The term used most often for this is "spilling". I figured this is what you meant by "deregistering" but I wasn't sure, so I didn't want to assume.
Registers are faster than memory. EH unwinders restore the stack before jumping to the catch block, but not the register contents.
I get that, which is why Java JITs don't use callee-saved registers. I mean, they use all the physical registers, of course, but their calling convention does not have callee-saved registers.
But what's a variable, really? After SSA renaming, optimization, SSA deconstruction, then liveness analysis, coalescing, and finally live-range splitting, variables are history and the register allocator is only dealing with live ranges, typically.
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The term used most often for this is "spilling". I figured this is what you meant by "deregistering" but I wasn't sure, so I didn't want to assume.
I get that, which is why Java JITs don't use callee-saved registers. I mean, they use all the physical registers, of course, but their calling convention does not have callee-saved registers.
"spilling" usually means a variable is sometimes in a register, sometimes on the stack. "Enregistering" means it is full time in a register.
But what's a variable, really? After SSA renaming, optimization, SSA deconstruction, then liveness analysis, coalescing, and finally live-range splitting, variables are history and the register allocator is only dealing with live ranges, typically.