Just a heads up here… when compiling with Xcode 13 I experienced performance issues that looked very much like a denormals issue (processing time increasing dramatically for my FX algorithms as audio level tapers out) - I confirmed with some profiling code that for example my Reverb algorithm started to take over 10X longer than usual to process each block.
(Note that my audio processing code main process block uses the JUCE function to disable denormalised numbers support ‘disableDenormalisedNumberSupport()’ and I even confirmed it is being entered correctly and used the ‘areDenormalsDisabled()’ function to confirm it is set)
Interestingly this issue only appeared in release mode builds - and went away when I downgraded to Xcode 12.5.
I’m not sure if there is something different about the C++ compiler in Xcode13, but perhaps it was not correctly setting register settings (testing on Intel Mac btw).
I’m not sure how I could confirm registers are set correctly, and sorry that I don’t know if the compiler version is different in Xcode13 - I spent a week just debugging my code as I thought I’d introduced an issue… but a ‘quick’ (download took ages) download and the issue went away with Xcode 12.5 and exact same code base - not in a hurry to update again.