Specialize tuple setindex to avoid ntuple-related performance regress…

…ion. (#46050) (cherry picked from commit d7c56ba)
JuliaLang · Jul 20, 2022 · 1549064 · 1549064
1 parent bfc7e3e
commit 1549064
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Showing 2 changed files with 5 additions and 2 deletions.
diff --git a/base/tuple.jl b/base/tuple.jl
@@ -55,9 +55,9 @@ function setindex(x::Tuple, v, i::Integer)
     _setindex(v, i, x...)
 end
 
-function _setindex(v, i::Integer, args...)
+function _setindex(v, i::Integer, args::Vararg{Any,N}) where {N}
     @inline
-    return ntuple(j -> ifelse(j == i, v, args[j]), length(args))
+    return ntuple(j -> ifelse(j == i, v, args[j]), Val{N}())
 end
 
 

diff --git a/test/tuple.jl b/test/tuple.jl
@@ -710,3 +710,6 @@ g42457(a, b) = Base.isequal(a, b) ? 1 : 2.0
 @test only(Base.return_types(g42457, (NTuple{3, Int}, Tuple))) === Union{Float64, Int}
 @test only(Base.return_types(g42457, (NTuple{3, Int}, NTuple))) === Union{Float64, Int}
 @test only(Base.return_types(g42457, (NTuple{3, Int}, NTuple{4}))) === Float64
+
+# issue #46049: setindex(::Tuple) regression
+@inferred Base.setindex((1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16), 42, 1)