From: Nadav Rotem Date: Thu, 3 Jan 2013 01:56:33 +0000 (+0000) Subject: Reformat the rst text. X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=43f3928c79c7c41ebd616cf42285853da6159e80;p=oota-llvm.git Reformat the rst text. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171449 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index b4c5458953b..d679ca49540 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++