PPC: [turbofan] Enable tail calls for %_CallRuntime.

src/compiler/ppc/instruction-selector-ppc.cc

 // Copyright 2014 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/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
@@ skipping 1502 matching lines @@
 
 
 void InstructionSelector::VisitTailCall(Node* node) {
   PPCOperandGenerator g(this);
   CallDescriptor const* descriptor = OpParameter<CallDescriptor const*>(node);
   DCHECK_NE(0, descriptor->flags() & CallDescriptor::kSupportsTailCalls);
   DCHECK_EQ(0, descriptor->flags() & CallDescriptor::kPatchableCallSite);
   DCHECK_EQ(0, descriptor->flags() & CallDescriptor::kNeedsNopAfterCall);
 
   // TODO(turbofan): Relax restriction for stack parameters.
-  if (descriptor->UsesOnlyRegisters() &&
-      descriptor->HasSameReturnLocationsAs(
-          linkage()->GetIncomingDescriptor())) {
+  if (linkage()->GetIncomingDescriptor()->CanTailCall(node)) {
     CallBuffer buffer(zone(), descriptor, nullptr);
 
     // Compute InstructionOperands for inputs and outputs.
     // TODO(turbofan): on PPC it's probably better to use the code object in a
     // register if there are multiple uses of it. Improve constant pool and the
     // heuristics in the register allocator for where to emit constants.
     InitializeCallBuffer(node, &buffer, true, false);
 
-    DCHECK_EQ(0u, buffer.pushed_nodes.size());
-
     // Select the appropriate opcode based on the call type.
     InstructionCode opcode;
     switch (descriptor->kind()) {
       case CallDescriptor::kCallCodeObject:
         opcode = kArchTailCallCodeObject;
         break;
       case CallDescriptor::kCallJSFunction:
         opcode = kArchTailCallJSFunction;
         break;
       default:
@@ skipping 102 matching lines @@
 InstructionSelector::SupportedMachineOperatorFlags() {
   return MachineOperatorBuilder::kFloat64RoundDown |
          MachineOperatorBuilder::kFloat64RoundTruncate |
          MachineOperatorBuilder::kFloat64RoundTiesAway;
   // We omit kWord32ShiftIsSafe as s[rl]w use 0x3f as a mask rather than 0x1f.
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8