Texas Instruments TMS320C2x, User Manual

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Using the − o3 Option
3-4
3.2 Using the − o3 Option
The − o3 option instructs the compiler to perform file-level optimization. You
can use the − o3 option alone to perform general file-level optimization, or you
can combine it with other options to perform more specific optimizations. The
options listed in Table 3
− 1 work with − o3 to perform the indicated optimization:
Table 3 − 1. Options That You Can Use With − o3
If you ... Use this option Page
Have files that redeclare standard library functions − ol n 3-4
Want to create an optimization information file − on n 3-5
Want to compile multiple source files − pm 3-6
3.2.1 Controlling File-Level Optimization ( − ol n Option)
When you invoke the optimizer with the − o3 option, some of the optimizations
use known properties of the standard library functions. If your file redeclares
any of these standard library functions, these optimizations become ineffec-
tive. The
− ol (lowercase L) option controls file-level optimizations. The number
following the − ol denotes the level (0, 1, or 2). Use Table 3 − 2 to select the ap-
propriate level to append to the − ol option.
Table 3 − 2. Selecting a Level for the − ol Option
If your source file... Use this option
Declares a function with the same name as a standard library
function − ol0
Contains but does not alter functions declared in the standard li-
brary − ol1
Does not alter standard library functions, but you used the − ol0
or − ol1 option in a command file or an environment variable. The
− ol2 option restores the default behavior of the optimizer.
− ol2