[llvm] [ConstraintElim] Do not allow overflows in `Decomposition` (PR #140541)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=7e14161f49b32387988cf9d937bbfaa27d0fbdd5&to=854df22efb6c18b88e29f23def8c3b3643083ba7&stat=instructions:u

https://github.com/llvm/llvm-project/pull/140541