[llvm] [SimplifyCFG] Switch to use `paramHasNonNullAttr` (PR #125383)

[Nikita Popov via llvm-commits]

https://github.com/nikic commented:

It looks like this adds some measurable overhead: https://llvm-compile-time-tracker.com/compare.php?from=2a3afa2feb90844ad0f8b0bc57663e2aec06cd0a&to=5b59246712a5c9446a526503818b7f86b824f03c&stat=instructions:u

Can you try changing the check in paramHasNonNullAttr to only use paramHasAttr instead of getParamDereferenceableBytes? This should be a more efficient way to check for non-zero dereferenceable bytes.

https://github.com/llvm/llvm-project/pull/125383