[turbofan] Support variable size argument popping in TF-generated functions

test/unittests/compiler/branch-elimination-unittest.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/branch-elimination.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-properties.h"
 #include "test/unittests/compiler/compiler-test-utils.h"
 #include "test/unittests/compiler/graph-unittest.h"
@@ skipping 47 matching lines @@
       graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
                        Int32Constant(1), Int32Constant(2), inner_merge);
 
   Node* outer_if_false = graph()->NewNode(common()->IfFalse(), outer_branch);
   Node* outer_merge =
       graph()->NewNode(common()->Merge(2), inner_merge, outer_if_false);
   Node* outer_phi =
       graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
                        inner_phi, Int32Constant(3), outer_merge);
 
-  Node* ret = graph()->NewNode(common()->Return(), outer_phi, graph()->start(),
-                               outer_merge);
+  Node* zero = graph()->NewNode(common()->Int32Constant(0));
+  Node* ret = graph()->NewNode(common()->Return(), zero, outer_phi,
+                               graph()->start(), outer_merge);
   graph()->SetEnd(graph()->NewNode(common()->End(1), ret));
 
   Reduce();
 
   // Outer branch should not be rewritten, the inner branch should be discarded.
   EXPECT_THAT(outer_branch, IsBranch(condition, graph()->start()));
   EXPECT_THAT(inner_phi,
               IsPhi(MachineRepresentation::kWord32, IsInt32Constant(1),
                     IsInt32Constant(2), IsMerge(outer_if_true, IsDead())));
 }
@@ skipping 19 matching lines @@
   Node* inner_phi =
       graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
                        Int32Constant(2), Int32Constant(3), inner_merge);
 
   Node* outer_merge =
       graph()->NewNode(common()->Merge(2), outer_if_true, inner_merge);
   Node* outer_phi =
       graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
                        Int32Constant(1), inner_phi, outer_merge);
 
-  Node* ret = graph()->NewNode(common()->Return(), outer_phi, graph()->start(),
-                               outer_merge);
+  Node* zero = graph()->NewNode(common()->Int32Constant(0));
+  Node* ret = graph()->NewNode(common()->Return(), zero, outer_phi,
+                               graph()->start(), outer_merge);
   graph()->SetEnd(graph()->NewNode(common()->End(1), ret));
 
   Reduce();
 
   // Outer branch should not be rewritten, the inner branch should be discarded.
   EXPECT_THAT(outer_branch, IsBranch(condition, graph()->start()));
   EXPECT_THAT(inner_phi,
               IsPhi(MachineRepresentation::kWord32, IsInt32Constant(2),
                     IsInt32Constant(3), IsMerge(IsDead(), outer_if_false)));
 }
@@ skipping 16 matching lines @@
   Node* branch2 = graph()->NewNode(common()->Branch(), condition, merge1);
   Node* if_true2 = graph()->NewNode(common()->IfTrue(), branch2);
   Node* if_false2 = graph()->NewNode(common()->IfFalse(), branch2);
   Node* merge2 = graph()->NewNode(common()->Merge(2), if_true2, if_false2);
   Node* phi2 =
       graph()->NewNode(common()->Phi(MachineRepresentation::kWord32, 2),
                        Int32Constant(3), Int32Constant(4), merge1);
 
 
   Node* add = graph()->NewNode(machine()->Int32Add(), phi1, phi2);
+  Node* zero = graph()->NewNode(common()->Int32Constant(0));
   Node* ret =
-      graph()->NewNode(common()->Return(), add, graph()->start(), merge2);
+      graph()->NewNode(common()->Return(), zero, add, graph()->start(), merge2);
   graph()->SetEnd(graph()->NewNode(common()->End(1), ret));
 
   Reduce();
 
   // Outer branch should not be rewritten, the inner branch condition should
   // be true.
   EXPECT_THAT(branch1, IsBranch(condition, graph()->start()));
   EXPECT_THAT(branch2, IsBranch(condition, merge1));
 }
 
@@ skipping 10 matching lines @@
   Node* outer_if_true = graph()->NewNode(common()->IfTrue(), outer_branch);
 
 
   Node* loop = graph()->NewNode(common()->Loop(1), outer_if_true);
   Node* effect =
       graph()->NewNode(common()->EffectPhi(1), graph()->start(), loop);
 
   Node* inner_branch = graph()->NewNode(common()->Branch(), condition, loop);
 
   Node* inner_if_true = graph()->NewNode(common()->IfTrue(), inner_branch);
-  Node* ret1 = graph()->NewNode(common()->Return(), Int32Constant(2), effect,
-                                inner_if_true);
+  Node* zero = graph()->NewNode(common()->Int32Constant(0));
+  Node* ret1 = graph()->NewNode(common()->Return(), zero, Int32Constant(2),
+                                effect, inner_if_true);
 
   Node* inner_if_false = graph()->NewNode(common()->IfFalse(), inner_branch);
   loop->AppendInput(zone(), inner_if_false);
   NodeProperties::ChangeOp(loop, common()->Loop(2));
   effect->InsertInput(zone(), 1, effect);
   NodeProperties::ChangeOp(effect, common()->EffectPhi(2));
 
   Node* outer_if_false = graph()->NewNode(common()->IfFalse(), outer_branch);
   Node* outer_merge =
       graph()->NewNode(common()->Merge(2), loop, outer_if_false);
   Node* outer_ephi = graph()->NewNode(common()->EffectPhi(2), effect,
                                       graph()->start(), outer_merge);
 
-  Node* ret2 = graph()->NewNode(common()->Return(), Int32Constant(1),
+  Node* ret2 = graph()->NewNode(common()->Return(), zero, Int32Constant(1),
                                 outer_ephi, outer_merge);
 
   Node* terminate = graph()->NewNode(common()->Terminate(), effect, loop);
   graph()->SetEnd(graph()->NewNode(common()->End(3), ret1, ret2, terminate));
 
   Reduce();
 
   // Outer branch should not be rewritten, the inner branch should be discarded.
   EXPECT_THAT(outer_branch, IsBranch(condition, graph()->start()));
   EXPECT_THAT(ret1, IsReturn(IsInt32Constant(2), effect, loop));
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8