Bug 995166 - IonMonkey: Add type policy to MFilterTypeSet, r=jandem

js/src/jit/MIR.h

@@ -9393,7 +9393,8 @@ class MGuardThreadExclusive
 };
 
 class MFilterTypeSet
-  : public MUnaryInstruction
+  : public MUnaryInstruction,
+    public FilterTypeSetPolicy
 {
     MFilterTypeSet(MDefinition *def, types::TemporaryTypeSet *types)
       : MUnaryInstruction(def)
@@ -9411,6 +9412,9 @@ class MFilterTypeSet
         return new(alloc) MFilterTypeSet(def, types);
     }
 
+    TypePolicy *typePolicy() {
+        return this;
+    }
     bool congruentTo(const MDefinition *def) const {
         return false;
     }

js/src/jit/TypePolicy.cpp

@@ -824,3 +824,34 @@ ClampPolicy::adjustInputs(TempAllocator &alloc, MInstruction *ins)
 
     return true;
 }
+
+bool
+FilterTypeSetPolicy::adjustInputs(TempAllocator &alloc, MInstruction *ins)
+{
+    MOZ_ASSERT(ins->numOperands() == 1);
+
+    // Do nothing if already same type.
+    if (ins->type() == ins->getOperand(0)->type())
+        return true;
+
+    // Box input if ouput type is MIRType_Value
+    if (ins->type() == MIRType_Value) {
+        ins->replaceOperand(0, boxAt(alloc, ins, ins->getOperand(0)));
+        return true;
+    }
+
+    // For simplicity just mark output type as MIRType_Value if input type
+    // is MIRType_Value. It should be possible to unbox, but we need to
+    // add extra code for Undefined/Null.
+    if (ins->getOperand(0)->type() == MIRType_Value) {
+        ins->setResultType(MIRType_Value);
+        return true;
+    }
+
+    // In all other cases we will definitely bail, since types don't
+    // correspond. Just box and mark output as MIRType_Value.
+    ins->replaceOperand(0, boxAt(alloc, ins, ins->getOperand(0)));
+    ins->setResultType(MIRType_Value);
+
+    return true;
+}

js/src/jit/TypePolicy.h

@@ -327,6 +327,12 @@ class ClampPolicy : public BoxInputsPolicy
     bool adjustInputs(TempAllocator &alloc, MInstruction *ins);
 };
 
+class FilterTypeSetPolicy : public BoxInputsPolicy
+{
+  public:
+    bool adjustInputs(TempAllocator &alloc, MInstruction *ins);
+};
+
 static inline bool
 CoercesToDouble(MIRType type)
 {