I wouldn't call Xeon Phi x86: - It doesn't support CMOV, MMX, SSE, AVX, and all other ISA extensions the popped up after the original Pentium. - It does not u

I wouldn't call Xeon Phi x86: - It doesn't support CMOV, MMX, SSE, AVX, and all other ISA extensions the popped up after the original Pentium. - It does not use standard System V x86-64 ABI. - Most of its compute power is due to special vector instruction set, that is not compatible with any previous or future x86 ISA (including AVX-512). - The only fully supported compiler is Intel Compiler (icc). And in my opinion, its code-generation quality for Xeon Phi is far worse than for other Intel architectures. - The only supported assembler is GAS. No NASM, no YASM. - Most debugging and profiling utilities (that run fine on normal x86 cores) are not supported on Xeon Phi. This includes valgrind, Address Sanitizer, Thread Sanitizer, and even memory profiling options in Intel compiler. Given these limitations, how does it help that Xeon Phi is x86-based?