gcc -O3 -fopt-info-missed=missed.all
outputs missed optimization report from all the passes into missed.all.
As another example,
gcc -O3 -fopt-info-inline-optimized-missed=inline.txt
will output information about missed optimizations as well as optimized locations from all the inlining passes into inline.txt.
If the filename is provided, then the dumps from all the applicable optimizations are concatenated into the filename. Otherwise the dump is output onto stderr. If options is omitted, it defaults to optimized-optall, which means dump all information about successful optimizations from all the passes. In the following example, the optimization information is output on to stderr.
gcc -O3 -fopt-info
Note that -fopt-info-vec-missed behaves the same as -fopt-info-missed-vec. The order of the optimization group names and message types listed after -fopt-info does not matter.
As another example, consider
gcc -fopt-info-vec-missed=vec.miss -fopt-info-loop-optimized=loop.opt
Here the two output file names vec.miss and loop.opt are in conflict since only one output file is allowed. In this case, only the first option takes effect and the subsequent options are ignored. Thus only the vec.miss is produced which containts dumps from the vectorizer about missed opportunities.