Conditions for loop unrolling to be beneficial and the point at which margins of return decrease?

循环展开是有益的，在这一点上边际利润下降的情况吗？

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He thinks they'll eventually break up in dissension as competition intensifies and margins decrease.

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This caused an increase in its costs and decrease in its profit margins.

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Third, its margins will improve as its costs decrease and it rolls out more deals with enterprises as opposed to individual consumers.

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