use firstindex in CartesianIndices's simd_index

`first(Base.axes1())` works well, but `length(::StepRange)` won't be omitted by LLVM if `step` is unknown at compile time.
JuliaLang · Dec 23, 2021 · 86d4375 · 86d4375
1 parent f9d771e
commit 86d4375
Showing 1 changed file with 2 additions and 3 deletions.
diff --git a/base/multidimensional.jl b/base/multidimensional.jl
@@ -483,9 +483,8 @@ module IteratorsMD
     simd_inner_length(iter::CartesianIndices, I::CartesianIndex) = Base.length(iter.indices[1])
 
     simd_index(iter::CartesianIndices{0}, ::CartesianIndex, I1::Int) = first(iter)
-    @propagate_inbounds function simd_index(iter::CartesianIndices, Ilast::CartesianIndex, I1::Int)
-        CartesianIndex(getindex(iter.indices[1], I1+first(Base.axes1(iter.indices[1]))), Ilast.I...)
-    end
+    @propagate_inbounds simd_index(iter::CartesianIndices, Ilast::CartesianIndex, I1::Int) =
+        CartesianIndex(iter.indices[1][I1+firstindex(iter.indices[1])], Ilast)
 
     # Split out the first N elements of a tuple
     @inline function split(t, V::Val)