[jcranmer]

Sorry, no. IEEE 754 is correctly implemented in pretty much all modern hardware [1], save for the fact that optional operations (e.g., the suggested transcendental operations) are not implemented.

The problem you run into is that the compiler generally does not implement the IEEE 754 model fully strictly, especially under default flags--you have to opt into strict IEEE 754 conformance, and even there, I'd be wary of the potential for bugs. (Hence one of the things I'm working on, quite slowly, is a special custom compiler that is designed to have 100% predictable assembly output for floating-point operations so that I can test some floating-point implementation things without having to worry about pesky optimizations interfering with me).

[1] The biggest stumbling block is denormal support: a lot of processors opted to support denormals only by trapping on it and having an OS-level routine to fix up the output. That said, both AMD and Apple have figured out how to support denormals in hardware with no performance penalty (Intel has some way to go), and from what I can tell, even most GPUs have given up and added full denormal support as well.