Why is /Wp64 deprecated?

Question

Why is the /Wp64 flag in Visual C++ deprecated?

cl : Command line warning D9035 :
option \'Wp64\' has been deprecated and will be r

Answer 1

Because when using the 64 Bit compiler from VS2010 the compiler does the detection of 64 bit problems automatically... this switch is from back in the day when you could try to detect 64 Bit problem running the 32 Bit compiler...

See http://msdn.microsoft.com/en-us/library/yt4xw8fh%28v=VS.100%29.aspx