AR# 13109: 4.1i Virtex-II MAP - An unused multiplier is not trimmed, and a pack error occurs
4.1i Virtex-II MAP - An unused multiplier is not trimmed, and a pack error occurs
Keywords: multiplier, trimmed, trimming, unused
General Description: My design contains a multiplier whose outputs drive logic that is ultimately unused. In version 3.1i, all of this logic, including the multiplier, was trimmed. In 4.1i, the multiplier is not being trimmed and MAP fails with the following error:
ERROR:Pack - Symbol "mult_shifter/multiplier_block_a1_b1/mult18x18" has no output pin connections.
To work around this problem, block the trimming of one multiplier output net with a UCF constraint:
NET "mult_shifter/multiplier_block_a1_b1_out<0>" S ;