https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83487
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> --- It's this change: @@ -5660,10 +5668,12 @@ store_one_arg (struct arg_data *arg, rtx argblock, int flags, } } - emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), size_rtx, - parm_align, partial, reg, excess, argblock, - ARGS_SIZE_RTX (arg->locate.offset), reg_parm_stack_space, - ARGS_SIZE_RTX (arg->locate.alignment_pad), false); + if (!CONST_INT_P (size_rtx) || INTVAL (size_rtx) != 0) + emit_push_insn (arg->value, arg->mode, TREE_TYPE (pval), size_rtx, + parm_align, partial, reg, excess, argblock, + ARGS_SIZE_RTX (arg->locate.offset), + reg_parm_stack_space, + ARGS_SIZE_RTX (arg->locate.alignment_pad), false); /* Unless this is a partially-in-register argument, the argument is now in the stack.