Unification is an algorithm where eqv? is often the slow part in Gambit; I fired up schelog with the reverse benchmark and got the following. So inlining eqv? does seem to be worth something.
With r5rs semantics:
without inlining eqv?
[brad:~/Desktop/schelog] lucier% gsi -:m100000 reverse.o1 (time (do ((i 0 (+ i 1))) ((= i 100) (void)) (%which (l) (%reverse data l)))) 344 ms real time 314 ms cpu time (308 user, 6 system) no collections 47933504 bytes allocated no minor faults no major faults
with inlining eqv?:
[brad:~/Desktop/schelog] lucier% gsi -:m100000 reverse.o2 (time (do ((i 0 (+ i 1))) ((= i 100) (void)) (%which (l) (%reverse data l)))) 235 ms real time 214 ms cpu time (209 user, 5 system) no collections 47933504 bytes allocated no minor faults no major faults
With r6rs semantics:
No inlining eqv?
[brad:~/Desktop/schelog] lucier% gsi -:m100000 reverse.o4 (time (do ((i 0 (+ i 1))) ((= i 100) (void)) (%which (l) (%reverse data l)))) 365 ms real time 237 ms cpu time (228 user, 9 system) no collections 49325408 bytes allocated no minor faults no major faults
with inlining eqv?:
[brad:~/Desktop/schelog] lucier% gsi -:m100000 reverse.o3 (time (do ((i 0 (+ i 1))) ((= i 100) (void)) (%which (l) (%reverse data l)))) 155 ms real time 131 ms cpu time (124 user, 7 system) no collections 49325408 bytes allocated no minor faults no major faults
Just for info, with (standard-bindings)(block)(fixnum)(not safe) (so eqv? == eq?)
[brad:~/Desktop/schelog] lucier% gsi -:m100000 reverse.o6 (time (do ((i 0 (+ i 1))) ((= i 100) (void)) (%which (l) (%reverse data l)))) 131 ms real time 106 ms cpu time (99 user, 7 system) no collections 49325728 bytes allocated no minor faults no major faults