From 9125a9cfae02758053b0f1056a93594c33bd4dcf Mon Sep 17 00:00:00 2001
From: Tim Holy <tim.holy@gmail.com>
Date: Sun, 10 Jul 2016 19:13:07 -0500
Subject: [PATCH] Faster and simpler indices for SubArray

---
 base/abstractarray.jl |  4 ++++
 base/subarray.jl      | 16 +++++-----------
 2 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/base/abstractarray.jl b/base/abstractarray.jl
index a65254b46fbe1b..554099a8218bba 100644
--- a/base/abstractarray.jl
+++ b/base/abstractarray.jl
@@ -51,6 +51,9 @@ end
 indices1{T}(A::AbstractArray{T,0}) = OneTo(1)
 indices1{T}(A::AbstractArray{T})   = (@_inline_meta; indices(A)[1])
 
+unsafe_indices(A) = indices(A)
+unsafe_indices(r::Range) = (OneTo(unsafe_length(r)),) # Ranges use checked_sub for size
+
 """
     linearindices(A)
 
@@ -252,6 +255,7 @@ Throw an error if the specified `indexes` are not in bounds for the given `array
 function checkbounds(A::AbstractArray, I...)
     @_inline_meta
     checkbounds(Bool, A, I...) || throw_boundserror(A, I)
+    nothing
 end
 function checkbounds(A::AbstractArray, i)
     @_inline_meta
diff --git a/base/subarray.jl b/base/subarray.jl
index e9a4cf1c57765a..48446fcc60cb4a 100644
--- a/base/subarray.jl
+++ b/base/subarray.jl
@@ -278,17 +278,11 @@ end
 # they are taken from the range/vector
 # Since bounds-checking is performance-critical and uses
 # indices, it's worth optimizing these implementations thoroughly
-indices(S::SubArray) = (@_inline_meta; _indices_sub(S, 1, S.indexes...))
-_indices_sub(S::SubArray, dim::Int) = ()
-_indices_sub(S::SubArray, dim::Int, ::Real, I...) = (@_inline_meta; _indices_sub(S, dim+1, I...))
-_indices_sub(S::SubArray, dim::Int, ::Colon, I...) = (@_inline_meta; (indices(parent(S), dim), _indices_sub(S, dim+1, I...)...))
-_indices_sub(S::SubArray, dim::Int, i1::AbstractArray, I...) = (@_inline_meta; (indices(i1)..., _indices_sub(S, dim+1, I...)...))
-indices1(S::SubArray) = (@_inline_meta; _indices1(S, 1, S.indexes...))
-_indices1(S::SubArray, dim) = OneTo(1)
-_indices1(S::SubArray, dim, i1::Real, I...) = (@_inline_meta; _indices1(S, dim+1, I...))
-_indices1(S::SubArray, dim, i1::Colon, I...) = (@_inline_meta; indices(parent(S), dim))
-_indices1(S::SubArray, dim, i1::AbstractArray, I...) = (@_inline_meta; indices1(i1))
-_indices1{T}(S::SubArray, dim, i1::AbstractArray{T,0}, I...) = (@_inline_meta; _indices1(S, dim+1, I...))
+indices(S::SubArray) = (@_inline_pure_meta; _indices_sub(S, indices(S.parent), S.indexes...))
+_indices_sub(S::SubArray, pinds) = ()
+_indices_sub(S::SubArray, pinds, ::Real, I...) = _indices_sub(S, tail(pinds), I...)
+_indices_sub(S::SubArray, pinds, ::Colon, I...) = (pinds[1], _indices_sub(S, tail(pinds), I...)...)
+_indices_sub(S::SubArray, pinds, i1::AbstractArray, I...) = (unsafe_indices(i1)..., _indices_sub(S, tail(pinds), I...)...)
 
 ## Compatability
 # deprecate?