ee0bf64722
`(A * -2**C) + B --> B - (A << C)` https://alive2.llvm.org/ce/z/A6BWkf This inverts what Negator was doing before: D134310 / 0f32a5dea0e9 Analysis and codegen are generally better without multiply, so we should favor this form even if we trade add for sub (because those are generally equivalent cost operations).