If you do not specify any options when you invoke the Intel® C++ Compiler, the compiler uses the following default settings:
Produces executable output with filename a.o.
Invokes options specified in a configuration file first. See Configuration Files.
Searches for include files using the INCLUDE variable.
Searches for library files in directories specified by the LIB variable, if they are not found in the current directory.
Sets 8 bytes as the strictest alignment constraint for structures.
Displays error and warning messages.
Performs standard optimizations using the default -O2 option, as described in Optimization Choices.
If the compiler does not recognize a command-line option, that option is ignored and a warning is displayed. See Diagnostic Messages for detailed descriptions about system messages.
The vectorizor (-vec) is on by default.