When all operands or results are variadic, zero values is a perfectly valid behavior
to expect, and we shouldn't force the user to provide values in this case. For example,
when creating a call or a return operation we often don't want/need to provide return
values.
Differential Revision: https://reviews.llvm.org/D133721
Up until now PDL(L) has not supported dialect conversion because we had no
way of remapping values or integrating with type conversions. This commit
rectifies that by adding a new "pattern configuration" concept to PDL. This
essentially allows for attaching external configurations to patterns, which
can hook into pattern events (for now just the scope of a rewrite, but we
could also pass configs to native rewrites as well). This allows for injecting
the type converter into the conversion pattern rewriter.
Differential Revision: https://reviews.llvm.org/D133142
