added system property to control if-then-else auto retrun type codegen

Author: afernandez90

src/common/IfThenElse.scala

@@ -384,17 +384,28 @@ trait CGenIfThenElse extends CGenEffect with BaseGenIfThenElse {
             emitBlock(b)
             stream.println("}")
           case _ =>
-            val ten = quote(sym) + "True"
-            val fen = quote(sym) + "False"
-            def emitCondFun[T: Manifest](fname: String, block: Block[T]) {
-              stream.println("auto " + fname + " = [&]() {");
-              emitBlock(block)
-              stream.println("return " + quote(getBlockResult(block)) + ";")
-              stream.println("};")
+            if (cppIfElseAutoRet == "true") {
+              val ten = quote(sym) + "True"
+              val fen = quote(sym) + "False"
+              def emitCondFun[T: Manifest](fname: String, block: Block[T]) {
+                stream.println("auto " + fname + " = [&]() {");
+                emitBlock(block)
+                stream.println("return " + quote(getBlockResult(block)) + ";")
+                stream.println("};")
+              }
+              emitCondFun(ten, a)
+              emitCondFun(fen, b) 
+              stream.println("auto " + quote(sym) + " = " + quote(c) + " ? " + ten + "() : " + fen + "();")
+            } else {
+              stream.println("%s %s;".format(remap(sym.tp),quote(sym)))
+              stream.println("if (" + quote(c) + ") {")
+              emitBlock(a)
+              stream.println("%s = %s;".format(quote(sym),quote(getBlockResult(a))))
+              stream.println("} else {")
+              emitBlock(b)
+              stream.println("%s = %s;".format(quote(sym),quote(getBlockResult(b))))
+              stream.println("}")
             }
-            emitCondFun(ten, a)
-            emitCondFun(fen, b)
-            stream.println("auto " + quote(sym) + " = " + quote(c) + " ? " + ten + "() : " + fen + "();")
         }
         /*
         val booll = remap(sym.tp).equals("void")

src/internal/Config.scala

@@ -11,4 +11,7 @@ trait Config {
 
   // explicit return type of lambda functions (allows recursive functions but is less generic)
   val cppExplicitFunRet = System.getProperty("lms.cpp.explicitFunRet","true")
+  
+  // auto return value of if-else expressions (allows type deduction on if-then-else expressions)
+  val cppIfElseAutoRet = System.getProperty("lms.cpp.ifElseAutoRet","false")
 }