WIP: Warn if @code_typed, @code_warntype, etc. are showing inaccurate specialization#33142
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DilumAluthge wants to merge 1 commit intoJuliaLang:masterfrom
DilumAluthge:da/being-honest-about-specialization
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WIP: Warn if @code_typed, @code_warntype, etc. are showing inaccurate specialization#33142DilumAluthge wants to merge 1 commit intoJuliaLang:masterfrom DilumAluthge:da/being-honest-about-specialization
DilumAluthge wants to merge 1 commit intoJuliaLang:masterfrom
DilumAluthge:da/being-honest-about-specialization
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Here are some examples: julia> f1(x) = Base.typemax(x)
f1 (generic function with 1 method)
julia> @code_lowered f1(Int)
WARNING: I am lying to you.
CodeInfo(
1 ─ %1 = Base.typemax
│ %2 = (%1)(x)
└── return %2
)
julia> @code_typed f1(Int)
WARNING: I am lying to you.
CodeInfo(
1 ─ return 9223372036854775807
) => Int64
julia> @code_warntype f1(Int)
WARNING: I am lying to you.
Variables
#self#::Core.Compiler.Const(f1, false)
x::Core.Compiler.Const(Int64, false)
Body::Int64
1 ─ %1 = Base.typemax::Core.Compiler.Const(typemax, false)
│ %2 = (%1)(x)::Core.Compiler.Const(9223372036854775807, false)
└── return %2
julia> g(x) = x + x
g (generic function with 1 method)
julia> @code_lowered g(1)
CodeInfo(
1 ─ %1 = x + x
└── return %1
)
julia> @code_typed g(1)
CodeInfo(
1 ─ %1 = Base.add_int(x, x)::Int64
└── return %1
) => Int64
julia> @code_warntype g(1)
Variables
#self#::Core.Compiler.Const(g, false)
x::Int64
Body::Int64
1 ─ %1 = (x + x)::Int64
└── return %1
julia> foo(t::Type) = t
foo (generic function with 1 method)
julia> @code_lowered foo(Int)
WARNING: I am lying to you.
CodeInfo(
1 ─ return t
)
julia> @code_typed foo(Int)
WARNING: I am lying to you.
CodeInfo(
1 ─ return t
) => Type{Int64}
julia> @code_warntype foo(Int)
WARNING: I am lying to you.
Variables
#self#::Core.Compiler.Const(foo, false)
t::Core.Compiler.Const(Int64, false)
Body::Type{Int64}
1 ─ return t
julia> function foo2(t::Type)
x = ones(t, 10)
return sum(map(sin, x))
end
foo2 (generic function with 1 method)
julia> @code_lowered foo2(Int)
WARNING: I am lying to you.
CodeInfo(
1 ─ x = Main.ones(t, 10)
│ %2 = Main.map(Main.sin, x)
│ %3 = Main.sum(%2)
└── return %3
)
julia> @code_typed foo2(Int)
WARNING: I am lying to you.
CodeInfo(
1 ── %1 = $(Expr(:foreigncall, :(:jl_alloc_array_1d), Array{Int64,1}, svec(Any, Int64), 0, :(:ccall), Array{Int64,1}, 10, 10))::Array{Int64,1}
│ invoke Base.fill!(%1::Array{Int64,1}, 1::Int64)::Any
│ %3 = %new(Base.Generator{Array{Int64,1},typeof(sin)}, sin, %1)::Base.Generator{Array{Int64,1},typeof(sin)}
│ %4 = invoke Base._collect(%1::Array{Int64,1}, %3::Base.Generator{Array{Int64,1},typeof(sin)}, $(QuoteNode(Base.EltypeUnknown()))::Base.EltypeUnknown, $(QuoteNode(Base.HasShape{1}()))::Base.HasShape{1})::Array{Float64,1}
│ %5 = Base.identity::typeof(identity)
│ %6 = Base.add_sum::typeof(Base.add_sum)
│ %7 = Base.arraysize(%4, 1)::Int64
│ %8 = Base.slt_int(%7, 0)::Bool
│ %9 = Base.ifelse(%8, 0, %7)::Int64
│ %10 = Base.sub_int(%9, 0)::Int64
│ %11 = (%10 === 0)::Bool
└─── goto #3 if not %11
2 ── goto #11
3 ── %14 = (%10 === 1)::Bool
└─── goto #5 if not %14
4 ── %16 = Base.arrayref(false, %4, 1)::Float64
└─── goto #11
5 ── %18 = Base.slt_int(%10, 16)::Bool
└─── goto #10 if not %18
6 ── %20 = Base.arrayref(false, %4, 1)::Float64
│ %21 = Base.arrayref(false, %4, 2)::Float64
└─── %22 = Base.add_float(%20, %21)::Float64
7 ┄─ %23 = φ (#6 => 2, #8 => %29)::Int64
│ %24 = φ (#6 => %22, #8 => %31)::Float64
│ %25 = Base.slt_int(%9, 0)::Bool
│ %26 = Base.ifelse(%25, 0, %9)::Int64
│ %27 = Base.slt_int(%23, %26)::Bool
└─── goto #9 if not %27
8 ── %29 = Base.add_int(%23, 1)::Int64
│ %30 = Base.arrayref(false, %4, %29)::Float64
│ %31 = Base.add_float(%24, %30)::Float64
└─── goto #7
9 ── goto #11
10 ─ %34 = Base.slt_int(%9, 0)::Bool
│ %35 = Base.ifelse(%34, 0, %9)::Int64
│ %36 = invoke Base.mapreduce_impl(%5::typeof(identity), %6::typeof(Base.add_sum), %4::Array{Float64,1}, 1::Int64, %35::Int64, 1024::Int64)::Float64
└─── goto #11
11 ┄ %38 = φ (#2 => 0.0, #4 => %16, #9 => %24, #10 => %36)::Float64
└─── goto #12
12 ─ goto #13
13 ─ goto #14
14 ─ goto #15
15 ─ goto #16
16 ─ goto #17
17 ─ goto #18
18 ─ return %38
) => Float64
julia> @code_warntype foo2(Int)
WARNING: I am lying to you.
Variables
#self#::Core.Compiler.Const(foo2, false)
t::Core.Compiler.Const(Int64, false)
x::Array{Int64,1}
Body::Float64
1 ─ (x = Main.ones(t, 10))
│ %2 = Main.map(Main.sin, x)::Array{Float64,1}
│ %3 = Main.sum(%2)::Float64
└── return %3 |
@code_typed/@code_warntype/etc is showing inaccurate specialization@code_typed, @code_warntype, etc. are showing inaccurate specialization
@code_typed, @code_warntype, etc. are showing inaccurate specialization
Member
|
I'd love to see this. I don't think we need to make it an option, but let's also make the warning a little less passive-aggressive. :) |
Member
Author
|
This is just a note to myself: This pull request only deals with positional arguments. We will need to also find a way to deal with inaccurate specialization on keyword arguments. |
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This is an experiment in addressing the problem described in:
@code_typedstop lying to us all? :) #32834 Can we support a way to make@code_typedstop lying to us all? :)