It's time to do some work on you're compiler. It generates the same code it did 20 years ago. I have to do tricks, instead of writing normal portable code, to get it to generate good code or just use inline assembler. This of course is nothing new, I've been telling you this for almost a decade. Keep in mind that all Intel processors are little endian and that you're compiler generates big endian code, why? You should at least offer a compiler switch to select endianness. Why don't you support C++ and MISRA? Oh and BTW IAR does all of the above TODAY! So clearly they haven't been standing still. (Notice who wrote the paper.)
www.eetimes.com/.../The-Inefficiency-of-C--Fact-or-Fiction-
I have one common header file that I use across 8, 16, 32 and 64 bit processors. My 8051 designs often interact with Windows machines using the same code libraries (AKA portable code). Using each compiler's standard defines with ifdef's some keywords are replaced but the code is the same.