Arnold Schwaighofer 2537f3c659 X86 cost model: Differentiate cost for vector shifts of constants
SSE2 has efficient support for shifts by a scalar. My previous change of making
shifts expensive did not take this into account marking all shifts as expensive.
This would prevent vectorization from happening where it is actually beneficial.

With this change we differentiate between shifts of constants and other shifts.

radar://13576547

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178808 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-04 23:26:24 +00:00
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