Sam Westrick @shwestrick.bsky.social · 24/07/2025oof, yep, looks like the (seemingly unrelated) compiler optimization somehow caused a temporary to be reassigned from register to stack, with ~20% additional spilling cost 1110
Sam Westrick @shwestrick.bsky.social · 24/07/2025the loop requires a signal handling poll on each go-around (the yellow part at the bottom) dropping off the bottom of the loop enters the signal handling code entry into a signal handler is a safe-point, and all live vars (including k and x) need to be on the stack 110
Sam Westrick @shwestrick.bsky.social · 24/07/2025the signal handling code isn't shown, but basically, in the first version, the first thing that happens off the bottom of the loop is saving k and x to the stack. This is good for performance, because signal handling is a rare operation, avoiding the spilling cost within the loop 110
