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| author | Reid Kleckner <reid@kleckner.net> | 2014-04-18 21:19:06 +0000 |
|---|---|---|
| committer | Reid Kleckner <reid@kleckner.net> | 2014-04-18 21:19:06 +0000 |
| commit | ed5604850a0dbb79dd41a8d950b776e553992fa3 (patch) | |
| tree | 6d27bd17db66770984d3d1611035ccca040c9df0 /docs/Passes.rst | |
| parent | 904f8dcaa489f5d58c3fd43adc912f00a1dd152d (diff) | |
| download | llvm-ed5604850a0dbb79dd41a8d950b776e553992fa3.tar.gz llvm-ed5604850a0dbb79dd41a8d950b776e553992fa3.tar.bz2 llvm-ed5604850a0dbb79dd41a8d950b776e553992fa3.tar.xz | |
Remove -simplify-libcalls pass form Passes documentation
This pass was removed in r184459.
Also added note that the InstCombine pass does library call
simplification.
Patch slightly modified from one by Daniel Liew
<daniel.liew@imperial.ac.uk>!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206650 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/Passes.rst')
| -rw-r--r-- | docs/Passes.rst | 19 |
1 files changed, 10 insertions, 9 deletions
diff --git a/docs/Passes.rst b/docs/Passes.rst index b2703b7c03..b51829d3a3 100644 --- a/docs/Passes.rst +++ b/docs/Passes.rst @@ -540,6 +540,8 @@ instructions that are obviously dead. A trivial dead store elimination that only considers basic-block local redundant stores. +.. _passes-functionattrs: + ``-functionattrs``: Deduce function attributes ---------------------------------------------- @@ -648,7 +650,7 @@ program, and is used for a wide variety of program transformations. ------------------------------------------------ Combine instructions to form fewer, simple instructions. This pass does not -modify the CFG This pass is where algebraic simplification happens. +modify the CFG. This pass is where algebraic simplification happens. This pass combines things like: @@ -681,6 +683,13 @@ program: shifts. #. … etc. +This pass can also simplify calls to specific well-known function calls (e.g. +runtime library functions). For example, a call ``exit(3)`` that occurs within +the ``main()`` function can be transformed into simply ``return 3``. Whether or +not library calls are simplified is controlled by the +:ref:`-functionattrs <passes-functionattrs>` pass and LLVM's knowledge of +library calls on different targets. + ``-internalize``: Internalize Global Symbols -------------------------------------------- @@ -1011,14 +1020,6 @@ as: Note that this pass has a habit of making definitions be dead. It is a good idea to run a :ref:`DCE <passes-dce>` pass sometime after running this pass. -``-simplify-libcalls``: Simplify well-known library calls ---------------------------------------------------------- - -Applies a variety of small optimizations for calls to specific well-known -function calls (e.g. runtime library functions). For example, a call -``exit(3)`` that occurs within the ``main()`` function can be transformed into -simply ``return 3``. - .. _passes-simplifycfg: ``-simplifycfg``: Simplify the CFG |