On Dec 20, 2007, Ian Lance Taylor <[EMAIL PROTECTED]> wrote: > Alexandre Oliva <[EMAIL PROTECTED]> writes: >> > How do i know i need to change this DEBUG expression. >> >> As reassoc looks for sets of variables it can freely mess with, it >> should take note of variables that are used in debug annotations in >> addition to the kind of single (?) non-debug uses it's interested in, >> such that, when it modifies these variables, the annotations can be >> compensated for.
> The question is how it finds them efficiently, without doing a scan of > all instructions. It must keep track of variables it can mess with, so it might as well take notes about those it has to be more careful about. *Or* it can just introduce new temporaries, rename the uses and leave the original sets behind for "garbage collection" AKA dead code elimination, like I said. One is more implementation work, the other is potentially more wasteful in terms of memory use. None look particularly hard to me. -- Alexandre Oliva http://www.lsd.ic.unicamp.br/~oliva/ FSF Latin America Board Member http://www.fsfla.org/ Red Hat Compiler Engineer [EMAIL PROTECTED], gcc.gnu.org} Free Software Evangelist [EMAIL PROTECTED], gnu.org}
