HPC ASIC requires -mstrict-align

[hegza]

As per topic. I made #94 to try and address this but I couldn't quickly think of a way to prove or disprove if that actually works.

[hegza]

A surefire way to fix this would be to force a rebuild of the standard library (might require nightly) and define our own "target.json". We should do the latter anyway:

rustc +nightly -Z unstable-options --target=riscv64imac-unknown-none-elf --print target-spec-json > hpc.json

then edit this file to have +mstrict-align where appropriate.

Finally, we should make sure our compiler is building against this target specification instead of the built-in one.

[hegza]

Apparently the RISC-V compilers don't support the codegen option for -mstrict-align. Instead there are options such as:

unaligned-scalar-mem - Has reasonably performant unaligned scalar loads and stores. (supported by rustc)
zicclsm - 'Zicclsm' (Main Memory Supports Misaligned Loads/Stores). (supported by LLVM but not rustc)

This leads me to believe that perhaps strict alignment is the RISC-V default. I guess @andstepan was right 😃