On Tue, May 28, 2024 at 9:46 PM Harald Anlauf <anl...@gmx.de> wrote: > > Hi Andre, > > On 5/28/24 14:10, Andre Vehreschild wrote: > > Hi all, > > > > the attached patch fixes a memory leak with unlimited polymorphic return > > types. > > The leak occurred, because an expression with side-effects was evaluated > > twice. > > I have substituted the check for non-variable expressions followed by > > creating a > > SAVE_EXPR with checking for trees with side effects and creating temp. > > variable > > and freeing the memory. > > this looks good to me. It also solves the runtime memory leak in > testcase pr114012.f90 . Nice! > > > Btw, I do not get the SAVE_EXPR in the old code. Is there something missing > > to > > manifest it or is a SAVE_EXPR not meant to be evaluated twice? > > I was assuming that the comment in gcc/tree.h applies here: > > /* save_expr (EXP) returns an expression equivalent to EXP > but it can be used multiple times within context CTX > and only evaluate EXP once. */ > > I do not know what the practical difference between a SAVE_EXPR > and a temporary explicitly evaluated once (which you have now) > is, except that you can free the temporary cleanly.
A SAVE_EXPR is turned into the latter - a temporary plus once evaluated side-effects - by the gimplifier. It's sometimes more convenient to use a SAVE_EXPR but an IMO an explicit temporary is prefered. Note SAVE_EXPRs have to be used from the same "evaluation context", when you use the SAVE_EXPR from two different statements it's by chance the temporary is initialized by the earlier one and not by the later and used uninitialized by the earlier. That means SAVE_EXPRs are to be used from within a single (large) expression. > > Anyway, regtested ok on Linux-x86_64-Fedora_39. Ok for master? > > Yes, this is fine from my side. If you are inclined to backport > to e.g. 14-branch after a grace period, that would be great. > > > This work is funded by the Souvereign Tech Fund. Yes, the funding has been > > granted and Nicolas, Mikael and me will be working on some Fortran topics in > > the next 12-18 months. > > This is really great news! > > > Regards, > > Andre > > Thanks for the patch! > > Harald > > > -- > > Andre Vehreschild * Email: vehre ad gmx dot de >
