fix typo in Float32 random number generation (#57338)

introduced in #56144

---------

Co-authored-by: Mosè Giordano <[email protected]>

Author: KristofferC

stdlib/Random/src/XoshiroSimd.jl

@@ -46,7 +46,7 @@ simdThreshold(::Type{Bool}) = 640
     ui = (x>>>32) % UInt32
     li = x % UInt32
     u = _uint2float(ui, Float32)
-    l = _uint2float(ui, Float32)
+    l = _uint2float(li, Float32)
     (UInt64(reinterpret(UInt32, u)) << 32) | UInt64(reinterpret(UInt32, l))
 end
 @inline function _bits2float(x::UInt64, ::Type{Float16})

stdlib/Random/test/runtests.jl

@@ -1250,6 +1250,16 @@ end
     @test length(xs) == 3
 end
 
+@testset "Float32 RNG typo" begin
+    for T in (Float16, Float32, Float64)
+        # Make sure generated numbers are sufficiently diverse
+        # for both SIMD and non-SIMD RNG code paths for all types.
+        @test length(unique!(rand(T, 7))) > 3
+        @test length(unique!(rand(T, 14))) > 10
+        @test length(unique!(rand(T, 34))) > 20
+    end
+end
+
 @testset "Docstrings" begin
     @test isempty(Docs.undocumented_names(Random))
 end