Optimize Sub operations based upon the loop induction variable

[vezenovm]

Problem

In #6910 we started hoisting add/mul operations based upon the outer loop's induction variable. While in #7344 we are adding further optimizations to transform checked operations to unchecked based upon the induction variable.

For simplicity in those initial PRs, sub operations were not included in the above optimizations. Sub overflows depend on if the induction variable is on the lhs or the rhs (e.g. if it is the rhs we should check the induction variable's upper bound but if it is the lhs we should check the lower bound).

Happy Case

Sub operations that do not overflow when using a given induction variable should be optimized either through hoisting or being transformed to an unchecked operation.

Workaround

None

Workaround Description

The compiler needs to add this optimization for it to be applied.

Additional Context

No response

Project Impact

Blocker

Blocker Context

No response

Would you like to submit a PR for this Issue?

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Support Needs

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