Feature: Update Backend Options from Target

[Philipp van Kempen]

Some backends allow target specific optimizations. Especially TVM support the following target specific flags to enable specific schedules or features:

• device (i.e. arm_cpu, cuda,...)
• mcpu
• model
• mattr (i.e. +neon)
• keys

We should find a way to update these automatically given the used target. (i.e. to enable usage of SIMD intrisincs which are only available on a given set of devices). However this transformation should be optional and thus should be enabled explicitly. By default, generic (portable) implementations should be used by the backend.

Open questions:

• How would we name such feature (i.e. overwriteopts)? Or should it just be a per-target config option (i.e. spike.overwrite_backend_options=1)?