It seems sb is trying to create an operation that tries to use two distinct relative indices within the same instruction, this is forbidden and the scheduler gets stuck. from the post scheduler dump: # 0.y => t175||FP@R0.y # 0.z => t194||FP@R0.z new current_AR assigned: R13.x.235@R0.w current_AR is R13.x.235@R0.w trying to use R15.x.126@R1.x current_AR is R13.x.235@R0.w trying to use R15.x.126@R1.x !!!!!! interf slot: 0 : ADD t80@R1.x, A26.y[R13.x.235@R0.w]_608F@R5.y, \ A26.y[R15.x.126@R1.x]_609F@R5.y