[X86][SSE] Add cost model values for CTPOP of vectors

This patch adds costs for the vectorized implementations of CTPOP, the default values were seriously underestimating the cost of these and was encouraging vectorization on targets where serialized use of POPCNT would be much better.

Differential Revision: https://reviews.llvm.org/D22456

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@276104 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed