[tablegen] Fixed few !foreach evaluation issues.

* !foreach on lists didn't evaluate operands of the RHS operator.
  This made nested operators silently fail.
* A typo in the code could result in a wrong value substituted
  for an operation which produced a false '!foreach requires an operator' error.
* Keep recursion over the DAG within ForeachHelper. This simplifies
  things a bit as we no longer need to pass the Type around in order
  to prevent recursion.

Differential Revision: https://reviews.llvm.org/D43083

llvm-svn: 324758
diff --git a/llvm/test/TableGen/foreach-eval.td b/llvm/test/TableGen/foreach-eval.td
new file mode 100644
index 0000000..5bef51e
--- /dev/null
+++ b/llvm/test/TableGen/foreach-eval.td
@@ -0,0 +1,72 @@
+// RUN: llvm-tblgen %s | FileCheck %s
+// XFAIL: vg_leak
+
+// Tests evaluation of !foreach operator.
+
+def d0;
+def d1;
+def d2;
+def d3;
+def d4;
+
+class D<dag d> {
+  int tmp;
+  dag r1 = !foreach(tmp, d, !subst(d1, d0, !subst(d2, d0,
+                                           !subst(d3, d0,
+                                           !subst(d4, d0, tmp)))));
+  dag tmp2;
+  list<dag> dl = [d];
+  list<dag> r2 = !foreach(tmp2, dl,
+                          !foreach(tmp, tmp2, !subst(d1, d0,
+                                              !subst(d2, d0,
+                                              !subst(d3, d0,
+                                              !subst(d4, d0, tmp))))));
+}
+
+// CHECK-LABEL: def d
+// CHECK: dag r1 = (d0 d0, d0, d0, d0);
+// CHECK: list<dag> r2 = [(d0 d0, d0, d0, d0)];
+def d : D <(d0 d1, d2, d3, d4)>;
+
+class I<list<int> i> {
+  int tmp;
+  list<int> r1 = !foreach(tmp, i, !add(3, !add(4, tmp)));
+
+  list<int> tmp2;
+  list<list<int>> li = [i];
+  list<list<int>> r2 = !foreach(tmp2, li,
+                                !foreach(tmp, tmp2, !add(3, !add(4, tmp))));
+}
+
+// CHECK-LABEL: def i
+// CHECK: list<int> r1 = [8, 9, 10];
+// CHECK: list<list<int>> r2 = [{{[[]}}8, 9, 10]];
+def i : I<[1,2,3]>;
+
+class Tmp {
+  dag t0;
+  int t1;
+}
+def tmp: Tmp;
+
+class J0<list<dag> pattern> {
+  list<dag> Pattern = pattern;
+}
+class J1<dag pattern>
+      : J0<[!foreach(tmp.t1, pattern, !subst(d1, d0,
+                                      !subst(d2, d0,
+                                      !subst(d3, d0,
+                                      !subst(d4, d0, tmp.t1)))))]>;
+class J2<list<dag> patterns>
+      : J0<!foreach(tmp.t0, patterns,
+                    !foreach(tmp.t1, tmp.t0, !subst(d1, d0,
+                                             !subst(d2, d0,
+                                             !subst(d3, d0,
+                                             !subst(d4, d0, tmp.t1))))))>;
+// CHECK-LABEL: def j1
+// CHECK: list<dag> Pattern = [(d0 d0:$dst, (d0 d0:$src1))];
+def j1 : J1< (d1 d2:$dst, (d3 d4:$src1))>;
+// CHECK-LABEL: def j2
+// CHECK: list<dag> Pattern = [(d0 d0:$dst, (d0 d0:$src1))];
+def j2 : J2< [(d1 d2:$dst, (d3 d4:$src1))]>;
+