuc.edu/PR56">Zero arg vararg functions are not
-supported</a>. This should not affect LLVM produced by the C or C++
-frontends.</li>
+<div class="doc_text">
+
+<ul>
+
+<li>On 21164s, some rare FP arithmetic sequences which may trap do not have the
+appropriate nops inserted to ensure restartability.</li>
</ul>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="ia64-be">Known problems with the IA64 back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+
+<li>C++ programs are likely to fail on IA64, as calls to <tt>setjmp</tt> are
+made where the argument is not 16-byte aligned, as required on IA64. (Strictly
+speaking this is not a bug in the IA64 back-end; it will also be encountered
+when building C++ programs using the C back-end.)</li>
+
+<li>The C++ front-end does not use <a href="http://llvm.org/PR406">IA64
+ABI compliant layout of v-tables</a>. In particular, it just stores function
+pointers instead of function descriptors in the vtable. This bug prevents
+mixing C++ code compiled with LLVM with C++ objects compiled by other C++
+compilers.</li>
+
+<li>There are a few ABI violations which will lead to problems when mixing LLVM
+output with code built with other compilers, particularly for floating-point
+programs.</li>
+
+<li>Defining vararg functions is not supported (but calling them is ok).</li>
+
+</ul>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="sparcv8">Known problems with the SPARC-V8 back-end</a>
+</div>
+
+<div class="doc_text">
+
+<ul>
+<li>Many features are still missing (e.g. support for 64-bit integer
+arithmetic). This back-end is in pre-beta state.</li>
+</ul>
+</div>
+
<!-- *********************************************************************** -->
<div class="doc_section">
<a name="additionalinfo">Additional Information</a>
<div class="doc_text">
-<p>A wide variety of additional information is available on the LLVM web page,
-including mailing lists and publications describing algorithms and components
-implemented in LLVM. The web page also contains versions of the API
-documentation which is up-to-date with the CVS version of the source code. You
-can access versions of these documents specific to this release by going into
-the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
+<p>A wide variety of additional information is available on the <a
+href="http://llvm.org">LLVM web page</a>, including <a
+href="http://llvm.org/docs/">documentation</a> and <a
+href="http://llvm.org/pubs/">publications describing algorithms and
+components implemented in LLVM</a>. The web page also contains versions of the
+API documentation which is up-to-date with the CVS version of the source code.
+You can access versions of these documents specific to this release by going
+into the "<tt>llvm/doc/</tt>" directory in the LLVM tree.</p>
<p>If you have any questions or comments about LLVM, please feel free to contact
-us via the <a href="http://mail.cs.uiuc.edu/mailman/listinfo/llvmdev">mailing
+us via the <a href="http://llvm.org/docs/#maillist"> mailing
lists</a>.</p>
</div>
<a href="http://validator.w3.org/check/referer"><img
src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
- <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
+ <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Last modified: $Date$
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