C++: Small simplification

[igfoo]

Removes an unnecessary intermediate variable

[Copilot]

Pull request overview

This PR simplifies the implementation of a helper predicate in the C++ control-flow guard reasoning library by removing an exists wrapper and directly delegating to compares_lt with the transformed offset.

Changes:

• Simplify compares_ge to a direct call to compares_lt(..., 1 - k, ...).

[jketema]

Could you run some DCA on this?

[jketema]

I'm not sure if that DCA run is a fluke, or whether it points to a join-order problem with this change, but there's a significant slowdown on Wireshark (with a very large standard deviation).

[igfoo]

That run had

Analysis time, per source
source                  a_m     a_std   b_m     b_std   diff    relative
wireshark__wireshark    1445    13.89   1656    176     211     0.146

The second run has

source                  a_m     a_std   b_m     b_std   diff    relative
wireshark__wireshark    1462    0       1429    0       -33     -0.0226

so I think it was a fluke. I would be surprised if the compiled code was different, anyway.

[jketema]

LGTM