Add/unify broadcast in mul! with Diagonal (#574)

Author: tam724

src/host/linalg.jl

@@ -283,7 +283,8 @@ function LinearAlgebra.mul!(B::AbstractGPUVecOrMat,
     m′, n′ = size(B, 1), size(B, 2)
     n == d || throw(DimensionMismatch("left hand side has $n columns but D is $d by $d"))
     (m, n) == (m′, n′) || throw(DimensionMismatch("expect output to be $m by $n, but got $m′ by $n′"))
-    B .= A .* transpose(dd)
+    ddT = transpose(dd)
+    @. B = A * ddT
 
     B
 end
@@ -299,7 +300,8 @@ function LinearAlgebra.mul!(B::AbstractGPUVecOrMat,
     m′, n′ = size(B, 1), size(B, 2)
     n == d || throw(DimensionMismatch("left hand side has $n columns but D is $d by $d"))
     (m, n) == (m′, n′) || throw(DimensionMismatch("expect output to be $m by $n, but got $m′ by $n′"))
-    B .= α * A .* transpose(dd) + β * B
+    ddT = transpose(dd)
+    @. B = α * A * ddT + β * B
 
     B
 end