Update the docs of the cost model.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171016 91177308-0d34-0410-b5e6-96231b3b80d8
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Nadav Rotem 2012-12-24 05:51:12 +00:00
parent 85e910fe5c
commit 99b7a99376

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//===----------------------------------------------------------------------===//
//
// This file defines the cost model analysis. It provides a very basic cost
// estimation for LLVM-IR. The cost result can be thought of as cycles, but it
// is really unit-less. The estimated cost is ment to be used for comparing
// alternatives.
// estimation for LLVM-IR. This analysis uses the services of the codegen
// to approximate the cost of any IR instruction when lowered to machine
// instructions. The cost results are unit-less and the cost number represents
// the throughput of the machine assuming that all loads hit the cache, all
// branches are predicted, etc. The cost numbers can be added in order to
// compare two or more transformation alternatives.
//
//===----------------------------------------------------------------------===//