Branch on Bool alpha in scaling mul!

Author: jishnub

src/generic.jl

@@ -202,24 +202,37 @@ _lscale_add!(C::StridedArray, s::Number, X::StridedArray, alpha::Number, beta::N
     generic_mul!(C, s, X, alpha, beta)
 @inline function _lscale_add!(C::AbstractArray, s::Number, X::AbstractArray, alpha::Number, beta::Number)
     if axes(C) == axes(X)
-        if isone(alpha)
-            if iszero(beta)
-                @. C = s * X
-            else
-                @. C = s * X + C * beta
-            end
-        else
-            if iszero(beta)
-                @. C = s * X * alpha
-            else
-                @. C = s * X * alpha + C * beta
-            end
-        end
+        iszero(alpha) && return _rmul_or_fill!(C, beta)
+        _lscale_add_nonzeroalpha!(C, s, X, alpha, beta)
     else
         generic_mul!(C, s, X, alpha, beta)
     end
     return C
 end
+function _lscale_add_nonzeroalpha!(C::AbstractArray, s::Number, X::AbstractArray, alpha::Number, beta::Number)
+    if isone(alpha)
+        if iszero(beta)
+            @. C = s * X
+        else
+            @. C = s * X + C * beta
+        end
+    else
+        if iszero(beta)
+            @. C = s * X * alpha
+        else
+            @. C = s * X * alpha + C * beta
+        end
+    end
+    C
+end
+function _lscale_add_nonzeroalpha!(C::AbstractArray, s::Number, X::AbstractArray, alpha::Bool, beta::Number)
+    if iszero(beta)
+        @. C = s * X
+    else
+        @. C = s * X + C * beta
+    end
+    C
+end
 @inline mul!(C::AbstractArray, X::AbstractArray, s::Number, alpha::Number, beta::Number) =
     _rscale_add!(C, X, s, alpha, beta)