This casued miscompiles of switches, see comments on the code review.
> This extends `optimizeCompareInstr` to re-use previous comparison
> results if the previous comparison was with an immediate that was 1
> bigger or smaller. Example:
>
> CMP x, 13
> ...
> CMP x, 12 ; can be removed if we change the SETg
> SETg ... ; x > 12 changed to `SETge` (x >= 13) removing CMP
>
> Motivation: This often happens because SelectionDAG canonicalization
> tends to add/subtract 1 often when optimizing for fallthrough blocks.
> Example for `x > C` the fallthrough optimization switches true/false
> blocks with `!(x > C)` --> `x <= C` and canonicalization turns this into
> `x < C + 1`.
>
> Differential Revision: https://reviews.llvm.org/D110867
This reverts commit e2c7ee0743592e39274e28dbe0d0c213ba342317.
a2a58d91e8