PPC: [turbofan] Added the RoundInt64ToFloat64 instruction to TurboFan.

Port 870e908d

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

Review URL: https://codereview.chromium.org/1428133002

Cr-Commit-Position: refs/heads/master@{#31795}

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

@@ -1031,6 +1031,10 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ Move(i.OutputRegister(), i.InputRegister(0));
       DCHECK_EQ(LeaveRC, i.OutputRCBit());
       break;
+    case kPPC_Int64ToDouble:
+      __ ConvertInt64ToDouble(i.InputRegister(0), i.OutputDoubleRegister());
+      DCHECK_EQ(LeaveRC, i.OutputRCBit());
+      break;
 #endif
     case kPPC_Int32ToDouble:
       __ ConvertIntToDouble(i.InputRegister(0), i.OutputDoubleRegister());

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

@@ -76,6 +76,7 @@ namespace compiler {
   V(PPC_ExtendSignWord32)          \
   V(PPC_Uint32ToUint64)            \
   V(PPC_Int64ToInt32)              \
+  V(PPC_Int64ToDouble)             \
   V(PPC_Int32ToDouble)             \
   V(PPC_Uint32ToDouble)            \
   V(PPC_Float32ToDouble)           \

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

@@ -917,6 +917,11 @@ void InstructionSelector::VisitTruncateInt64ToInt32(Node* node) {
   // TODO(mbrandy): inspect input to see if nop is appropriate.
   VisitRR(this, kPPC_Int64ToInt32, node);
 }
+
+
+void InstructionSelector::VisitRoundInt64ToFloat64(Node* node) {
+  VisitRR(this, kPPC_Int64ToDouble, node);
+}
 #endif
 
 

src/ppc/macro-assembler-ppc.cc

@@ -664,6 +664,15 @@ void MacroAssembler::ConvertIntToFloat(const DoubleRegister dst,
 }
 
 
+#if V8_TARGET_ARCH_PPC64
+void MacroAssembler::ConvertInt64ToDouble(Register src,
+                                          DoubleRegister double_dst) {
+  MovInt64ToDouble(double_dst, src);
+  fcfid(double_dst, double_dst);
+}
+#endif
+
+
 void MacroAssembler::ConvertDoubleToInt64(const DoubleRegister double_input,
 #if !V8_TARGET_ARCH_PPC64
                                           const Register dst_hi,

src/ppc/macro-assembler-ppc.h

@@ -386,6 +386,10 @@ class MacroAssembler : public Assembler {
   void ConvertIntToFloat(const DoubleRegister dst, const Register src,
                          const Register int_scratch);
 
+#if V8_TARGET_ARCH_PPC64
+  void ConvertInt64ToDouble(Register src, DoubleRegister double_dst);
+#endif
+
   // Converts the double_input to an integer.  Note that, upon return,
   // the contents of double_dst will also hold the fixed point representation.
   void ConvertDoubleToInt64(const DoubleRegister double_input,