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| author | Nadav Rotem <nrotem@apple.com> | 2013-01-03 01:56:33 +0000 |
|---|---|---|
| committer | Nadav Rotem <nrotem@apple.com> | 2013-01-03 01:56:33 +0000 |
| commit | 43f3928c79c7c41ebd616cf42285853da6159e80 (patch) | |
| tree | 93ffa9412426e2117f57b68de8d2a530a2a26685 /docs/Vectorizers.rst | |
| parent | 22bd64173981bf1251c4b3bfc684207340534ba3 (diff) | |
| download | external_llvm-43f3928c79c7c41ebd616cf42285853da6159e80.zip external_llvm-43f3928c79c7c41ebd616cf42285853da6159e80.tar.gz external_llvm-43f3928c79c7c41ebd616cf42285853da6159e80.tar.bz2 | |
Reformat the rst text.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171449 91177308-0d34-0410-b5e6-96231b3b80d8
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| -rw-r--r-- | docs/Vectorizers.rst | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index b4c5458..d679ca4 100644 --- a/docs/Vectorizers.rst +++ b/docs/Vectorizers.rst @@ -208,15 +208,14 @@ Partial unrolling during vectorization ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Modern processors feature multiple execution units, and only programs that contain a -high degree of parallelism can fully utilize the entire width of the machine. - +high degree of parallelism can fully utilize the entire width of the machine. The Loop Vectorizer increases the instruction level parallelism (ILP) by performing partial-unrolling of loops. In the example below the entire array is accumulated into the variable 'sum'. -This is inefficient because only a single 'adder' can be used by the processor. +This is inefficient because only a single execution port can be used by the processor. By unrolling the code the Loop Vectorizer allows two or more execution ports -to be used. +to be used simultaneously. .. code-block:: c++ |