a warning to implement

[Gabriel Dos Reis]

Joe Buck <jbuck@synopsys.com> writes:

| Robert writes:
| > But Gaby, right now, the construct
| > 
| >  int a = a;
| > 
| > produces an undefined result, so no one can use it. It might suppress
| > warnings in one version of gcc, but then someone might submit a patch
| > that causes it to have some disastrous effect, and no one would have
| > a right to complain, since if they are using this, they are using an
| > undocumented behavior, and have no right to count on it.
| 
| One possible disasterous effect is that
| 	float a = a;
| with debugging off might generate an actual load and store, and if it
| reads stack noise that looks like a signalling NaN, boom.

It is defined to copy a signalling NaN.

-- Gaby