Commit 02c8324294ed4395c1231c6ea3ec6ae77139ba46 caused ATO schema compilation time to jump from about 10 seconds to over 2 minutes. Large increases were also seen in VMF schema compilation.
Some debugging showed that the cause is likely in the DFDLPathExpressionCompiler. Wrapping the following code the compiles an individual expression in a Timer shows an average of 9000% increase in time to compile.
val compiler = new DFDLPathExpressionParser[T](qn,
nodeInfoKind, namespaces, compileInfoWherePropertyWasLocated, isEvaluatedAbove)
val compiledDPath = compiler.compile(expr)
So this most likely has something to do with schema compilation. Nothing jumps out at me in the specified commit as being especially egregious to cause such a performance degredation. All the really changed was passing an extra parameter for error accumulation and changing how isReferencedByExpressions is set. I wouldn't expect that to cause such performance changes. Perhaps it is findNamedMatches now allocating a Seq?