Failed in dbfixup.py:153 add_tag_bits (AssertionError) because the
process_rdb name-harmonisation loop folded two distinct-bit Y1 IN
groups onto a single feature name. On Virtex-7 IOB_Y1 LVCMOS*.IN
has bits {38_00,39_01} but SSTL*.IN has only {38_00}; the visited-
iostandard logic forced both onto 'LVCMOS18_SSTL12_SSTL135_SSTL15.IN'
(driven by the Y0 grouping where they happened to share bits),
emitting two contradictory db lines that dbfixup can't merge.
(The existing filter_negbits already expects the un-merged name
IOB_Y1.LVCMOS12_LVCMOS15_LVCMOS18.IN, confirming the merge is wrong
here.) kintex7's Y1 LVCMOS and SSTL share bits, so it never hits
this case.
Fix: require identical bits before adopting a visited name; gate
via XRAY_DATABASE == virtex7 so kintex7's behaviour is provably
unchanged. Adds 'import os' for the env check.
Verified: no duplicate tags; Y1 splits correctly into
LVCMOS12_LVCMOS15_LVCMOS18.IN + SSTL12_SSTL135_SSTL15.IN.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Dr Jonathan Richard Robert Kimmitt
Hans Baier