From db570dfb8d7607d98e71d092a2933a44bf4e3f55 Mon Sep 17 00:00:00 2001
From: Lilith Orion Hafner <lilithhafner@gmail.com>
Date: Tue, 19 Jul 2022 11:05:30 -0400
Subject: [PATCH] Stop using view in adaptive sort (#45699)

---
 base/sort.jl | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/base/sort.jl b/base/sort.jl
index 0eb2ae8a5b4be..35d7d7344d59d 100644
--- a/base/sort.jl
+++ b/base/sort.jl
@@ -12,7 +12,7 @@ using .Base: copymutable, LinearIndices, length, (:), iterate, OneTo,
     extrema, sub_with_overflow, add_with_overflow, oneunit, div, getindex, setindex!,
     length, resize!, fill, Missing, require_one_based_indexing, keytype, UnitRange,
     min, max, reinterpret, signed, unsigned, Signed, Unsigned, typemin, xor, Type, BitSigned, Val,
-    midpoint
+    midpoint, @boundscheck, checkbounds
 
 using .Base: >>>, !==
 
@@ -761,6 +761,13 @@ function _extrema(v::AbstractVector, lo::Integer, hi::Integer, o::Ordering)
     end
     mn, mx
 end
+function _issorted(v::AbstractVector, lo::Integer, hi::Integer, o::Ordering)
+    @boundscheck checkbounds(v, lo:hi)
+    @inbounds for i in (lo+1):hi
+        lt(o, v[i], v[i-1]) && return false
+    end
+    true
+end
 function sort!(v::AbstractVector{T}, lo::Integer, hi::Integer, a::AdaptiveSort, o::Ordering,
             t::Union{AbstractVector{T}, Nothing}=nothing) where T
     # if the sorting task is not UIntMappable, then we can't radix sort or sort_int_range!
@@ -779,11 +786,11 @@ function sort!(v::AbstractVector{T}, lo::Integer, hi::Integer, a::AdaptiveSort,
     # For most arrays, a presorted check is cheap (overhead < 5%) and for most large
     # arrays it is essentially free (<1%). Insertion sort runs in a fast O(n) on presorted
     # input and this guarantees presorted input will always be efficiently handled
-    issorted(view(v, lo:hi), o) && return v
+    _issorted(v, lo, hi, o) && return v
 
     # For large arrays, a reverse-sorted check is essentially free (overhead < 1%)
-    if lenm1 >= 500 && issorted(view(v, lo:hi), ReverseOrdering(o))
-        reverse!(view(v, lo:hi))
+    if lenm1 >= 500 && _issorted(v, lo, hi, ReverseOrdering(o))
+        reverse!(v, lo, hi)
         return v
     end