9.6.3 Dump files and streams

There are two separate output streams available for outputting optimization information from passes. Note that both these streams accept stderr and stdout as valid streams and thus it is possible to dump output to standard output or error. This is specially handy for outputting all available information in a single file by redirecting stderr.

pstream

This stream is for pass-specific dump output. For example, -fdump-tree-vect=foo.v dumps tree vectorization pass output into the given file name foo.v. If the file name is not provided, the default file name is based on the source file and pass number. Note that one could also use special file names stdout and stderr for dumping to standard output and standard error respectively.

alt_stream

This steam is used for printing optimization specific output in response to the -fopt-info. Again a file name can be given. If the file name is not given, it defaults to stderr.