This invention modifies an irregular software pipelined loop conditioned
upon data in a condition register in a compiler scheduled very long
instruction word data processor to prevent over-execution upon loop exit.
The method replaces a register modifying instruction with an instruction
conditional upon the inverse condition register if possible. The method
inserts a conditional register move instruction to a previously unused
register within the loop if possible without disturbing the schedule.
Then a restoring instruction is added after the loop. Alternatively, both
these two functions can be performed by a delayed register move
instruction. Instruction insertion is into a previously unused
instruction slot of an execute packet. These changes can be performed
manually or automatically by the compiler.