Does this union break strict aliasing? What about floating point registers

Question

union
{
    Uint32 Integer;
    Float32 Real;
} Field;    

I have to use that union for a little IEEE trick, does that break strict aliasing? GCC is no

Answer 1

It is UB (but doesn't require strict aliasing). Also, uniond data is always stored in memory by implementations, AFAIK, else would require knowing which register the source data came from, which means knowing the source type.