add branch_0
add branch_5
add branch_6
add branch_7
coalesce branch_7 and branch_5 at time 0.69324776497
coalesce branch_7 and branch_6 at time 2.21364712332
coalesce branch_0 and branch_7 at time 3.0576032306
coalesce branch_3 and branch_0 at time 9.51196193869