scc constraint removal can produce empty WL block!
|Created on||Oct 03, 2010 21:45|
In the attached, compiling with: sac2c-d crud.sac -O3 -doawlf -nowlf -extrema -ecc -v1 for build #developer rev 17069:MODIFIED causes a crash in EBT after SCC. It looks like the problem is that SCC blindly eliminates code from a block, but this can (and does, in this case) result it removing the last piece of code from an N_with code block, which is verboten. I think the fix is to put some code in SCCblock to check for this and insert the canonical EMPTY marker if the block does become empty.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information