Stream: git-cranelift

Topic: cranelift / Issue #762 Some RISC legalization questions?

GitHub (Feb 28 2020 at 23:25):

alexcrichton transferred Issue #762:

Hi,

In doing my MIPS64 port I found a couple of blockers that impede support for other RISC architectures as well.

• iconst can't load immediates larger than the instruction's slot; and
• brz brnz and possibly other instructions can only operate on native-sized operands.

How do we best implement constant materialization for RISC architectures, an arch-specific approach or a generic one with knowledge of things like li/lui/shl/or?

As for the latter, I tried widen but it didn't work. I think that's because brz and similar instructions is not "polymorphic" like with those named foo.iB. How do I specify the correct widening behavior in this case?

Last updated: Dec 23 2024 at 14:03 UTC