The -xinline option has no effect for optimization levels below -xO3. At -xO4 and higher, the optimizer decides which functions should be inlined, and does so without the -xinline option being specified. At -xO4 and higher, the compiler also attempts to determine which functions will improve performance if they are inlined.
A routine is not inlined if any of the following conditions apply. No warnings will be omitted.
Optimization is less than -xO3
The routine cannot be found
Inlining it is not profitable or safe
The source is not in the file being compiled, or, if you use -xcrossfile[=1], the source is not in the files named on the command line