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Diffstat (limited to 'docs/Vectorizers.rst')
| -rw-r--r-- | docs/Vectorizers.rst | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index e2d3667bc1..2c5604496b 100644 --- a/docs/Vectorizers.rst +++ b/docs/Vectorizers.rst @@ -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 ^^^^^^^^^^^^^^^^^^ |