Add the optimization in a few other methods

Author: antoyo

src/builder.rs

@@ -855,18 +855,21 @@ impl<'a, 'gcc, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'gcc, 'tcx> {
     }
 
     fn neg(&mut self, a: RValue<'gcc>) -> RValue<'gcc> {
-        set_rvalue_location(self, self.gcc_neg(a))
+        let result = set_rvalue_location(self, self.gcc_neg(a));
+        self.assign_to_var(result)
     }
 
     fn fneg(&mut self, a: RValue<'gcc>) -> RValue<'gcc> {
-        set_rvalue_location(
+        let result = set_rvalue_location(
             self,
             self.cx.context.new_unary_op(self.location, UnaryOp::Minus, a.get_type(), a),
-        )
+        );
+        self.assign_to_var(result)
     }
 
     fn not(&mut self, a: RValue<'gcc>) -> RValue<'gcc> {
-        set_rvalue_location(self, self.gcc_not(a))
+        let result = set_rvalue_location(self, self.gcc_not(a));
+        self.assign_to_var(result)
     }
 
     fn fadd_fast(&mut self, lhs: RValue<'gcc>, rhs: RValue<'gcc>) -> RValue<'gcc> {