MIPS64: Implemented the RoundUint64ToFloat64 TurboFan operator for x64 and arm64.

Port 857cd4c1

BUG=

Review URL: https://codereview.chromium.org/1439053003

Cr-Commit-Position: refs/heads/master@{#31973}

src/compiler/mips64/code-generator-mips64.cc

@@ -934,6 +934,10 @@ void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
       __ Cvt_d_uw(i.OutputDoubleRegister(), i.InputRegister(0), scratch);
       break;
     }
+    case kMips64CvtDUl: {
+      __ Cvt_d_ul(i.OutputDoubleRegister(), i.InputRegister(0));
+      break;
+    }
     case kMips64TruncWD: {
       FPURegister scratch = kScratchDoubleReg;
       // Other arches use round to zero here, so we follow.

src/compiler/mips64/instruction-codes-mips64.h

@@ -77,6 +77,7 @@ namespace compiler {
   V(Mips64CvtSL)                    \
   V(Mips64CvtDL)                    \
   V(Mips64CvtDUw)                   \
+  V(Mips64CvtDUl)                   \
   V(Mips64Lb)                       \
   V(Mips64Lbu)                      \
   V(Mips64Sb)                       \

src/compiler/mips64/instruction-selector-mips64.cc

@@ -628,7 +628,7 @@ void InstructionSelector::VisitRoundInt64ToFloat64(Node* node) {
 
 
 void InstructionSelector::VisitRoundUint64ToFloat64(Node* node) {
-  UNIMPLEMENTED();
+  VisitRR(this, kMips64CvtDUl, node);
 }
 
 

src/mips64/macro-assembler-mips64.cc

@@ -1542,6 +1542,41 @@ void MacroAssembler::Cvt_d_uw(FPURegister fd,
 }
 
 
+void MacroAssembler::Cvt_d_ul(FPURegister fd, FPURegister fs) {
+  // Move the data from fs to t8.
+  dmfc1(t8, fs);
+  Cvt_d_ul(fd, t8);
+}
+
+
+void MacroAssembler::Cvt_d_ul(FPURegister fd, Register rs) {
+  // Convert rs to a FP value in fd.
+
+  DCHECK(!rs.is(t9));
+  DCHECK(!rs.is(at));
+
+  Label positive, conversion_done;
+
+  Branch(&positive, ge, rs, Operand(zero_reg));
+
+  // Rs >= 2^31.
+  andi(t9, rs, 1);
+  dsrl(rs, rs, 1);
+  or_(t9, t9, rs);
+  dmtc1(t9, fd);
+  cvt_d_l(fd, fd);
+  Branch(USE_DELAY_SLOT, &conversion_done);
+  add_d(fd, fd, fd);  // In delay slot.
+
+  bind(&positive);
+  // Rs < 2^31, we can do simple conversion.
+  dmtc1(rs, fd);
+  cvt_d_l(fd, fd);
+
+  bind(&conversion_done);
+}
+
+
 void MacroAssembler::Round_l_d(FPURegister fd, FPURegister fs) {
   round_l_d(fd, fs);
 }

src/mips64/macro-assembler-mips64.h

@@ -821,6 +821,10 @@ class MacroAssembler: public Assembler {
   void Cvt_d_uw(FPURegister fd, FPURegister fs, FPURegister scratch);
   void Cvt_d_uw(FPURegister fd, Register rs, FPURegister scratch);
 
+  // Convert unsigned long to double.
+  void Cvt_d_ul(FPURegister fd, FPURegister fs);
+  void Cvt_d_ul(FPURegister fd, Register rs);
+
   // Convert double to unsigned long.
   void Trunc_l_ud(FPURegister fd, FPURegister fs, FPURegister scratch);