selfhost: fix 4B array load/store width + 8B uninit zero-init

test/wcc/990_selfhost.c

@@ -345,6 +345,24 @@ probe_ww_compile(const char *bin)
 		  "  dec(&c); dec(&c); dec(&c);\n"
 		  "  return c.x;\n"
 		  "};", 2 },
+		/* Uninit `[8]u8` local — raw size 8B, C cgen zero-inits via
+		 * `MOVQ $0, off(BP)`. Pre-fix the wwstage left the slot
+		 * holding stack junk and `buf[0]` returned non-zero. */
+		{ "fn main() i32 = {\n"
+		  "  let buf: [8]u8;\n"
+		  "  return buf[0]: i32;\n"
+		  "};", 0 },
+		/* [N]i32 indexed write + read: MOVL store, MOVSXD load.
+		 * Pre-fix the wwstage emitted MOVQ in both directions —
+		 * overwrites adjacent slots and loads the wrong width.
+		 * arr[0..3] = -7, 3, 11, sum = 7. */
+		{ "fn main() i32 = {\n"
+		  "  let arr: [3]i32;\n"
+		  "  arr[0] = 0 - 7;\n"
+		  "  arr[1] = 3;\n"
+		  "  arr[2] = 11;\n"
+		  "  return arr[0] + arr[1] + arr[2];\n"
+		  "};", 7 },
 		/* Hare-style for-range over a slice: `for (let b .. s)`.
 		 * Allocates `.rgi`/`.rgl` scratch slots, walks i=0..s.len
 		 * loading s.ptr[i] into the binding. esz=1 here so the