------- Comment #2 from rguenther at suse dot de 2009-07-14 21:28 ------- Subject: Re: SRA scalarizes dead objects, single-use objects
On Tue, 14 Jul 2009, jamborm at gcc dot gnu dot org wrote: > ------- Comment #1 from jamborm at gcc dot gnu dot org 2009-07-14 16:32 > ------- > OK, I have now added this to my todo list. The simple tweaks would be > simple. On the other hand, if DCE is clever, it still might figure > out a structure is dead at some code paths while I don't even attempt > to and still remove some statements. > > > only loads from a structure or only stores to a structure > > probably should be simply skipped. > > I've been thinking about not scalarizing accesses that occur only once > too. Thinking about it more, I wonder whether requiring at least one > load and a store or at least two loads is a good idea. (Load and > store for the case where we store something to an aggregate first and > then load it and two loads for the case when we can finally get away > with one.) Note that it is important to keep the structure copyprop case tmp = b; return tmp; which happens quite often in C++ code. Richard. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40744
