[X86] Prefer rotate by 1 over rotate by imm

Summary:
Rotate by 1 is translated to 1 micro-op, while rotate with imm8 is translated to 2 micro-ops.

Fixes pr30644.

Reviewers: delena, igorb, craig.topper, spatel, RKSimon

Differential Revision: https://reviews.llvm.org/D25399

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@283758 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed