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diff --git a/docs/ReleaseNotes.html b/docs/ReleaseNotes.html index 2622a496ab..c8fc2ab206 100644 --- a/docs/ReleaseNotes.html +++ b/docs/ReleaseNotes.html @@ -93,13 +93,14 @@ analysis tools or source-to-source translators.</p> <div class="doc_text"> -<p>Some of the most noticable improvements this release have been in the -optimizer, speeding it up and making it more aggressive</p> +<p>Some of the most noticable feature improvements this release have been in the +optimizer, speeding it up and making it more aggressive. For example:</p> <ul> <li>Owen Anderson wrote the new MemoryDependenceAnalysis pass, which provides - a lazy, caching layer on top of alias analysis. He then used it to rewrite + a lazy, caching layer on top of <a href="AliasAnalysis.html"> + AliasAnalysis</a>. He then used it to rewrite DeadStoreElimination which resulted in significantly better compile time in common cases, </li> <li>Owen implemented the new GVN pass, which is also based on @@ -110,9 +111,11 @@ optimizer, speeding it up and making it more aggressive</p> shares some details with the new GVN pass. It is still in need of compile time tuning, and is not turned on by default.</li> <li>Devang merged ETForest and DomTree into a single easier to use data -structure.</li> + structure. This makes it more obvious which datastructure to choose + (because there is only one) and makes the compiler more memory and time + efficient (less stuff to keep up-to-date).</li> <li>Nick Lewycky improved loop trip count analysis to handle many more common -cases.</li> + cases.</li> </ul> @@ -125,33 +128,43 @@ cases.</li> <div class="doc_text"> +<p>One of the main focuses of this release was performance tuning and bug + fixing. In addition to these, several new major changes occurred:</p> + <ul> -<li>Dale finished up the Tail Merging optimization in the code generator, -enabling it by default. This produces smaller code that is also faster in some -cases.</li> +<li>Dale finished up the Tail Merging optimization in the code generator, and + enabled it by default. This produces smaller code that is also faster in + some cases.</li> + +<li>Christopher Lamb implemented support for virtual register sub-registers, + which can be used to better model many forms of subregisters. As an example + use, he modified the X86 backend to use this to model truncates and + extends more accurately (leading to better code).</li> <li>Dan Gohman changed the way we represent vectors before legalization, -significantly simplifying the SelectionDAG representation for these and making -the code generator faster for vector code.</li> + significantly simplifying the SelectionDAG representation for these and + making the code generator faster for vector code.</li> -<li>Evan remat rewrite (coalesced intervals + folding of remat'd loads) and -live intervals improvements.</li> +<li>Evan contributed a new target independent if-converter. While it is + target independent, at this point only the ARM backend uses it so far.</li> -<li>Dan Gohman contributed support for better alignment and volatility handling -in the code generator, and significantly enhanced alignment analysis for SSE -load/store instructions.</li> +<li>Evan rewrite the way the register allocator handles rematerialization, + allowing it to be much more effective on two-address targets like X86, + and taught it to fold loads away when possible (also a big win on X86).</li> -<li>Christopher Lamb virtual register sub-register support, better truncates and -extends on X86.</li> +<li>Dan Gohman contributed support for better alignment and volatility handling + in the code generator, and significantly enhanced alignment analysis for SSE + load/store instructions. With his changes, an insufficiently-aligned SSE + load instruction turns into <tt>movups</tt>, for example.</li> <li>Duraid Madina contributed a new "bigblock" register allocator, and Roman -Levenstein contributed several big improvements. BigBlock is optimized for code -that uses very large basic blocks. It is slightly slower than the "local" -allocator, but produces much better code.</li> + Levenstein contributed several big improvements. BigBlock is optimized for + code that uses very large basic blocks. It is slightly slower than the + "local" allocator, but produces much better code.</li> <li>David Greene refactored the register allocator to split coalescing out from -allocation, making coalescers pluggable.</li> + allocation, making coalescers pluggable.</li> </ul> @@ -168,13 +181,19 @@ allocation, making coalescers pluggable.</li> </p> <ul> -<li>Bruno Cardoso Lopes contributed initial MIPS support.</li> -<li>Bill Wendling added SSSE3 support.</li> -<li>New Target independent if converter, ARM uses it so far</li> +<li>Bruno Cardoso Lopes contributed initial MIPS support. It is sufficient to + run many small programs, but is still incomplete and is not yet + fully performant.</li> + +<li>Bill Wendling added SSSE3 support to the X86 backend.</li> + <li>Nicholas Geoffray contributed improved linux/ppc ABI and JIT support.</li> + <li>Dale Johannesen rewrote handling of 32-bit float values in the X86 backend -when using the floating point stack, fixing several nasty bugs.</li> -<li>Dan contributed rematerialization support for the X86 backend.</li> + when using the floating point stack, fixing several nasty bugs.</li> + +<li>Dan contributed rematerialization support for the X86 backend, in addition + to several X86-specific micro optimizations.</li> </ul> </div> @@ -190,22 +209,28 @@ when using the floating point stack, fixing several nasty bugs.</li> </p> <ul> -<li>Duncan and Anton exception handling in llvm-gcc 4.0/4.2</li> +<li>Duncan and Anton made significant progress chasing down a number of problems + with C++ Zero-Cost exception handling in llvm-gcc 4.0 and 4.2. It is now at + the point where it "just works" on linux/x86-32 and has partial support on + other targets.</li> -<li>Devang and Duncan: Bitfields, pragma pack</li> +<li>Devang and Duncan fixed a huge number of bugs relating to bitfields, pragma + pack, and variable sized fields in structures.</li> -<li>Tanya implemented support for __attribute__((noinline)) in llvm-gcc, and -added support for generic variable annotations which are propagated into the -LLVM IR, e.g. "<tt>int X __attribute__((annotate("myproperty")));</tt>".</li> +<li>Tanya implemented support for <tt>__attribute__((noinline))</tt> in + llvm-gcc, and added support for generic variable annotations which are + propagated into the LLVM IR, e.g. + "<tt>int X __attribute__((annotate("myproperty")));</tt>".</li> <li>Sheng Zhou and Christopher Lamb implemented alias analysis support for -'restrict' arguments to functions.</li> +"restrict" pointer arguments to functions.</li> -<li>Duncan contributed support for trampolines (pointers to nested functions), -currently only supported on x86 target.</li> +<li>Duncan contributed support for trampolines (taking the address of a nested + functions), currently this is only supported in the x86 target.</li> -<li> Lauro Ramos Venancio contributed support to encode alignment info in -load and store instructions.</li> +<li>Lauro Ramos Venancio contributed support to encode alignment info in + load and store instructions, the foundation for other alignment-related + work.</li> </ul> </div> @@ -221,15 +246,22 @@ load and store instructions.</li> </p> <ul> -<li>Neil Booth APFloat, foundation for long double support that will be wrapped -up in 2.2. Dale contributed most of long double support, will be enabled in -2.2.</li> +<li>Neil Booth contributed a new "APFloat" class, which ensures that floating + point representation and constant folding is not dependent on the host + architecture that builds the application. This support is the foundation + for "long double" support that will be wrapped up in LLVM 2.2.</li> + +<li>Based on the APFloat class, Dale redesigned the internals of the ConstantFP + class and has been working on extending the core and optimizer components to + support various target-specific 'long double's. We expect this work to be + completed in LLVM 2.2.</li> -<li>LLVM now provides an LLVMBuilder class which makes it significantly easier -to create LLVM IR instructions.</li> +<li>LLVM now provides an LLVMBuilder class, which makes it significantly easier + to create LLVM IR instructions.</li> <li>Reid contributed support for intrinsics that take arbitrary integer typed -arguments, Dan Gohman and Chandler extended it to support FP and vectors.</li> + arguments. Dan Gohman and Chandler extended it to support arbitrary + floating point arguments and vectors.</li> </ul> </div> @@ -244,10 +276,13 @@ arguments, Dan Gohman and Chandler extended it to support FP and vectors.</li> </p> <ul> -<li>BrainF frontend by Sterling Stein.</li> +<li>Sterling Stein contributed a new BrainF frontend, located in llvm/examples. + This shows a some of the more modern APIs for building a front-end, and + demonstrates JIT compiler support.</li> -<li>David Green contributed a new --enable-expensive-checks configure option -which enables STL checking, and fixed several bugs exposed by it.</li> +<li>David Green contributed a new <tt>--enable-expensive-checks</tt> configure + option which enables STL checking, and fixed several bugs exposed by + it.</li> </ul> </div> |