On Thu, Jun 04, 2015 at 12:26:03PM +0000, Joseph Myers wrote:
> > Again is this worth a gcc pass?
>
> This isn't a matter of compiler passes; it's additional checks in existing
> built-in function handling. Maybe that built-in function handling should
> move to the match-and-simplify infrastructure (some, for libm functions
> and bswap, already has) to make this even simpler to implement.
GCC already has a pass that attempts to track known and earlier computed
lengths of strings, and do various transformations and optimizations based
on that, see the tree-ssa-strlen.c pass. Most of that you really can't do
at the glibc headers level.
Jakub
