func (f *File) endsBasicSourceBlock(s ast.Stmt) bool {
	switch s := s.(type) {
	case *ast.BlockStmt:
		// Treat blocks like basic blocks to avoid overlapping counters.
		return true
	case *ast.BranchStmt:
		return true
	case *ast.ForStmt:
		return true
	case *ast.IfStmt:
		return true
	case *ast.LabeledStmt:
		return true // A goto may branch here, starting a new basic block.
	case *ast.RangeStmt:

	if len(list) == 3 && list[0].Op() == ir.ODCL {
		dcl = list[0].(*ir.Decl)
		list = list[1:]
	}
	if len(list) != 2 ||
		list[0].Op() != ir.OAS2 ||
		list[1].Op() != ir.OGOTO ||
		list[1].(*ir.BranchStmt).Label != label {
		return false
	}
	as2body := list[0].(*ir.AssignListStmt)
	if dcl == nil {
		ainit := as2body.Init()
		if len(ainit) != 1 || ainit[0].Op() != ir.ODCL {
			return false
		}

			u.node(node.Tag)
		}
		u.node(node.Body)
	case *ast.CaseClause:
		u.exprs(node.List)
		defer u.scoped()()
		for _, stmt := range node.Body {
			u.node(stmt)
		}
	case *ast.BranchStmt:
	case *ast.ExprStmt:
		u.node(node.X)
	case *ast.AssignStmt:
		if node.Tok != token.DEFINE {
			u.exprs(node.Rhs)
			u.exprs(node.Lhs)
			break
		}
		lhs := node.Lhs

				p.exprList(token.NoPos, s.Results, 1, noIndent, token.NoPos, false)
				p.print(unindent)
			} else {
				p.exprList(token.NoPos, s.Results, 1, 0, token.NoPos, false)
			}
		}

	case *ast.BranchStmt:
		p.print(s.Tok)
		if s.Label != nil {
			p.print(blank)
			p.expr(s.Label)
		}

	case *ast.BlockStmt:
		p.block(s, 1)

	case *ast.IfStmt:
		p.print(token.IF)

		{"BlockStmt", Type, 0},
		{"BlockStmt.Lbrace", Field, 0},
		{"BlockStmt.List", Field, 0},
		{"BlockStmt.Rbrace", Field, 0},
		{"BranchStmt", Type, 0},
		{"BranchStmt.Label", Field, 0},
		{"BranchStmt.Tok", Field, 0},
		{"BranchStmt.TokPos", Field, 0},
		{"CallExpr", Type, 0},
		{"CallExpr.Args", Field, 0},
		{"CallExpr.Ellipsis", Field, 0},
		{"CallExpr.Fun", Field, 0},

		if s.curBlock != nil {
			b := s.endBlock()
			b.AddEdgeTo(lab.target)
		}
		s.startBlock(lab.target)

	case ir.OGOTO:
		n := n.(*ir.BranchStmt)
		sym := n.Label

		lab := s.label(sym)
		if lab.target == nil {
			lab.target = s.f.NewBlock(ssa.BlockPlain)
		}

		b := s.endBlock()

pkg go/ast, type BlockStmt struct, List []Stmt
pkg go/ast, type BlockStmt struct, Rbrace token.Pos
pkg go/ast, type BranchStmt struct
pkg go/ast, type BranchStmt struct, Label *Ident
pkg go/ast, type BranchStmt struct, Tok token.Token
pkg go/ast, type BranchStmt struct, TokPos token.Pos
pkg go/ast, type CallExpr struct
pkg go/ast, type CallExpr struct, Args []Expr