From df4381b578b291e1d1044f29ce4720b16ad0b12c Mon Sep 17 00:00:00 2001 From: Nadav Rotem Date: Mon, 8 Apr 2013 21:34:49 +0000 Subject: [PATCH] Update the docs about the fact that the loop vectorizer is enabled by default for -O3. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179060 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/Vectorizers.rst | 13 ++++--------- 1 file changed, 4 insertions(+), 9 deletions(-) diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index e2d3667bc11..2c5604496b3 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 ^^^^^^^^^^^^^^^^^^