Changes in directory llvm/docs:
ReleaseNotes.html updated: 1.358 -> 1.359 --- Log message: First draft of the llvm 1.8 release notes. --- Diffs of the changes: (+77 -162) ReleaseNotes.html | 239 +++++++++++++++++------------------------------------- 1 files changed, 77 insertions(+), 162 deletions(-) Index: llvm/docs/ReleaseNotes.html diff -u llvm/docs/ReleaseNotes.html:1.358 llvm/docs/ReleaseNotes.html:1.359 --- llvm/docs/ReleaseNotes.html:1.358 Wed Apr 19 23:24:28 2006 +++ llvm/docs/ReleaseNotes.html Tue Aug 8 12:27:28 2006 @@ -4,11 +4,11 @@ <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <link rel="stylesheet" href="llvm.css" type="text/css"> - <title>LLVM 1.7 Release Notes</title> + <title>LLVM 1.8 Release Notes</title> </head> <body> -<div class="doc_title">LLVM 1.7 Release Notes</div> +<div class="doc_title">LLVM 1.8 Release Notes</div> <ol> <li><a href="#intro">Introduction</a></li> @@ -32,9 +32,10 @@ <div class="doc_text"> <p>This document contains the release notes for the LLVM compiler -infrastructure, release 1.7. Here we describe the status of LLVM, including any +infrastructure, release 1.8. 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 +up-to-date version of this document (corresponding to LLVM CVS) can be found +on the <a href="http://llvm.org/releases/";>LLVM releases 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> @@ -62,38 +63,30 @@ <p>This is the eighth public release of the LLVM Compiler Infrastructure. This release incorporates a large number of enhancements and new features, -including vector support (Intel SSE and Altivec), a new GCC4.0-based -C/C++ front-end, Objective C/C++ support, inline assembly support, and many -other big features. +including DWARF debugging support (C and C++ on Darwin/PPC), improved inline +assembly support, a new <a href="http://llvm.org/nightlytest/";>nightly +tester</a>, llvm-config enhancments, many bugs +fixed, and performance and compile time improvements. </p> </div> <!--=========================================================================--> <div class="doc_subsection"> -<a name="newfeatures">New Features in LLVM 1.7</a> +<a name="newfeatures">New Features in LLVM 1.8</a> </div> <!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="llvmgcc4">GCC4.0-based llvm-gcc -front-end</a></div> +<div class="doc_subsubsection"><a name="dwarf">DWARF debugging +support </a></div> <div class="doc_text"> -<p>LLVM 1.7 includes a brand new llvm-gcc, based on GCC 4.0.1. This version -of llvm-gcc solves many serious long-standing problems with llvm-gcc, including -all of those blocked by the <a href="http://llvm.org/PR498";>llvm-gcc 4 meta -bug</a>. In addition, llvm-gcc4 implements support for many new features, -including GCC inline assembly, generic vector support, SSE and Altivec -intrinsics, and several new GCC attributes. Finally, llvm-gcc4 is -significantly faster than llvm-gcc3, respects -O options, its -c/-S options -correspond to GCC's (they emit native code), supports Objective C/C++, and -it has debugging support well underway.</p> - -<p>If you can use it, llvm-gcc4 offers significant new functionality, and we -hope that it will replace llvm-gcc3 completely in a future release. -Unfortunately, it does not currently support C++ exception handling at all, and -it only works on Apple Mac OS/X machines with X86 or PowerPC processors. +<p>The llvm-gcc4 C front-end now generates debugging info for C and C++. This +information is propagated through the compiler and the code generator can +currently produce DWARF debugging information from it. DWARF is a standard +debugging format used on many platforms, but currently LLVM only includes +target support for Mac OS X targets for the 1.8 release. </p> </div> @@ -104,174 +97,96 @@ <div class="doc_text"> -<p>The LLVM IR and llvm-gcc4 front-end now fully support arbitrary GCC <a -href="LangRef.html#inlineasm">inline assembly</a>. The LLVM X86 and PowerPC -code generators have initial support for it, -being able to compile basic statements, but are missing some features. Please -report any inline asm statements that crash the compiler or that are miscompiled -as bugs.</p> +<p>Inline assembly support is substantially improved in LLVM 1.8 over LLVM 1.7. +Many unsupported features are now supported, and inline asm support in the X86 +backend is far better. llvm-gcc4 now supports global register variables as +well.</p> </div> <!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="newsparc">New SPARC backend</a></div> +<div class="doc_subsubsection"><a name="loopopt">Loop Optimizer Improvements</a></div> <div class="doc_text"> -<p>LLVM 1.7 includes a new, fully functional, SPARC backend built in the -target-independent code generator. This SPARC backend includes support for -SPARC V8 and SPARC V9 subtargets (controlling whether V9 features can be used), -and targets the 32-bit SPARC ABI.</p> - -<p>The LLVM 1.7 release is the last release that will include the LLVM "SparcV9" -backend, which was the very first LLVM native code generator. It will -be removed in LLVM 1.8, being replaced with the new SPARC backend.</p> +<p>The Loop Optimizer pass now used "Loop-Closed SSA Form", which makes it +easier to update SSA form as loop transformations change the code. An +immediate benefit of this is that the loop unswitching pass can now unswitch +loops in more cases. +</p> </div> <!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="genvector">Generic Vector Support +<div class="doc_subsubsection"><a name="jumptab">Jump Table Support for Switches </a></div> <div class="doc_text"> -<p>LLVM now includes significantly extended support for SIMD vectors in its -core instruction set. It now includes three new instructions for manipulating -vectors: <a href="LangRef.html#i_extractelement"><tt>extractelement</tt></a>, -<a href="LangRef.html#i_insertelement"><tt>insertelement</tt></a>, and -<a href="LangRef.html#i_shufflevector"><tt>shufflevector</tt></a>. Further, -many bugs in vector handling have been fixed, and vectors are now supported by -the target-independent code generator. For example, if a vector operation is -not supported by a particular target, it will be correctly broken down and -executed as scalar operations.</p> +<p>The code generator now lowers switch statements to jump tables, providing +significant performance boosts for applications (e.g. interpreters) whose +performance is highly correlated to switch statement performance.</p> -<p>Because llvm-gcc3 does not support GCC generic vectors or vector intrinsics, -llvm-gcc4 must be used.</p> </div> - <!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="ssealtivec">Intel SSE and PowerPC -Altivec support +<div class="doc_subsubsection"><a name="jitrelease">Deallocation of JIT'd +Machine Code </a></div> <div class="doc_text"> -<p>The LLVM X86 backend now supports Intel SSE 1, 2, and 3, and now uses scalar -SSE operations to implement scalar floating point math when the target supports -SSE1 (for floats) or SSE2 (for doubles). Vector SSE instructions are generated -by llvm-gcc4 when the generic vector mechanism or specific SSE intrinsics are -used. -</p> - -<p>The LLVM PowerPC backend now supports the Altivec instruction set, including -both GCC -maltivec and -faltivec modes. Altivec instructions are generated -by llvm-gcc4 when the generic vector mechanism or specific Altivec intrinsics -are used. +<p>The LLVM JIT now allows clients to deallocate machine code JIT'd to its code +buffer. This is important for long living applications that depend on the JIT. </p> </div> <!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="optimizernew">Optimizer -Improvements</a></div> +<div class="doc_subsubsection"><a name="other">Other Improvements</a></div> <div class="doc_text"> -<ul> -<li>The Loop Unswitching pass (<tt>-loop-unswitch</tt>) has had several bugs - fixed, has several new features, and is enabled by default in llvmgcc3 - now.</li> -<li>The Loop Strength Reduction pass (<tt>-loop-reduce</tt>) is now enabled for - the X86 and Alpha backends.</li> -<li>The Instruction Combining pass (<tt>-instcombine</tt>) now includes a - framework and implementation for simplifying code based on whether computed - bits are demanded or not.</li> -<li>The Scalar Replacement of Aggregates pass (<tt>-scalarrepl</tt>) can now - promote simple unions to registers.</li> -<li>The Reassociation pass (<tt>-reassociate</tt>) can now - factor expressions, e.g. turning "A*A+A*B" into "A*(A+B)".</li> -<li>Several LLVM passes are <a href="http://llvm.org/PR681";>significantly -faster</a>.</li> -</ul> -</div> -<!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="codgennew">Code Generator -Improvements</a></div> +<p>This release includes many other improvements, including improvements to + the optimizers and code generators (improving the generated code) changes to + speed up the compiler in many ways (improving algorithms and fine tuning + code), and changes to reduce the code size of the compiler itself.</p> + +<p>More specific changes include:</p> + +<ul> +<li>LLVM 1.8 includes an initial ARM backend. This backend is in early + development stages.</li> +<li>LLVM 1.8 now includes significantly better support for mingw and + cygwin.</li> +<li>The <a href="CommandGuide/html/llvm-config.html">llvm-config</a> tool is + now built by default and has several new features.</li> +<li>The X86 and PPC backends now use the correct platform ABI for passing + vectors as arguments to functions.</li> +<li>The X86 backend now includes support for the Microsoft ML assembler + ("MASM").</li> +<li>The PowerPC backend now pattern matches the 'rlwimi' instruction more + aggressively.</li> +<li>Most of LLVM is now built with "-pedantic", ensuring better portability + to more C++ Compilers.</li> +<li>The PowerPC backend now includes initial 64-bit support. The JIT is not + complete, and the static compiler has a couple of known bugs, but support + is mostly in place. LLVM 1.9 will include completed PPC-64 support. </li> -<div class="doc_text"> -<ul> -<li>LLVM has a new prepass (before register allocation) list scheduler, which - supports bottom-up and top-down scheduling, pluggable priority functions and - pluggable hazard recognizers. The X86 backend uses this to reduce register - pressure and RISC targets schedule based on operation latency.</li> -<li>The tblgen-based target description framework introduced in LLVM 1.6 has - several new features, useful for targets that can fold loads and stores into - operations, and features that make the .td files more expressive.</li> -<li>The instruction selector is significantly faster in 1.7 than in 1.6.</li> -<li>The X86, Alpha and Itanium backends use new DAG-DAG instruction selectors, - making them easier to maintain and generate slightly better code.</li> -<li>The X86 backend now supports generation of Scalar SSE code for scalar FP - expressions. LLVM provides significantly better performance with Scalar SSE - instructions than it does with the Intel floating point stack - instructions.</li> -<li>The Itanium backend now has a bundling pass, which improves performance - by ~10% and reduces code size (previously it unconditionally inserted a stop - bit after every instruction).</li> </ul> </div> -<!--_________________________________________________________________________--> -<div class="doc_subsubsection"><a name="othernew">Other New Features</a></div> - -<div class="doc_text"> -<ul> -<li>The Mac OS/X PowerPC and X86 backends now have initial support for - Darwin DWARF - debugging information, however, debug info generation has been disabled for - the 1.7 release in llvmgcc4.</li> -<li>LLVM includes the new <a href="docs/CommandGuide/html/llvm-config.html"> - llvm-config</a> utility, which makes it easier to build and link programs - against the LLVM libraries when not using the LLVM makefiles.</li> -<li>LLVM now supports first class global ctor/dtor initialization lists, no - longer forcing targets to use "__main".</li> -<li>LLVM supports assigning globals and functions to a particular section - in the result executable using the GCC section attribute.</li> -<li><a href="ExtendingLLVM.html">Adding intrinsics to LLVM</a> is now - significantly easier.</li> -<li>llvmgcc4 now fully supports C99 Variable Length Arrays, including dynamic - stack deallocation.</li> - -</ul> -</div> - - <!--=========================================================================--> <div class="doc_subsection"> -<a name="changes">Significant Changes in LLVM 1.7</a> +<a name="changes">Significant Changes in LLVM 1.8</a> </div> <div class="doc_text"> <ul> -<li>The official LLVM URL is now <a href="http://llvm.org/";> - http://llvm.org/</a>.</li> -<li>The LLVM intrinsics used to be overloaded based on type: for example, - <a href="LangRef.html#int_ctpop"><tt>llvm.ctpop</tt></a> could work with any - integer datatype. They are now separated into different intrinsics with - suffixes to denote their argument type (e.g. <tt>llvm.ctpop.i32</tt>)). Old - LLVM .ll and .bc files that use these intrinsics will continue to work with - new LLVM versions (they are transparently upgraded by the parsers), but will - cause a warning to be emitted.</li> -<li>The <tt>llvm.readport</tt>, <tt>llvm.writeport</tt>, <tt>llvm.readio</tt>, - and <tt>llvm.writeio</tt> intrinsics have been removed. The first two - were ever only supported by the X86 backend, the last two were never - correctly supported by any target, and none were accessible through the - C front-end. Inline assembly support can now be used to - implement these operations.</li> -<li>The <tt>llvm-db</tt> tool had basic support for stepping through code, which - used the JIT. This code has been removed, and DWARF emission support added - instead. <tt>llvm-db</tt> still exists in CVS if someone wanted to write a - <tt>ptrace</tt> backend for it.</li> +<li>The LLVM "SparcV9" backend (deprecated in LLVM 1.7) has been removed in +LLVM 1.8. The LLVM "Sparc" backend replaces it.</li> +<li>The --version option now prints more useful information, including the + build configuration for the tool.</li> </ul> </div> @@ -382,8 +297,7 @@ <div class="doc_text"> <p> -llvm-gcc3 has many significant problems that are fixed by llvm-gcc4. See - those blocked on the <a href="http://llvm.org/PR498";>llvm-gcc4 meta bug</a>. +llvm-gcc3 has many significant problems that are fixed by llvm-gcc4. Two major ones include:</p> <ul> @@ -401,6 +315,11 @@ href="http://llvm.org/PR162";>with the largest union member</a>.</li> </ul> + +<p>llvm-gcc4 is far more stable and produces better code than llvm-gcc3, but +does not currently support Link-Time-Optimization or C++ Exception Handling, +which llvm-gcc3 does.</p> + </div> <!-- _______________________________________________________________________ --> @@ -638,8 +557,7 @@ <div class="doc_text"> <ul> -<li><a href="http://llvm.org/PR736";>Indirect calls crash JIT on -Darwin/x86</a>.</li> +<li>none yet.</li> </ul> </div> @@ -718,19 +636,16 @@ </div> - <!-- ======================================================================= --> <div class="doc_subsection"> - <a name="sparcv9-be">Known problems with the SparcV9 back-end</a> + <a name="arm-be">Known problems with the ARM 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> -<li>The SparcV9 backend is slated to be removed before the LLVM 1.8 - release.</li> +<li>The ARM backend is currently in early development stages, it is not +ready for production use.</li> </ul> </div> @@ -768,7 +683,7 @@ src="http://www.w3.org/Icons/valid-html401"; alt="Valid HTML 4.01!" /></a> <a href="http://llvm.org/";>The LLVM Compiler Infrastructure</a><br> - Last modified: $Date: 2006/04/20 04:24:28 $ + Last modified: $Date: 2006/08/08 17:27:28 $ </address> </body> _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
