avoid jl_arrayunset in dicts with bitstypes; add some more @inbounds (#30113)

* avoid jl_arrayunset in dicts with bitstypes; add some more @inbounds

* also skip jl_arrayunset for isbitsunion

* amend typo

Author: JeffBezanson

base/dict.jl

@@ -571,7 +571,7 @@ function getkey(h::Dict{K,V}, key, default) where V where K
 end
 
 function _pop!(h::Dict, index)
-    val = h.vals[index]
+    @inbounds val = h.vals[index]
     _delete!(h, index)
     return val
 end
@@ -619,10 +619,10 @@ function pop!(h::Dict)
     key => val
 end
 
-function _delete!(h::Dict, index)
-    h.slots[index] = 0x2
-    ccall(:jl_arrayunset, Cvoid, (Any, UInt), h.keys, index-1)
-    ccall(:jl_arrayunset, Cvoid, (Any, UInt), h.vals, index-1)
+function _delete!(h::Dict{K,V}, index) where {K,V}
+    @inbounds h.slots[index] = 0x2
+    isbitstype(K) || isbitsunion(K) || ccall(:jl_arrayunset, Cvoid, (Any, UInt), h.keys, index-1)
+    isbitstype(V) || isbitsunion(V) || ccall(:jl_arrayunset, Cvoid, (Any, UInt), h.vals, index-1)
     h.ndel += 1
     h.count -= 1
     h.age += 1