For PR1099:

Partial fix for this PR. Default function parameters to signed integer, just
like everything else in CBE. The bug was caused by incorrectly introducing
parameter attributes feature by choosing "signed" parameter if the
SExtAttribute was specified. Howeer, if no attribute is specified, this
causes it to become unsigned which is incorrect. Reversing the logic so
that signedness is detected by "not ZExtAttribute" set fixes the issue.

This fixes 197.parser but there is more to do. Any comparison and possibly
other operators involving arguments may need to correctly cast the parameter
before its use, depending on the sign of the operator.

llvm-svn: 33034