[GENERAL] Various improvements:

* Sparse einsum in triton.ops.einsum
* Hacky support for fixed-tile-size atomic-add
* Various bugfixes in parser

lib/lang/parser.cc

@@ -650,7 +650,7 @@ Expr* Parser::ParseDerefOp(const Token* tok) {
   Expr* pred = nullptr;
   if(ts_.Try('?')){
     ts_.Expect('(');
-    pred = ParseCastExpr();
+    pred = ParseExpr();
     ts_.Expect(')');
   }
   Expr* addr = ParseCastExpr();