[intrinsics] Kill the %_IsMinusZero intrinsic.

src/crankshaft/mips64/lithium-codegen-mips64.cc

Index: src/crankshaft/mips64/lithium-codegen-mips64.cc
diff --git a/src/crankshaft/mips64/lithium-codegen-mips64.cc b/src/crankshaft/mips64/lithium-codegen-mips64.cc
index b0fd0952ce7b125281d41b675b154589e1ccd1aa..26c368e1794db66246ab7defe17ab65ba54c1a66 100644
--- a/src/crankshaft/mips64/lithium-codegen-mips64.cc
+++ b/src/crankshaft/mips64/lithium-codegen-mips64.cc
@@ -2338,35 +2338,6 @@ void LCodeGen::DoCmpHoleAndBranch(LCmpHoleAndBranch* instr) {
 }
 
 
-void LCodeGen::DoCompareMinusZeroAndBranch(LCompareMinusZeroAndBranch* instr) {
-  Representation rep = instr->hydrogen()->value()->representation();
-  DCHECK(!rep.IsInteger32());
-  Register scratch = ToRegister(instr->temp());
-
-  if (rep.IsDouble()) {
-    DoubleRegister value = ToDoubleRegister(instr->value());
-    EmitFalseBranchF(instr, ne, value, kDoubleRegZero);
-    __ FmoveHigh(scratch, value);
-    // Only use low 32-bits of value.
-    __ dsll32(scratch, scratch, 0);
-    __ dsrl32(scratch, scratch, 0);
-    __ li(at, 0x80000000);
-  } else {
-    Register value = ToRegister(instr->value());
-    __ CheckMap(value,
-                scratch,
-                Heap::kHeapNumberMapRootIndex,
-                instr->FalseLabel(chunk()),
-                DO_SMI_CHECK);
-    __ lwu(scratch, FieldMemOperand(value, HeapNumber::kExponentOffset));
-    EmitFalseBranch(instr, ne, scratch, Operand(0x80000000));
-    __ lwu(scratch, FieldMemOperand(value, HeapNumber::kMantissaOffset));
-    __ mov(at, zero_reg);
-  }
-  EmitBranch(instr, eq, scratch, Operand(at));
-}
-
-
 Condition LCodeGen::EmitIsString(Register input,
                                  Register temp1,
                                  Label* is_not_string,