[wip] make backend aware of operand length

7 jobs from master in 19 minutes and 19 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #230
test:cargo:api

02:36

failed #232
test:cargo:compiler

02:56

passed #231
test:cargo:ir

02:53

passed #233
test:cargo:runtime

03:36

failed #235
testjit:binops

02:01

failed #236
testjit:cmpops

02:24

failed #234
testjit:milestones

02:50