[stdlib] Fix inconsistency with UnsafePointer[SIMD[bool]]

stdlib/src/memory/unsafe_pointer.mojo

@@ -479,6 +479,23 @@ struct UnsafePointer[
             "both volatile and invariant cannot be set at the same time",
         ]()
 
+        # bool load unpacks bits differently depending on the width.
+        # This causes issues when doing stores and loads of different widths.
+        # Cast between uint8 to keep a consistent representation in memory.
+        # TODO: decide how/whether to pack SIMD[bool] bits in memory
+        @parameter
+        if type == DType.bool:
+            return (
+                self.bitcast[UInt8]()
+                .load[
+                    width=width,
+                    alignment=alignment,
+                    volatile=volatile,
+                    invariant=invariant,
+                ]()
+                .cast[type]()
+            )
+
         @parameter
         if is_nvidia_gpu() and sizeof[type]() == 1 and alignment == 1:
             # LLVM lowering to PTX incorrectly vectorizes loads for 1-byte types
@@ -785,6 +802,17 @@ struct UnsafePointer[
             alignment > 0, "alignment must be a positive integer value"
         ]()
 
+        # bool store packs bits differently depending on the width.
+        # This causes issues when doing stores and loads of different widths.
+        # Cast between uint8 to keep a consistent representation in memory.
+        # TODO: decide how/whether to pack SIMD[bool] bits in memory
+        @parameter
+        if type == DType.bool:
+            self.bitcast[UInt8]()._store[
+                alignment=alignment, volatile=volatile
+            ](val.cast[DType.uint8]())
+            return
+
         @parameter
         if volatile:
             __mlir_op.`pop.store`[

stdlib/test/memory/test_unsafepointer.mojo

@@ -316,12 +316,34 @@ def test_volatile_load_and_store_simd():
     for i in range(0, 16, 4):
         var vec = ptr.load[width=4, volatile=True](i)
         assert_equal(vec, SIMD[DType.int8, 4](i, i + 1, i + 2, i + 3))
+    ptr.free()
 
     var ptr2 = UnsafePointer[Int8].alloc(16)
     for i in range(0, 16, 4):
         ptr2.store[volatile=True](i, SIMD[DType.int8, 4](i))
     for i in range(16):
         assert_equal(ptr2[i], i // 4 * 4)
+    ptr2.free()
+
+    # test for bool store/load consistency with different widths
+    var ptr3 = UnsafePointer[Scalar[DType.bool]].alloc(4)
+    ptr3.store[volatile=True](SIMD[DType.bool, 2](True, False))
+    ptr3[2] = False
+    ptr3[3] = True
+    assert_equal(
+        ptr3.load[width=4, volatile=True](),
+        SIMD[DType.bool, 4](True, False, False, True),
+    )
+    ptr3.free()
+
+    var ptr4 = UnsafePointer[Scalar[DType.bool]].alloc(4)
+    ptr4.store[volatile=True](SIMD[DType.bool, 4](True, False, False, True))
+    assert_equal(
+        ptr3.load[width=2, volatile=True](), SIMD[DType.bool, 2](True, False)
+    )
+    assert_equal(ptr4[2], False)
+    assert_equal(ptr4[3], True)
+    ptr4.free()
 
 
 def main():