Add check for unnecessary else statement

cppcheck.rules

@@ -243,6 +243,15 @@
         <summary>The if statement is redundant.</summary>
     </message>
 </rule>
+<rule>
+    <tokenlist>normal</tokenlist>
+    <pattern><![CDATA[if \( [^()]+ \) { [^{}]* (return|throw|break|continue) [^;]* ; } else {]]></pattern>
+    <message>
+        <id>UnnecessaryElseStatement</id>
+        <severity>style</severity>
+        <summary>Else statement is not necessary.</summary>
+    </message>
+</rule>
 <rule>
     <tokenlist>normal</tokenlist>
     <pattern><![CDATA[for \( \w+ (\w+) = \w+ ; \1 < \w+ ; (\1 \+\+|\+\+ \1|\1 \-\-|\-\- \1) \) { \w+ \[ \1 \] = \w+ \[ \1 \] ; }]]></pattern>

test/gpu/miopen.cpp

@@ -35,10 +35,7 @@ std::future<typename std::result_of<Function()>::type> detach_async(Function&& f
         std::thread(std::move(task)).detach();
         return std::move(fut);
     }
-    else
-    {
     return std::async(std::launch::deferred, std::forward<Function>(f));
-    }
 }
 
 struct auto_print