[stdlib] loading a reference can’t use loadUnaligned

[glessard]

Change a mistaken use of loadUnaligned to just load. The source pointer must be aligned for a reference, since it's either typed as an Any or an AnyObject in the Objective-C runtime interface.

This is a fix for the issue mentioned in #78452 (comment)

[glessard]

@swift-ci please benchmark

[glessard]

@swift-ci please smoke test

[Catfish-Man]

Looks good to me assuming it does the trick. Thanks!

[glessard]

@swift-ci please benchmark

[glessard]

Regarding the benchmarking failure: it's running the benchmarks off the existing main branch that's failing. We tested the benchmarks after the change, and they ran. We don't have a way to ask CI to only run the benchmarks after the fix.

[eeckstein]

@glessard @Catfish-Man x86 benchmarks still crash in the same benchmark. Both the Onone and O benchmarks:

* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x158828)
  * frame #0: 0x00007ff803823005 libobjc.A.dylib`objc_retain + 37
    frame #1: 0x000000010022826e Benchmark_Onone-x86_64-apple-macosx13.0`closure #1 in run_BridgedNSArrayBufferAccess($0=105553128736064 values (0x10ad33e00)) at ObjectiveCBridging.swift:831:11

Is this the same problem?

[Catfish-Man]

Seems unlikely but could still be related in some way

[glessard]

The issue mentioned by @eeckstein above is fixed by #78647