> We have seen this type of stuff on Android with Dalvik (where Qualcomm has a special library / modified version of the VM). Which they achieved at the cost o

> We have seen this type of stuff on Android with Dalvik (where Qualcomm has a special library / modified version of the VM). Which they achieved at the cost of correctness: https://code.google.com/p/android/issues/detail?id=58726#c10 https://code.google.com/p/android/issues/detail?id=58726#c10 And vendors do contribute performance patches back to AOSP. ARM's Linaro group has updated & NEON-enabled some libraries, Intel contributed SSE optimizations and x86 support in general, Nvidia contributed NEON optimizations, Imgtec for MIPS support, etc... There's a cost to maintaining a downstream fork, and a slight competitive edge tends to not actually be significant enough to justify the engineering cost.