LLVM: Implement UnsignedIntegerToInteger cast

Author: certik

src/libasr/codegen/asr_to_llvm.cpp

@@ -6764,6 +6764,7 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
             case (ASR::cast_kindType::IntegerToUnsignedInteger) : {
                 int arg_kind = -1, dest_kind = -1;
                 extract_kinds(x, arg_kind, dest_kind);
+                LCOMPILERS_ASSERT(arg_kind != -1 && dest_kind != -1)
                 if( arg_kind > 0 && dest_kind > 0 &&
                     arg_kind != dest_kind )
                 {
@@ -6776,7 +6777,18 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
                 break;
             }
             case (ASR::cast_kindType::UnsignedIntegerToInteger) : {
-                // tmp = tmp
+                int arg_kind = -1, dest_kind = -1;
+                extract_kinds(x, arg_kind, dest_kind);
+                LCOMPILERS_ASSERT(arg_kind != -1 && dest_kind != -1)
+                if( arg_kind > 0 && dest_kind > 0 &&
+                    arg_kind != dest_kind )
+                {
+                    if (dest_kind > arg_kind) {
+                        tmp = builder->CreateSExt(tmp, getIntType(dest_kind));
+                    } else {
+                        tmp = builder->CreateTrunc(tmp, getIntType(dest_kind));
+                    }
+                }
                 break;
             }
             case (ASR::cast_kindType::CPtrToUnsignedInteger) : {