if (exprEffects.contains(EffectSet.EffectType.READ_INTERNAL)) {
// Determine if this expression reads any symbols that are written in the loop.
SymbolSet readSymbols = new SymbolSet(exprEffects.readInternal);
log.debug("ReadSymbols: {}", readSymbols);
readSymbols.retainAll(writtenInLoop);
log.debug("After dropping: {}", readSymbols);
if (!readSymbols.isEmpty()) {
log.debug("No good - reads symbols written in the loop.");
return;