translator: add while block, tests

translator/src/main/kotlin/org/kotlinnative/translator/BlockCodegen.kt

@@ -856,7 +856,10 @@ abstract class BlockCodegen(val state: TranslationState, val variableManager: Va
             successExpression = codeBuilder.loadAndGetVariable(successExpression)
         }
 
-        codeBuilder.storeVariable(resultVariable, successExpression ?: return)
+        if (successExpression != null) {
+            codeBuilder.storeVariable(resultVariable, successExpression)
+        }
+
         codeBuilder.addUnconditionalJump(endLabel)
         codeBuilder.addComment("end last condition item")
     }
@@ -870,7 +873,7 @@ abstract class BlockCodegen(val state: TranslationState, val variableManager: Va
         val targetExpression = evaluateExpression(whenExpression, scopeDepth + 1)!!
         val resultVariable = codeBuilder.getNewVariable(expressionType, pointer = 1)
 
-        if (expressionType !is LLVMVoidType) {
+        if (expressionType !is LLVMVoidType && expressionType !is LLVMNullType) {
             codeBuilder.allocStackPointedVarAsValue(resultVariable)
         }
 

translator/src/test/kotlin/tests/input/when_block.txt

@@ -0,0 +1,3 @@
+when_block_test1_Int(0) == 1
+when_block_test1_Int(1) == 0
+when_block_test1_Int(2) == 0

translator/src/test/kotlin/tests/kotlin/when_block.kt

@@ -0,0 +1,9 @@
+
+fun when_block_test1(i: Int): Boolean {
+    when (i) {
+        0 -> return true
+        1 -> return false
+    }
+
+    return false
+}