Isolate string interpolation in error paths for sparse matrix constru…

…ctors (JuliaLang#38446)

This provides a better-than-3x speed improvement for `spzeros(5, 5)`:

julia> @Btime spzeros(5, 5);
  341.371 ns (3 allocations: 288 bytes)

julia> Revise.track(SparseArrays)

julia> @Btime spzeros(5, 5);
  103.633 ns (3 allocations: 288 bytes)

stdlib/SparseArrays/src/sparsematrix.jl

@@ -53,22 +53,29 @@ function sparse_check_Ti(m::Integer, n::Integer, Ti::Type)
 end
 
 function sparse_check(n::Integer, colptr::Vector{Ti}, rowval, nzval) where Ti
+ # String interpolation is a performance bottleneck when it's part of the same function,
+ # ensure we only do it once committed to the error.
+ throwstart(ckp) = throw(ArgumentError("$ckp == colptr[1] != 1"))
+ throwmonotonic(ckp, ck, k) = throw(ArgumentError("$ckp == colptr[$(k-1)] > colptr[$k] == $ck"))
+
  sparse_check_length("colptr", colptr, n+1, String) # don't check upper bound
  ckp = Ti(1)
- ckp == colptr[1] || throw(ArgumentError("$ckp == colptr[1] != 1"))
+ ckp == colptr[1] || throwstart(ckp)
  @inbounds for k = 2:n+1
  ck = colptr[k]
- ckp <= ck || throw(ArgumentError("$ckp == colptr[$(k-1)] > colptr[$k] == $ck"))
+ ckp <= ck || throwmonotonic(ckp, ck, k)
  ckp = ck
  end
  sparse_check_length("rowval", rowval, ckp-1, Ti)
  sparse_check_length("nzval", nzval, 0, Ti) # we allow empty nzval !!!
 end
 function sparse_check_length(rowstr, rowval, minlen, Ti)
+ throwmin(len, minlen, rowstr) = throw(ArgumentError("$len == length($rowstr) < $minlen"))
+ throwmax(len, max, rowstr) = throw(ArgumentError("$len == length($rowstr) >= $max"))
+
  len = length(rowval)
- len >= minlen || throw(ArgumentError("$len == length($rowstr) < $minlen"))
- !isbitstype(Ti) || len < typemax(Ti) ||
- throw(ArgumentError("$len == length($rowstr) >= $(typemax(Ti))"))
+ len >= minlen || throwmin(len, minlen, rowstr)
+ !isbitstype(Ti) || len < typemax(Ti) || throwmax(len, typemax(Ti), rowstr)
 end
 
 size(S::SparseMatrixCSC) = (getfield(S, :m), getfield(S, :n))