scc constraint removal can produce empty WL block!
|
|
Bugzilla Link |
756 |
Created on |
Oct 03, 2010 21:45 |
Version |
svn |
OS |
Linux |
Architecture |
PC |
Attachments |
crud.sac |
Extended Description
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.