[tjalfi]

AMD GPUs use a non-zero NULL pointer[0].

[0] https://reviews.llvm.org/D26196

[nsajko]

Interesting. And it isn't even always non-zero; sometimes it's 32-bit -1, sometimes it's 32-bit 0 and sometimes it's 64-bit 0:

https://llvm.org/docs/AMDGPUUsage.html#address-spaces