Re:A new register allocator for ZJIT
by djwatson24 on Saturday May 30, 2026 @04:25AM
(#48333974)
I’ve always wondered about linear scan vs SSA based spilling & regalloc, like libfirm & qbe use:
‘Register spilling and live-range splitting for SSA-form programs’ and ‘Preference-Guided Register Assignment’
It’s much cleaner to code, since you don’t need to generate live ranges explicitly, and can break it up in two passes. Linear scan creates new inactive /active intervals, while the ssa form allocators just reuse the ssa graph. I’ve never benchmarked them back to back though.
‘Register spilling and live-range splitting for SSA-form programs’ and ‘Preference-Guided Register Assignment’
It’s much cleaner to code, since you don’t need to generate live ranges explicitly, and can break it up in two passes. Linear scan creates new inactive /active intervals, while the ssa form allocators just reuse the ssa graph. I’ve never benchmarked them back to back though.