Some Problematic Code Practices

Any of the following coding practices, and many others, could cause problems with an optimization level of -O3 or -O4:

• A program unit does arithmetic with the pointer.

• A subprogram saves the address of any of its arguments between calls.

• A function returns the address of any of its arguments, although it can return the value of a pointer argument.

• A variable is referenced through a pointer, but the address of the variable is not explicitly taken with the LOC() or MALLOC() functions.

Example: Code that could cause trouble with -O3 or -O4:

	COMMON A, B, C 
	POINTER ( P, V ) 
	P = LOC(A) + 4 			  Possible problems here if optimized
	... 

The compiler assumes that a reference through P may change A, but not B; this assumption could produce incorrect code.