Please sign in to comment.
Add an OutPatFrag TableGen class
Unfortunately, it is currently impossible to use a PatFrag as part of an output pattern (the part of the pattern that has instructions in it) in TableGen. Looking at the current implementation, this was clearly intended to work (there is already code in place to expand patterns in the output DAG), but is currently broken by the baked-in type-checking assumption and the order in which the pattern fragments are processed (output pattern fragments need to be processed after the instruction definitions are processed). Fixing this is fairly simple, but requires some way of differentiating output patterns from the existing input patterns. The simplest way to handle this seems to be to create a subclass of PatFrag, and so that's what I've done here. As a simple example, this allows us to write: def crnot : OutPatFrag<(ops node:$in), (CRNOR $in, $in)>; def : Pat<(not i1:$in), (crnot $in)>; which captures the core use case: handling of repeated subexpressions inside of complicated output patterns. This will be used by an upcoming commit to the PowerPC backend. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202450 91177308-0d34-0410-b5e6-96231b3b80d8
- Loading branch information...
Showing with 22 additions and 5 deletions.