Julia level SROA ignores swapfield and replacefield

[gbaraldi]

I'm not sure if this can cause correctness issues, but we might be losing optimizations because of this.

julia/base/compiler/ssair/passes.jl

Line 1230 in 675e30a

# check whether this statement is `getfield` / `setfield!` (or other "interesting" statement)

[topolarity]

Not a soundness problem, since these count as an "escaping" usage:

julia/base/compiler/ssair/passes.jl

Lines 1671 to 1674 in 675e30a

	# Check if there are any uses we did not account for. If so, the variable
	# escapes and we cannot eliminate the allocation. This works, because we're guaranteed
	# not to include any intermediaries that have dead uses. As a result, missing uses will only ever
	# show up in the nuses_total count.

But still worth fixing.

[gbaraldi]

They are as escaping as setfield! (and kind of behave very much like it) with swap just being get + set.

[vtjnash]

There is not usually any loss of optimization, since generally the value already "escaped" to another thread anyways