In this post, we briefly review some of the compiler flags available from the MS IDE.
/Od disables optimization. If you see code that doesn't show locals or functions under a debugger, chances are the compiler has decided to optimize the code. This flag helps with the debugging in that it disables optimizations so that you have access to all code artifacts. This flag has also been used to troubleshoot the compiler.  Compiler can give bad output as well say in one of the following circumstances:
1) a strange combination of compiler flags was used and
2) compiler was asked to build against the incorrect target
In the cases, where the compiler does something weird with the switches specified, the /Od comes to the rescue in providing a single expected version of the executable.
Another thing to mention is that the compiler also provides a /errorReport switch that comes to the use when there are error information report to be generated. This flags is described on the MSDN as one that allows you to provide internal compiler error directly to the Visual C++ team.
The /favor switch helps you to produce code that is optimized for a specific architecture or for micro architectures in both AMD64 and EM64T.
The /GA switch optimizes code for Windows application.
The /GA speeds access to data  declared with the __declspec(thread) in a Windows based program.
The __declspec usually denotes the Microsoft specific storage class attributes such as for example align. What align specifies is that the alignment of user defined data be precisely controlled. This can be used with a struct, union or class  or variables.
The other type of storage attributes include app domain, dllimport, dllexport, noalias, noinline, noreturn, nothrow, novtable, safebuffers, thread etc.
The /Ge switch activates stack probes. This is helpful for stack overflow The same functionality is now available via /Gs  and is preferred over the now deprecated /Ge switch.
The /GF switch enables string pooling that can create smaller programs. /GF is in effect when /O1 or /O2 is used.
The /GL switch enables whole program optimization. Much of these optimizations are also described by the /LTCG option LTCG stands for Link time code generation and is responsible for optimizations such as
cross module inlining
inter procedural register  allocation on 64bit
custom calling convention (on x86 only)
Small TLS displacement (on x86 only)
Stack double alignment(x86 only)
and disambiguation between global variables and input parameters.
/Wp64 compiler option detects portability problems
It does this by testing the usages of int, long and pointer in the program.  If the 64bit compiler is regularly used, this flag can be disabled because the compiler will detect all such issues.
By default, this is off in 32 bit compilers and on in the 64 bit compilers.
Lastly, we discuss the  /Zi  option that generates complete debugging information. This option implies the /DEBUG (generate debug information) Note that this only affects the program database PDB  where the compiler puts the debugging information.
/GT option supports fiber safety for data allocated using static thread-local storage.
The opposite of disabled optimization is full optimization which is specified by the /Ox maximum optimization (/Ob2gity /Gs)