PPC64: Implemented the Word64Clz TurboFan operator.

R=joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com, dstence@us.ibm.com
BUG=

Review URL: https://codereview.chromium.org/1433733002

Cr-Commit-Position: refs/heads/master@{#31903}

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

@@ -944,6 +944,12 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ cntlzw_(i.OutputRegister(), i.InputRegister(0));
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+#if V8_TARGET_ARCH_PPC64
+    case kPPC_Cntlz64:
+      __ cntlzd_(i.OutputRegister(), i.InputRegister(0));
+      DCHECK_EQ(LeaveRC, i.OutputRCBit());
+      break;
+#endif
     case kPPC_Popcnt32:
       __ popcntw(i.OutputRegister(), i.InputRegister(0));
       DCHECK_EQ(LeaveRC, i.OutputRCBit());

src/compiler/ppc/instruction-codes-ppc.h

@@ -62,6 +62,7 @@ namespace compiler {
   V(PPC_MinDouble)                 \
   V(PPC_AbsDouble)                 \
   V(PPC_Cntlz32)                   \
+  V(PPC_Cntlz64)                   \
   V(PPC_Popcnt32)                  \
   V(PPC_Cmp32)                     \
   V(PPC_Cmp64)                     \

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

@@ -737,6 +737,14 @@ void InstructionSelector::VisitWord32Clz(Node* node) {
 }
 
 
+#if V8_TARGET_ARCH_PPC64
+void InstructionSelector::VisitWord64Clz(Node* node) {
+  PPCOperandGenerator g(this);
+  Emit(kPPC_Cntlz64, g.DefineAsRegister(node), g.UseRegister(node->InputAt(0)));
+}
+#endif
+
+
 void InstructionSelector::VisitWord32Popcnt(Node* node) {
   PPCOperandGenerator g(this);
   Emit(kPPC_Popcnt32, g.DefineAsRegister(node),