add neg-stride support to spr!

test added

Author: N5N3

stdlib/LinearAlgebra/src/blas.jl

@@ -1167,16 +1167,16 @@ for (fname, elty) in ((:dspr_, :Float64),
 end
 
 function spr!(uplo::AbstractChar,
-              α::Real, x::Union{DenseArray{T}, AbstractVector{T}},
-              AP::Union{DenseArray{T}, AbstractVector{T}}) where {T <: BlasReal}
+              α::Real, x::AbstractArray{T},
+              AP::AbstractArray{T}) where {T <: BlasReal}
     chkuplo(uplo)
     require_one_based_indexing(AP, x)
     N = length(x)
     if 2*length(AP) < N*(N + 1)
         throw(DimensionMismatch("Packed symmetric matrix A has size smaller than length(x) = $(N)."))
     end
     chkstride1(AP)
-    return spr!(uplo, N, convert(T, α), x, stride(x, 1), AP)
+    return GC.@preserve x spr!(uplo, N, T(α), vec_pointer_stride(x)..., AP)
 end
 
 """

stdlib/LinearAlgebra/test/blas.jl

@@ -291,8 +291,6 @@ end
                 M = rand(elty, n, n)
                 AL = Symmetric(M, :L)
                 AU = Symmetric(M, :U)
-                x = rand(elty, n)
-
                 function pack(A, uplo)
                     AP = elty[]
                     for j in 1:n
@@ -302,28 +300,29 @@ end
                     end
                     return AP
                 end
-
-                ALP_result_julia_lower = pack(α*x*x' + AL, :L)
-                ALP_result_blas_lower = pack(AL, :L)
-                BLAS.spr!('L', α, x, ALP_result_blas_lower)
-                @test ALP_result_julia_lower ≈ ALP_result_blas_lower
-                ALP_result_blas_lower = append!(pack(AL, :L), ones(elty, 10))
-                BLAS.spr!('L', α, x, ALP_result_blas_lower)
-                @test ALP_result_julia_lower ≈ ALP_result_blas_lower[1:end-10]
-                ALP_result_blas_lower = reshape(pack(AL, :L), 1, length(ALP_result_julia_lower), 1)
-                BLAS.spr!('L', α, x, ALP_result_blas_lower)
-                @test ALP_result_julia_lower ≈ vec(ALP_result_blas_lower)
-
-                AUP_result_julia_upper = pack(α*x*x' + AU, :U)
-                AUP_result_blas_upper = pack(AU, :U)
-                BLAS.spr!('U', α, x, AUP_result_blas_upper)
-                @test AUP_result_julia_upper ≈ AUP_result_blas_upper
-                AUP_result_blas_upper = append!(pack(AU, :U), ones(elty, 10))
-                BLAS.spr!('U', α, x, AUP_result_blas_upper)
-                @test AUP_result_julia_upper ≈ AUP_result_blas_upper[1:end-10]
-                AUP_result_blas_upper = reshape(pack(AU, :U), 1, length(AUP_result_julia_upper), 1)
-                BLAS.spr!('U', α, x, AUP_result_blas_upper)
-                @test AUP_result_julia_upper ≈ vec(AUP_result_blas_upper)
+                for x in (rand(elty, n), view(rand(elty, n), n:-1:1))
+                    ALP_result_julia_lower = pack(α*x*x' + AL, :L)
+                    ALP_result_blas_lower = pack(AL, :L)
+                    BLAS.spr!('L', α, x, ALP_result_blas_lower)
+                    @test ALP_result_julia_lower ≈ ALP_result_blas_lower
+                    ALP_result_blas_lower = append!(pack(AL, :L), ones(elty, 10))
+                    BLAS.spr!('L', α, x, ALP_result_blas_lower)
+                    @test ALP_result_julia_lower ≈ ALP_result_blas_lower[1:end-10]
+                    ALP_result_blas_lower = reshape(pack(AL, :L), 1, length(ALP_result_julia_lower), 1)
+                    BLAS.spr!('L', α, x, ALP_result_blas_lower)
+                    @test ALP_result_julia_lower ≈ vec(ALP_result_blas_lower)
+
+                    AUP_result_julia_upper = pack(α*x*x' + AU, :U)
+                    AUP_result_blas_upper = pack(AU, :U)
+                    BLAS.spr!('U', α, x, AUP_result_blas_upper)
+                    @test AUP_result_julia_upper ≈ AUP_result_blas_upper
+                    AUP_result_blas_upper = append!(pack(AU, :U), ones(elty, 10))
+                    BLAS.spr!('U', α, x, AUP_result_blas_upper)
+                    @test AUP_result_julia_upper ≈ AUP_result_blas_upper[1:end-10]
+                    AUP_result_blas_upper = reshape(pack(AU, :U), 1, length(AUP_result_julia_upper), 1)
+                    BLAS.spr!('U', α, x, AUP_result_blas_upper)
+                    @test AUP_result_julia_upper ≈ vec(AUP_result_blas_upper)
+                end
             end
         end