The options shown in Table 4-23 control compiler optimizations and are described in the sections that follow. The table also indicates whether a compiler license is required to select the optimization level. See Optimizations for a description of the sorts of optimizations possible.
Note that some selections disable optimizations, thus a ‘select all options’ approach will not produce the most compact output.
| Option | License | Builds with |
|---|---|---|
-O0 |
No | Minimal optimizations (default) |
-O
|
No | Optimization level 1 |
-O2 |
No | Optimization level 2 |
-O3 |
Yes | Optimization level 3 |
-Og |
No | Less optimizations for better debugging |
-Os |
Yes | Size-orientated optimizations |
-fasmfile |
No | Optimizations applied to assembly source files |
-f[no-]local |
No | Local optimizations |
--nofallback |
No | Only the selected optimization level and with no license-imposed fall back to a lesser level |