inference: don't forget to add backedge for effect-free frame (#45017)
Now our abstract interpretation system caches two separate lattice
properties return type and call effects, and the previous optimization
to avoid adding backedge for a frame whose return type is `Any` turns
out to be insufficient -- now we also need to make sure that the
inferred effects don't provide any useful IPO information.
Example:
```julia
julia> const CONST_DICT = let d = Dict()
for c in 'A':'z'
push!(d, c => Int(c))
end
d
end;
julia> Base.@assume_effects :total_may_throw getcharid(c) = CONST_DICT[c];
julia> @noinline callf(f, args...) = f(args...);
julia> function entry_to_be_invalidated(c)
return callf(getcharid, c)
end;
julia> @test Base.infer_effects((Char,)) do x
entry_to_be_invalidated(x)
end |> Core.Compiler.is_concrete_eval_eligible
Test Passed
julia> @test fully_eliminated(; retval=97) do
entry_to_be_invalidated('a')
end
Test Passed
julia> getcharid(c) = CONST_DICT[c]; # now this is not eligible for concrete evaluation
julia> @test Base.infer_effects((Char,)) do x
entry_to_be_invalidated(x)
end |> !Core.Compiler.is_concrete_eval_eligible
Test Failed at REPL[10]:1
Expression: Base.infer_effects((Char,)) do x
entry_to_be_invalidated(x)
end |> !(Core.Compiler.is_concrete_eval_eligible)
ERROR: There was an error during testing
julia> @test !fully_eliminated() do
entry_to_be_invalidated('a')
end
Test Failed at REPL[11]:1
Expression: !(fully_eliminated() do
entry_to_be_invalidated('a')
end)
ERROR: There was an error during testing
```
julia
4c723434 - inference: don't forget to add backedge for effect-free frame (#45017)
