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Re: toolchain/53618: bogus warnings from printf %u and ntohs with -O1 said:
>  This is how it traditionally worked. It does not even depend on
>  optimization level, on big endian CPUs all ntoh* are no-ops. 

Thanks, but I don't understand what you are trying to tell me.

I'm running on X86 so the no-op case shouldn't be happening.  Even if it did 
happen, the argument to ntohs is an unsigned so it shouldn't complain.

There are 4 printfs.  The first is there to make sure that I've got the 
command line switches set to generate this type of warning.  The second is 
there because I was curious.

The last 2 are the interesting ones.  There are no complaints without -O1, but 
warnings with -O1.

If I actually run the code, both produce the same output and it is what I 
Yyy 13
Y13 13
Foo 3328
Bar 3328

3328 == 0xD00 said:
>  this is because the definition of ntohs is
>  #define ntohs(x) (x)
>  in sys/endian.h. 

That's the BYTE_ORDER == BIG_ENDIAN case
I'm running on X86 which is LITTLE_ENDIAN

#define ntohs(x)        bswap16(__CAST(uint16_t, (x)))

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