[turbofan] Implementation of Word32PairShl on arm.

src/compiler/arm/instruction-selector-arm.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/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 751 matching lines @@
         Emit(kArmSbfx, g.DefineAsRegister(node),
              g.UseRegister(mleft.left().node()), g.TempImmediate(sar - shl),
              g.TempImmediate(32 - sar));
         return;
       }
     }
   }
   VisitShift(this, node, TryMatchASR);
 }
 
-void InstructionSelector::VisitWord32PairShl(Node* node) { UNIMPLEMENTED(); }
+void InstructionSelector::VisitWord32PairShl(Node* node) {
+  ArmOperandGenerator g(this);
+  Int32Matcher m(node->InputAt(2));
+  InstructionOperand shift_operand;
+  if (m.HasValue()) {
+    shift_operand = g.UseImmediate(m.node());
+  } else {
+    shift_operand = g.UseUniqueRegister(m.node());
+  }
+
+  InstructionOperand inputs[] = {g.UseUniqueRegister(node->InputAt(0)),
+                                 g.UseUniqueRegister(node->InputAt(1)),

[ahaas, 2016/03/04 17:20:56]

InputAt(1) and NodeProperties::FindProjection(node, 1) could share a register.
Is it possible to say that in the code?

+                                 shift_operand};
+
+  InstructionOperand outputs[] = {
+      g.DefineAsRegister(node),
+      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+
+  Emit(kArmPairLsl, 2, outputs, 3, inputs);
+}
 
 void InstructionSelector::VisitWord32Ror(Node* node) {
   VisitShift(this, node, TryMatchROR);
 }
 
 
 void InstructionSelector::VisitWord32Clz(Node* node) {
   VisitRR(this, kArmClz, node);
 }
 
@@ skipping 930 matching lines @@
              MachineOperatorBuilder::kFloat64RoundTiesAway |
              MachineOperatorBuilder::kFloat32RoundTiesEven |
              MachineOperatorBuilder::kFloat64RoundTiesEven;
   }
   return flags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8