add a bunch of stuff, pieces still missing
llvm-svn: 27796
This commit is contained in:
Chris Lattner
parent
9232c8c1c5
commit
9f87173df3
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@ -4,7 +4,7 @@
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<link rel="stylesheet" href="llvm.css" type="text/css">
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<title>LLVM 1.7cvs Release Notes</title>
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<title>LLVM 1.7 Release Notes</title>
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</head>
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<body>
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@ -60,38 +60,152 @@ href="http://llvm.org/releases/">releases page</a>.</p>
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<div class="doc_text">
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<p>This is the seventh public release of the LLVM Compiler Infrastructure. This
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release incorporates a large number of enhancements and additions (primarily in
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the code generator), which combine to improve the quality of the code generated
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by LLVM by up to 30% in some cases. This release is also the first release to
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have first-class support for Mac OS X: all of the major bugs have been shaken
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out and it is now as well supported as Linux on X86.</p>
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<p>This is the eighth public release of the LLVM Compiler Infrastructure. This
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release incorporates a large number of enhancements and new features,
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including vector support (Intel SSE and Altivec), a new GCC4.0-based
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C/C++ front-end, Objective C/C++ support, inline assembly support, and many
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other big features.
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</p>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="newfeatures">New Features in LLVM 1.7cvs</a>
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<a name="newfeatures">New Features in LLVM 1.7</a>
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</div>
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<!--_________________________________________________________________________-->
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<div class="doc_subsubsection"><a name="llvmgcc4">GCC4.0-based llvm-gcc
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front-end</a></div>
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<div class="doc_text">
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<p>LLVM 1.8 includes a brand new llvm-gcc, based on GCC 4.0.1. This version
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of llvm-gcc solves many serious long-standing problems with llvm-gcc, including
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all of those blocked by the <a href="http://llvm.org/PR498">llvm-gcc 4 meta
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bug</a>. In addition, llvm-gcc4 implements support for many new features,
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including GCC inline assembly, generic vector support, SSE and Altivec
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intrinsics, and several new GCC attributes. In addition, llvm-gcc4 is
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significantly faster than llvm-gcc3, respects -O options, its -c/-S options
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correspond to GCC's (they emit native code).</p>
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<p>If you can use it, llvm-gcc4 is offers significant new functionality, and we
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hope that it will replace llvm-gcc3 completely in a future release.
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Unfortunately, it does not currently support C++ exception handling at all, and
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it only works on Apple Mac OS/X machines with X86 or PowerPC processors.
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</p>
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</div>
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<!--_________________________________________________________________________-->
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<div class="doc_subsubsection"><a name="inlineasm">Inline Assembly
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Support</a></div>
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<div class="doc_text">
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<p>The LLVM IR and llvm-gcc4 front-end now fully support arbitrary GCC <a
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href="LangRef.html#inlineasm">inline assembly</a>. The LLVM X86 and PowerPC
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code generators have initial support for it,
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being able to compile basic statements, but are missing some features. Please
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report any inline asm statements that crash the compiler or that are miscompiled
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as bugs.</p>
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</div>
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<!--_________________________________________________________________________-->
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<div class="doc_subsubsection"><a name="newsparc">New SPARC backend</a></div>
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<div class="doc_text">
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<p>LLVM 1.7 includes a new, fully functional, SPARC backend built in the
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target-independent code generator. This SPARC backend includes support for
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SPARC V8 and SPARC V9 subtargets (controlling whether V9 features can be used),
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and targets the 32-bit SPARC ABI.</p>
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<p>The LLVM 1.7 release is the last release that will include the LLVM "SparcV9"
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backend, which was the very first LLVM native code generator. In 1.8, it will
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be removed, replaced with the new SPARC backend.</p>
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</div>
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<!--_________________________________________________________________________-->
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<div class="doc_subsubsection"><a name="genvector">Generic Vector Support
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</a></div>
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<div class="doc_text">
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<p>LLVM now includes significantly extended support for SIMD vectors in its
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core instruction set. It now includes three new instructions for manipulating
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vectors: <a href="LangRef.html#i_extractelement"><tt>extractelement</tt></a>,
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<a href="LangRef.html#i_insertelement"><tt>insertelement</tt></a>, and
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<a href="LangRef.html#i_shufflevector"><tt>shufflevector</tt></a>. Further,
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many bugs in vector handling have been fixed, and vectors are now supported by
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the target-independent code generator. For example, if a vector operation is
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not supported by a particular target, it will be correctly broken down and
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executed as scalar operations.</p>
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<p>Because llvm-gcc3 does not support GCC generic vectors or vector intrinsics,
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so llvm-gcc4 must be used.</p>
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</div>
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<!--_________________________________________________________________________-->
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<div class="doc_subsubsection"><a name="ssealtivec">Intel SSE and PowerPC
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Altivec support
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</a></div>
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<div class="doc_text">
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<p>The LLVM X86 backend now supports Intel SSE 1, 2, and 3, and now uses scalar
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SSE operations to implement scalar floating point math when the target supports
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SSE1 (for floats) or SSE2 (for doubles). Vector SSE instructions are generated
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by llvm-gcc4 when the generic vector mechanism or specific SSE intrinsics are
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used.
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</p>
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<p>The LLVM PowerPC backend now supports the Altivec instruction set, including
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both GCC -maltivec and -faltivec modes. Altivec instructions are generated
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by llvm-gcc4 when the generic vector mechanism or specific Altivec intrinsics
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are used.
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</p>
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</div>
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<!--_________________________________________________________________________-->
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<div class="doc_subsubsection"><a name="othernew">Other New Features</a></div>
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<div class="doc_text">
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<ul>
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<li>New C front-end.</li>
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<li>New SPARC backend.</li>
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<li>Inline assembly support.</li>
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<li>foo</li>
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</ul>
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</div>
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<!--=========================================================================-->
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<div class="doc_subsection">
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<a name="changes">Significant changes in LLVM 1.7cvs</a>
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<a name="changes">Significant Changes in LLVM 1.7</a>
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</div>
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<div class="doc_text">
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<ul>
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<li>Removed the llvm.readport/llvm.writeport/llvm.readio/llvm.writeio
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intrinsics.</li>
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<li>Separated the other intrinsics based on type.</li>
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<li>The LLVM intrinsics used to be overloaded based on type: for example,
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<a href="LangRef.html#int_ctpop"><tt>llvm.ctpop</tt></a> could work with any
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integer datatype. They are now separated into different intrinsics with
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suffixes to denote their argument type (e.g. <tt>llvm.ctpop.i32</tt>)). Old
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LLVM .ll and .bc files that use these intrinsics will continue to work with
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new LLVM versions (they are transparently upgraded by the parsers), but will
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cause a warning to be emitted.</li>
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<li>The <tt>llvm.readport</tt>, <tt>llvm.writeport</tt>, <tt>llvm.readio</tt>,
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and <tt>llvm.writeio</tt> intrinsics have been removed. The first two
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were ever only supported by the X86 backend, the last two were never
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correctly supported by any target, and none were accessible through the
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C front-end. Inline assembly support can now be used to
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implement these operations.</li>
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<li>The <tt>llvm-db</tt> tool had basic support for stepping through code, which
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used the JIT. This code has been removed, and DWARF emission support added
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instead. <tt>llvm-db</tt> still exists in CVS if someone wanted to write a
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<tt>ptrace</tt> backend for it.</li>
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</ul>
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</div>
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@ -155,12 +269,12 @@ useful to some people. In particular, if you would like to work on one of these
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components, please contact us on the llvmdev list.</p>
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<ul>
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<li>The following passes are incomplete or buggy, and may be removed in future
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releases: <tt>-cee</tt></li>
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<li>The <tt>llvm-db</tt> tool is in a very early stage of development, but can
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be used to step through programs and inspect the stack.</li>
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<li>The <tt>-cee</tt> pass is known to be buggy, and may be removed in in a
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future release.</li>
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<li>The IA64 code generator is experimental.</li>
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<li>The Alpha JIT is experimental.</li>
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<li>"<tt>-filetype=asm</tt>" (the default) is the only supported value for the
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<tt>-filetype</tt> llc option.</li>
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</ul>
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</div>
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@ -201,11 +315,14 @@ components, please contact us on the llvmdev list.</p>
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<div class="doc_text">
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These bugs are known for the old front-end. The new GCC-4-based C front-end
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suffers from none of these.
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<p>
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llvm-gcc3 has many significant problems that are fixed by llvm-gcc4. See
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those blocked on the <a href="http://llvm.org/PR498">llvm-gcc4 meta bug</a>.
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Two signicant ones include:</p>
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<ul>
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<li>C99 Variable sized arrays do not release stack memory when they go out of
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<li>With llvm-gcc3,
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C99 variable sized arrays do not release stack memory when they go out of
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scope. Thus, the following program may run out of stack space:
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<pre>
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for (i = 0; i != 1000000; ++i) {
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@ -214,7 +331,7 @@ suffers from none of these.
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}
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</pre></li>
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<li>Initialization of global union variables can only be done <a
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<li>With llvm-gcc3, Initialization of global union variables can only be done <a
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href="http://llvm.org/PR162">with the largest union member</a>.</li>
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</ul>
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@ -398,11 +515,6 @@ itself.</p>
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<ul>
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<li>The C++ front-end is based on a pre-release of the GCC 3.4 C++ parser. This
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parser is significantly more standards compliant (and picky) than prior GCC
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versions. For more information, see the C++ section of the <a
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href="http://gcc.gnu.org/gcc-3.4/changes.html">GCC 3.4 release notes</a>.</li>
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<li>Destructors for local objects are not always run when a <tt>longjmp</tt> is
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performed. In particular, destructors for objects in the <tt>longjmp</tt>ing
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function and in the <tt>setjmp</tt> receiver function may not be run.
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@ -442,6 +554,12 @@ problem probably cannot be fixed.</li>
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supported</a>. This should not affect LLVM produced by the C or C++
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frontends.</li>
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<li>The C backend does not correctly implement the <a
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href="LangRef.html#i_stacksave"><tt>llvm.stacksave</tt></a> or
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<a href="LangRef.html#i_stackrestore"><tt>llvm.stackrestore</tt></a>
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intrinsics. This means that some code compiled by it can run out of stack
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space if they depend on these (e.g. C99 varargs).</li>
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</ul>
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</div>
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@ -454,7 +572,8 @@ frontends.</li>
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<div class="doc_text">
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<ul>
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<li>None yet</li>
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<li><a href="http://llvm.org/PR736">Indirect calls crash JIT on
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Darwin/x86</a>.</li>
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</ul>
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</div>
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@ -467,21 +586,8 @@ frontends.</li>
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<div class="doc_text">
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<ul>
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<li>None yet</li>
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</ul>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
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</div>
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<div class="doc_text">
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<ul>
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<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
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several programs in the LLVM test suite</a></li>
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<li><a href="http://llvm.org/PR642">PowerPC backend does not correctly
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implement ordered FP comparisons</a>.</li>
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</ul>
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</div>
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@ -534,14 +640,32 @@ programs.</li>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="sparc">Known problems with the SPARC back-end</a>
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<a name="sparc-be">Known problems with the SPARC back-end</a>
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</div>
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<div class="doc_text">
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<ul>
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<li>None yet.</li>
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<li>None yet</li>
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</ul>
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</div>
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<!-- ======================================================================= -->
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<div class="doc_subsection">
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<a name="sparcv9-be">Known problems with the SparcV9 back-end</a>
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</div>
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<div class="doc_text">
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<ul>
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<li><a href="http://llvm.org/PR60">[sparcv9] SparcV9 backend miscompiles
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several programs in the LLVM test suite</a></li>
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<li>The SparcV9 backend is slated to be removed before the LLVM 1.8
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release.</li>
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</ul>
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</div>
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<!-- *********************************************************************** -->
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