We have:
-ftree-loop-distribute-patterns
Perform loop distribution of patterns that can be code generated with calls to a library. This flag is enabled by default at -O2 and higher, and by -fprofile-use and -fauto-profile.
This pass distributes the initialization loops and generates a call to memset zero. For example, the loop
...
and the initialization loop is transformed into a call to memset zero. This flag is enabled by default at -O3. It is also enabled by -fprofile-use and -fauto-profile.
Which mentions optimizatoin flags twice and the repeated mention is out of
date, since we enable this option at -O2 as well.
gcc/ChangeLog:
* doc/invoke.texi (-ftree-loop-distribute-patterns): Remove duplicated
sentence about optimization flags implying this.
ENDDO
@end smallexample
and the initialization loop is transformed into a call to memset zero.
-This flag is enabled by default at @option{-O3}.
-It is also enabled by @option{-fprofile-use} and @option{-fauto-profile}.
@opindex floop-interchange
@item -floop-interchange