Constructor of `fp_t` is not honoured

[zhuanhao-wu]

Here, we are constructing an FP, which is fp_t from rn:

// Constructor used
	fp_t(ui_t ui)
	{
		(sign,expo,frac) = ui;
	}

// usage
fp = FP(rn);

But we are only generating a node without further information.

hBinop = [
  hVarref fp_mc_proc_local_2 NOLIST
  hVarref rn_mc_proc_local_9 NOLIST
]

However, we can circumvent this issue by manually inlining the constructor.

#329