MIPS: Never hchange nan-hole to hole or hole to nan-hole. Only allow changing hole to nan if all us…

src/mips/lithium-mips.h

Index: src/mips/lithium-mips.h
diff --git a/src/mips/lithium-mips.h b/src/mips/lithium-mips.h
index a1792b17b22bdd3924d3a371ce8dc4367ffc11d7..4bf904970e331d91039a0569e79231c21bf65071 100644
--- a/src/mips/lithium-mips.h
+++ b/src/mips/lithium-mips.h
@@ -74,6 +74,7 @@ class LCodeGen;
   V(ClassOfTestAndBranch)                       \
   V(CompareNumericAndBranch)                    \
   V(CmpObjectEqAndBranch)                       \
+  V(CmpHoleAndBranch)                           \
   V(CmpMapAndBranch)                            \
   V(CmpT)                                       \
   V(ConstantD)                                  \
@@ -887,12 +888,24 @@ class LCmpObjectEqAndBranch: public LControlInstruction<2, 0> {
   LOperand* left() { return inputs_[0]; }
   LOperand* right() { return inputs_[1]; }
 
-  DECLARE_CONCRETE_INSTRUCTION(CmpObjectEqAndBranch,
-                               "cmp-object-eq-and-branch")
+  DECLARE_CONCRETE_INSTRUCTION(CmpObjectEqAndBranch, "cmp-object-eq-and-branch")
   DECLARE_HYDROGEN_ACCESSOR(CompareObjectEqAndBranch)
 };
 
 
+class LCmpHoleAndBranch: public LControlInstruction<1, 0> {
+ public:
+  explicit LCmpHoleAndBranch(LOperand* object) {
+    inputs_[0] = object;
+  }
+
+  LOperand* object() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(CmpHoleAndBranch, "cmp-hole-and-branch")
+  DECLARE_HYDROGEN_ACCESSOR(CompareHoleAndBranch)
+};
+
+
 class LIsObjectAndBranch: public LControlInstruction<1, 1> {
  public:
   LIsObjectAndBranch(LOperand* value, LOperand* temp) {