RISC-V Conditional Moves
4 days ago
- #Conditional Moves
- #Branch Fusion
- #RISC-V
- RISC-V lacks a direct equivalent to aarch64's csel family of instructions, which can evaluate conditional moves.
- Special cases of conditional operations in RISC-V are handled by extensions like Zbb (min/max) and Zicond (czero.eqz/nez).
- RISC-V design principles make it unlikely to introduce direct equivalents of conditional operations found in other ISAs.
- Branch fusion in RISC-V aims to convert short forward branches into conditional moves, but this can violate the memory model.
- Control dependencies in RISC-V are stronger than in some other contexts, affecting how branches and conditional moves interact with memory operations.
- Fusing branches into conditional moves must retain branch-like properties to comply with RISC-V's memory consistency model.