[llvm] [EarlyIfConversion] Limit critical-path growth for strongly biased branches (PR #228709)

[Jonathan Cohen via llvm-commits]

=?utf-8?q?Dávid_Bolvanský?= <david.bolvansky at gmail.com>,
=?utf-8?q?Dávid_Bolvanský?= <david.bolvansky at gmail.com>,
=?utf-8?q?Dávid_Bolvanský?= <david.bolvansky at gmail.com>,
=?utf-8?q?Dávid_Bolvanský?= <david.bolvansky at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/228709 at github.com>


jcohen-apple wrote:

Thanks for the PR!

Can you share any results from other workloads or benchmarks? I can understand why you would maybe want to avoid converting predictable branches (I implemented a similar check to this on the data-dependent branch analysis), but not that branch probability != mispredict probability. A branch could be heavily biased or even slightly biased but still perfectly predictable if it follows a pattern which the branch predictor can learn. 

https://github.com/llvm/llvm-project/pull/228709