while loops

compiler/hir/hir.odin

@@ -141,6 +141,7 @@ Stmt_Kind :: enum u8 {
 	Sink,
 	Trap,
 	If,
+	While,
 }
 
 Stmt :: struct {
@@ -151,8 +152,11 @@ Stmt :: struct {
 	expr:       Expr_Id,
 	// `If` statements use `expr` as the condition and `then_body`/`else_body` as
 	// the branch statement lists.
+	// `While` statements use `expr` as the condition, `then_body` as the loop
+	// body, and `update` as the optional post-iteration statement.
 	then_body:  []Stmt_Id,
 	else_body:  []Stmt_Id,
+	update:     Stmt_Id,
 	diagnostic: source.Diagnostic_Id,
 }