cranelift: Add fadd/fsub/fmul/fdiv to interpreter (#4446)

Fuzzgen found these as soon as I added float support

cranelift/interpreter/src/value.rs

@@ -18,6 +18,7 @@ pub trait Value: Clone + From<DataValue> {
     fn into_int(self) -> ValueResult<i128>;
     fn float(n: u64, ty: Type) -> ValueResult<Self>;
     fn into_float(self) -> ValueResult<f64>;
+    fn is_float(&self) -> bool;
     fn is_nan(&self) -> ValueResult<bool>;
     fn bool(b: bool, ty: Type) -> ValueResult<Self>;
     fn into_bool(self) -> ValueResult<bool>;
@@ -250,6 +251,13 @@ impl Value for DataValue {
         unimplemented!()
     }
 
+    fn is_float(&self) -> bool {
+        match self {
+            DataValue::F32(_) | DataValue::F64(_) => true,
+            _ => false,
+        }
+    }
+
     fn is_nan(&self) -> ValueResult<bool> {
         match self {
             DataValue::F32(f) => Ok(f.is_nan()),
@@ -457,19 +465,34 @@ impl Value for DataValue {
     }
 
     fn add(self, other: Self) -> ValueResult<Self> {
-        // TODO: floats must handle NaNs, +/-0
-        binary_match!(wrapping_add(&self, &other); [I8, I16, I32, I64, I128, U8, U16, U32, U64, U128])
+        if self.is_float() {
+            binary_match!(+(self, other); [F32, F64])
+        } else {
+            binary_match!(wrapping_add(&self, &other); [I8, I16, I32, I64, I128, U8, U16, U32, U64, U128])
+        }
     }
 
     fn sub(self, other: Self) -> ValueResult<Self> {
-        binary_match!(wrapping_sub(&self, &other); [I8, I16, I32, I64, I128]) // TODO: floats must handle NaNs, +/-0
+        if self.is_float() {
+            binary_match!(-(self, other); [F32, F64])
+        } else {
+            binary_match!(wrapping_sub(&self, &other); [I8, I16, I32, I64, I128])
+        }
     }
 
     fn mul(self, other: Self) -> ValueResult<Self> {
-        binary_match!(wrapping_mul(&self, &other); [I8, I16, I32, I64, I128])
+        if self.is_float() {
+            binary_match!(*(self, other); [F32, F64])
+        } else {
+            binary_match!(wrapping_mul(&self, &other); [I8, I16, I32, I64, I128])
+        }
     }
 
     fn div(self, other: Self) -> ValueResult<Self> {
+        if self.is_float() {
+            return binary_match!(/(self, other); [F32, F64]);
+        }
+
         let denominator = other.clone().into_int()?;
 
         // Check if we are dividing INT_MIN / -1. This causes an integer overflow trap.