| ========================= |
| LLVM 11.0.0 Release Notes |
| ========================= |
| |
| .. contents:: |
| :local: |
| |
| .. warning:: |
| These are in-progress notes for the upcoming LLVM 11 release. |
| Release notes for previous releases can be found on |
| `the Download Page <https://releases.llvm.org/download.html>`_. |
| |
| |
| Introduction |
| ============ |
| |
| This document contains the release notes for the LLVM Compiler Infrastructure, |
| release 11.0.0. Here we describe the status of LLVM, including major improvements |
| from the previous release, improvements in various subprojects of LLVM, and |
| some of the current users of the code. All LLVM releases may be downloaded |
| from the `LLVM releases web site <https://llvm.org/releases/>`_. |
| |
| For more information about LLVM, including information about the latest |
| release, please check out the `main LLVM web site <https://llvm.org/>`_. If you |
| have questions or comments, the `LLVM Developer's Mailing List |
| <https://lists.llvm.org/mailman/listinfo/llvm-dev>`_ is a good place to send |
| them. |
| |
| Note that if you are reading this file from a Git checkout or the main |
| LLVM web page, this document applies to the *next* release, not the current |
| one. To see the release notes for a specific release, please see the `releases |
| page <https://llvm.org/releases/>`_. |
| |
| Non-comprehensive list of changes in this release |
| ================================================= |
| .. NOTE |
| For small 1-3 sentence descriptions, just add an entry at the end of |
| this list. If your description won't fit comfortably in one bullet |
| point (e.g. maybe you would like to give an example of the |
| functionality, or simply have a lot to talk about), see the `NOTE` below |
| for adding a new subsection. |
| |
| * ... |
| |
| |
| .. NOTE |
| If you would like to document a larger change, then you can add a |
| subsection about it right here. You can copy the following boilerplate |
| and un-indent it (the indentation causes it to be inside this comment). |
| |
| Special New Feature |
| ------------------- |
| |
| Makes programs 10x faster by doing Special New Thing. |
| |
| |
| Changes to the LLVM IR |
| ---------------------- |
| |
| * The callsite attribute `vector-function-abi-variant |
| <https://llvm.org/docs/LangRef.html#call-site-attributes>`_ has been |
| added to describe the mapping between scalar functions and vector |
| functions, to enable vectorization of call sites. The information |
| provided by the attribute is interfaced via the API provided by the |
| ``VFDatabase`` class. |
| |
| * `dereferenceable` attributes and metadata on pointers no longer imply |
| anything about the alignment of the pointer in question. Previously, some |
| optimizations would make assumptions based on the type of the pointer. This |
| behavior was undocumented. To preserve optimizations, frontends may need to |
| be updated to generate appropriate `align` attributes and metadata. |
| |
| * The DIModule metadata is extended to contain file and line number |
| information. This information is used to represent Fortran modules debug |
| info at IR level. |
| |
| Changes to building LLVM |
| ------------------------ |
| |
| Changes to the ARM Backend |
| -------------------------- |
| |
| During this release ... |
| |
| * Implemented C-language intrinsics for the full Arm v8.1-M MVE instruction |
| set. ``<arm_mve.h>`` now supports the complete API defined in the Arm C |
| Language Extensions. |
| |
| * Added support for assembly for the optional Custom Datapath Extension (CDE) |
| for Arm M-profile targets. |
| |
| * Implemented C-language intrinsics ``<arm_cde.h>`` for the CDE instruction set. |
| |
| Changes to the MIPS Target |
| -------------------------- |
| |
| During this release ... |
| |
| |
| Changes to the PowerPC Target |
| ----------------------------- |
| |
| During this release ... |
| |
| Changes to the X86 Target |
| ------------------------- |
| |
| During this release ... |
| |
| |
| * Functions with the probe-stack attribute set to "inline-asm" are now protected |
| against stack clash without the need of a third-party probing function and |
| with limited impact on performance. |
| * -x86-enable-old-knl-abi command line switch has been removed. v32i16/v64i8 |
| vectors are always passed in ZMM register when avx512f is enabled and avx512bw |
| is disabled. |
| * Vectors larger than 512 bits with i16 or i8 elements will be passed in |
| multiple ZMM registers when avx512f is enabled. Previously this required |
| avx512bw otherwise they would split into multiple YMM registers. This means |
| vXi16/vXi8 vectors are consistently treated the same as |
| vXi32/vXi64/vXf64/vXf32 vectors of the same total width. |
| |
| Changes to the AMDGPU Target |
| ----------------------------- |
| |
| * The backend default denormal handling mode has been switched to on |
| for all targets for all compute function types. Frontends wishing to |
| retain the old behavior should explicitly request f32 denormal |
| flushing. |
| |
| Changes to the AVR Target |
| ----------------------------- |
| |
| * Moved from an experimental backend to an official backend. AVR support is now |
| included by default in all LLVM builds and releases and is available under |
| the "avr-unknown-unknown" target triple. |
| |
| Changes to the WebAssembly Target |
| --------------------------------- |
| |
| During this release ... |
| |
| |
| Changes to the OCaml bindings |
| ----------------------------- |
| |
| |
| |
| Changes to the C API |
| -------------------- |
| |
| |
| Changes to the Go bindings |
| -------------------------- |
| |
| |
| Changes to the DAG infrastructure |
| --------------------------------- |
| |
| |
| Changes to the Debug Info |
| --------------------------------- |
| |
| * LLVM now supports the debug entry values (DW_OP_entry_value) production for |
| the x86, ARM, and AArch64 targets by default. Other targets can use |
| the utility by using the experimental option ("-debug-entry-values"). |
| This is a debug info feature that allows debuggers to recover the value of |
| optimized-out parameters by going up a stack frame and interpreting the values |
| passed to the callee. The feature improves the debugging user experience when |
| debugging optimized code. |
| |
| Changes to the LLVM tools |
| --------------------------------- |
| |
| * Added an option (--show-section-sizes) to llvm-dwarfdump to show the sizes |
| of all debug sections within a file. |
| |
| Changes to LLDB |
| =============== |
| |
| External Open Source Projects Using LLVM 11 |
| =========================================== |
| |
| * A project... |
| |
| |
| Additional Information |
| ====================== |
| |
| A wide variety of additional information is available on the `LLVM web page |
| <https://llvm.org/>`_, in particular in the `documentation |
| <https://llvm.org/docs/>`_ section. The web page also contains versions of the |
| API documentation which is up-to-date with the Git version of the source |
| code. You can access versions of these documents specific to this release by |
| going into the ``llvm/docs/`` directory in the LLVM tree. |
| |
| If you have any questions or comments about LLVM, please feel free to contact |
| us via the `mailing lists <https://llvm.org/docs/#mailing-lists>`_. |