[x86] fix cost model inaccuracy for vector memory ops
The irony of this patch is that one CPU that is affected is AMD Jaguar, and Jaguar
has a completely double-pumped AVX implementation. But getting the cost model to
reflect that is a much bigger problem. The small goal here is simply to improve on
the lie that !AVX2 == SandyBridge.
Differential Revision: http://reviews.llvm.org/D18000
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263069 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed