add parametrized vector width

Signed-off-by: martinvuyk <[email protected]>

stdlib/src/memory/span.mojo

@@ -49,6 +49,7 @@ struct _SpanSIMDIter[
     D: DType,
     span_origin: Origin[False],
     iter_origin: Origin[True],
+    width: Int,
     forward: Bool = True,
 ]:
     """SIMD Iterator for Span.
@@ -57,6 +58,7 @@ struct _SpanSIMDIter[
         D: The DType of the elements in the span.
         span_origin: The origin of the Span.
         iter_origin: The origin of the _SpanIter.
+        width: The width of the resulting vector.
         forward: The iteration direction. `False` is backwards.
 
     Notes:
@@ -79,7 +81,6 @@ struct _SpanSIMDIter[
     .
     """
 
-    alias _width = simdwidthof[D]()
     var src: Pointer[
         _SpanIter[Scalar[D], span_origin, forward=forward], iter_origin
     ]
@@ -89,35 +90,35 @@ struct _SpanSIMDIter[
         return self
 
     @always_inline
-    fn __next__(mut self) -> SIMD[D, Self._width]:
+    fn __next__(mut self) -> SIMD[D, width]:
         @parameter
         if forward:
             var i = self.src[].index
-            self.src[].index += Self._width
-            return (self.src[].src.unsafe_ptr() + i).load[width = Self._width]()
+            self.src[].index += width
+            return (self.src[].src.unsafe_ptr() + i).load[width=width]()
         else:
-            self.src[].index -= Self._width
+            self.src[].index -= width
             return (
                 (self.src[].src.unsafe_ptr() + self.src[].index)
-                .load[width = Self._width]()
+                .load[width=width]()
                 .reversed()
             )
 
     @always_inline
     fn __has_next__(self) -> Bool:
         @parameter
         if forward:
-            return (len(self.src[].src) - self.src[].index) >= Self._width
+            return (len(self.src[].src) - self.src[].index) >= width
         else:
             return self.src[].index > 0
 
     @always_inline
     fn __len__(self) -> Int:
         @parameter
         if forward:
-            return (len(self.src[].src) - self.src[].index) // Self._width
+            return (len(self.src[].src) - self.src[].index) // width
         else:
-            return self.src[].index // Self._width
+            return self.src[].index // width
 
 
 @value
@@ -154,12 +155,17 @@ struct _SpanIter[
             return Pointer.address_of(self.src[self.index])
 
     fn vectorized[
-        D: DType, O: ImmutableOrigin, //
+        D: DType, O: ImmutableOrigin, //, width: Int = simdwidthof[D]()
     ](mut self: _SpanIter[Scalar[D], O, forward=True]) -> _SpanSIMDIter[
-        D, O, __origin_of(self), forward=True
+        D, O, __origin_of(self), width, forward=True
     ]:
         """Return a vectorized Span iterator.
 
+        Parameters:
+            D: The DType of the elements in the span.
+            O: The origin of the Span.
+            width: The width of the resulting vector.
+
         Notes:
             This iterator should be used on 2 loops.
 
@@ -179,7 +185,7 @@ struct _SpanIter[
         ```
         .
         """
-        return _SpanSIMDIter[D, O, __origin_of(self), forward=True](
+        return _SpanSIMDIter[D, O, __origin_of(self), width, forward=True](
             Pointer.address_of(self)
         )