[X86] Use a shift plus an lea for multiplying by a constant that is a power of 2 plus 2/4/8.

The LEA allows us to combine an add and the multiply by 2/4/8 together so we just need a shift for the larger power of 2.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337875 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed