Follow-up #46651 - Fix a slight logic bug

Found while testing bigger examples.

Author: Keno

base/compiler/ssair/passes.jl

@@ -1148,8 +1148,8 @@ function try_resolve_finalizer!(ir::IRCode, idx::Int, finalizer_idx::Int, defuse
     function note_block_use!(usebb::Int, useidx::Int)
         new_bb_insert_block = nearest_common_dominator(get!(lazypostdomtree),
             bb_insert_block, usebb)
-        if new_bb_insert_block == usebb
-            if usebb == bb_insert_block
+        if new_bb_insert_block == bb_insert_block == usebb
+            if bb_insert_idx !== nothing
                 bb_insert_idx = max(bb_insert_idx, useidx)
             else
                 bb_insert_idx = useidx
@@ -1172,7 +1172,7 @@ function try_resolve_finalizer!(ir::IRCode, idx::Int, finalizer_idx::Int, defuse
         bb = block_for_inst(ir, duidx)
         # Not reachable from finalizer registration - we're ok
         bb ∉ blocks && return true
-        note_block_use!(bb, idx)
+        note_block_use!(bb, duidx)
         if dominates(domtree, finalizer_bb, bb)
             return true
         else

test/compiler/inline.jl

@@ -1537,6 +1537,34 @@ let
     @test get_finalization_count() == 1000
 end
 
+
+function cfg_finalization7(io)
+    for i = -999:1000
+        o = DoAllocWithField(0)
+        o.x = 0
+        if i == 1000
+            o.x = i # with `setfield!`
+        end
+        o.x = i
+        if i == 999
+            o.x = i
+        end
+        o.x = 0
+        if i == 1000
+            o.x = i
+        end
+    end
+end
+let src = code_typed1(cfg_finalization7, (IO,))
+    @test count(isinvoke(:add_finalization_count!), src.code) == 1
+end
+let
+    init_finalization_count!()
+    cfg_finalization7(IOBuffer())
+    @test get_finalization_count() == 1000
+end
+
+
 # optimize `[push!|pushfirst!](::Vector{Any}, x...)`
 @testset "optimize `$f(::Vector{Any}, x...)`" for f = Any[push!, pushfirst!]
     @eval begin