[llvm] r179060 - Update the docs about the fact that the loop vectorizer is enabled by default for -O3.
Nadav Rotem
nrotem at apple.com
Mon Apr 8 14:34:50 PDT 2013
Author: nadav
Date: Mon Apr 8 16:34:49 2013
New Revision: 179060
URL: http://llvm.org/viewvc/llvm-project?rev=179060&view=rev
Log:
Update the docs about the fact that the loop vectorizer is enabled by default for -O3.
Modified:
llvm/trunk/docs/Vectorizers.rst
Modified: llvm/trunk/docs/Vectorizers.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/Vectorizers.rst?rev=179060&r1=179059&r2=179060&view=diff
==============================================================================
--- llvm/trunk/docs/Vectorizers.rst (original)
+++ llvm/trunk/docs/Vectorizers.rst Mon Apr 8 16:34:49 2013
@@ -21,19 +21,14 @@ The Loop Vectorizer
Usage
-----
-LLVM's Loop Vectorizer is now available and will be useful for many people.
-It is not enabled by default, but can be enabled through clang using the
-command line flag:
+LLVM's Loop Vectorizer is now enabled by default for -O3.
+The vectorizer can be disabled using the command line:
.. code-block:: console
- $ clang -fvectorize -O3 file.c
+ $ clang ... -fno-vectorize file.c
-If the ``-fvectorize`` flag is used then the loop vectorizer will be enabled
-when running with ``-O3``, ``-O2``. When ``-Os`` is used, the loop vectorizer
-will only vectorize loops that do not require a major increase in code size.
-
-We plan to enable the Loop Vectorizer by default as part of the LLVM 3.3 release.
+At this point the loop vectorizer is only enabled for -O3, and will not work for -O2 or -Os.
Command line flags
^^^^^^^^^^^^^^^^^^
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