[turbofan] Implementation of Word32PairShl on arm.

src/compiler/arm/code-generator-arm.cc

Index: src/compiler/arm/code-generator-arm.cc
diff --git a/src/compiler/arm/code-generator-arm.cc b/src/compiler/arm/code-generator-arm.cc
index 5c94ccf7c3b2d07bb6ce1b379cf99d14135080db..7a11f08b70451eac9999efaace2696bb9c5a017a 100644
--- a/src/compiler/arm/code-generator-arm.cc
+++ b/src/compiler/arm/code-generator-arm.cc
@@ -743,6 +743,15 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ teq(i.InputRegister(0), i.InputOperand2(1));
       DCHECK_EQ(SetCC, i.OutputSBit());
       break;
+    case kArmPairLsl:
+      if (instr->InputAt(2)->IsImmediate()) {
+        __ PairLsl(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
+                   i.InputRegister(1), i.InputInt32(2));
+      } else {
+        __ PairLsl(i.OutputRegister(0), i.OutputRegister(1), i.InputRegister(0),
+                   i.InputRegister(1), kScratchReg, i.InputRegister(2));
+      }
+      break;
     case kArmVcmpF32:
       if (instr->InputAt(1)->IsDoubleRegister()) {
         __ VFPCompareAndSetFlags(i.InputFloat32Register(0),