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Schedule instructions on a VLIW pipeline

AnthropicSoftware Engineer · Onsite

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This question evaluates proficiency in VLIW instruction scheduling, pipeline hazard analysis (RAW/WAR/WAW), register-pressure management, and software-pipelining for loop kernels within the System Design domain of computer architecture and compiler backends.

On a 4-issue VLIW machine with two ALUs, one load/store unit, and one special-function unit, and with latencies ALU=1 cycle, load=3 cycles, special=2 cycles, schedule a given basic block represented as a dependency DAG to maximize parallel issue and minimize stalls. Produce a legal instruction schedule, explain your handling of hazards and register pressure, discuss software pipelining for a looped version, and describe how your schedule changes if average memory latency increases by one cycle.