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| author | Nadav Rotem <nrotem@apple.com> | 2013-08-05 04:27:34 +0000 |
|---|---|---|
| committer | Nadav Rotem <nrotem@apple.com> | 2013-08-05 04:27:34 +0000 |
| commit | 055028f6c805b089d10984ec691aa637cf21dc42 (patch) | |
| tree | 2069ec8659184f4d6479c707b702029994ec5fe6 /docs/Vectorizers.rst | |
| parent | 25278aa26fa498e41830946b2138f01473269df2 (diff) | |
| download | external_llvm-055028f6c805b089d10984ec691aa637cf21dc42.zip external_llvm-055028f6c805b089d10984ec691aa637cf21dc42.tar.gz external_llvm-055028f6c805b089d10984ec691aa637cf21dc42.tar.bz2 | |
Update the docs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187713 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'docs/Vectorizers.rst')
| -rw-r--r-- | docs/Vectorizers.rst | 32 |
1 files changed, 6 insertions, 26 deletions
diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index 221fb29..61ebca2 100644 --- a/docs/Vectorizers.rst +++ b/docs/Vectorizers.rst @@ -13,6 +13,8 @@ The SLP vectorizer merges multiple scalars that are found in the code into vectors while the Loop Vectorizer widens instructions in loops to operate on multiple consecutive iterations. +Both the Loop Vectorizer and the SLP Vectorizer are enabled by default. + .. _loop-vectorizer: The Loop Vectorizer @@ -21,9 +23,8 @@ The Loop Vectorizer Usage ----- -LLVM's Loop Vectorizer is now enabled by default for -O3. -We plan to enable parts of the Loop Vectorizer on -O2 and -Os in future releases. -The vectorizer can be disabled using the command line: +The Loop Vectorizer is enabled by default, but it can be disabled +through clang using the command line flag: .. code-block:: console @@ -322,12 +323,12 @@ The SLP-vectorizer processes the code bottom-up, across basic blocks, in search Usage ------ -The SLP Vectorizer is not enabled by default, but it can be enabled +The SLP Vectorizer is enabled by default, but it can be disabled through clang using the command line flag: .. code-block:: console - $ clang -fslp-vectorize file.c + $ clang -fno-slp-vectorize file.c LLVM has a second basic block vectorization phase which is more compile-time intensive (The BB vectorizer). This optimization @@ -337,24 +338,3 @@ can be enabled through clang using the command line flag: $ clang -fslp-vectorize-aggressive file.c - -The SLP vectorizer is in early development stages but can already vectorize -and accelerate many programs in the LLVM test suite. - -======================= ============ -Benchmark Name Gain -======================= ============ -Misc/flops-7 -32.70% -Misc/matmul_f64_4x4 -23.23% -Olden/power -21.45% -Misc/flops-4 -14.90% -ASC_Sequoia/AMGmk -13.85% -TSVC/LoopRerolling-flt -11.76% -Misc/flops-6 -9.70% -Misc/flops-5 -8.54% -Misc/flops -8.12% -TSVC/NodeSplitting-dbl -6.96% -Misc-C++/sphereflake -6.74% -Ptrdist/yacr2 -6.31% -======================= ============ - |