[stdlib] Add __rfloordiv__ to SIMD

The __rfloordiv__() method is already supported by Int and Object.
The built-in SIMD includes support for reverse division operators,
specifically __rtruediv__() and __rmod__(). Furthermore, the SIMD
library has been extended to also support __rfloordiv__().

Fixes: #2415

Signed-off-by: Peyman Barazandeh <peymanb@gmail.com>

stdlib/src/builtin/simd.mojo

@@ -1232,6 +1232,22 @@ struct SIMD[type: DType, size: Int = simdwidthof[type]()](
         constrained[type.is_numeric(), "the SIMD type must be numeric"]()
         return value / self
 
+    @always_inline("nodebug")
+    fn __rfloordiv__(self, value: Self) -> Self:
+        """Returns value / self rounded down to the nearest integer.
+
+        # Constraints:
+            The element type of the SIMD vector must be numeric.
+
+        Args:
+            value: The value that is diveded to self.
+
+        Returns:
+            `floor(value // self)`.
+        """
+        constrained[type.is_numeric(), "the type must be numeric"]()
+        return value // self
+
     # TODO: Move to global function.
     @always_inline("nodebug")
     fn fma(self, multiplier: Self, accumulator: Self) -> Self:

stdlib/test/builtin/test_simd.mojo

@@ -222,6 +222,24 @@ def test_floordiv():
     assert_equal(Float32(2) // Float32(-2), -1)
     assert_equal(Float32(99) // Float32(-2), -50)
 
+    assert_equal(
+        Int32(2) // SIMD[DType.int32, 4](2, 4, -2, -4),
+        SIMD[DType.int32, 4](1, 0, -1, -1),
+    )
+    assert_equal(
+        2 // SIMD[DType.int32, 4](2, 4, -2, -4),
+        SIMD[DType.int32, 4](1, 0, -1, -1),
+    )
+
+    assert_equal(
+        Float32(3) // SIMD[DType.float32, 4](3, -4, 1, 5),
+        SIMD[DType.float32, 4](1, -1, 3, 0),
+    )
+    assert_equal(
+        3 // SIMD[DType.float32, 4](3, -4, 1, 5),
+        SIMD[DType.float32, 4](1, -1, 3, 0),
+    )
+
 
 def test_mod():
     assert_equal(Int32(99) % Int32(1), 0)