On Sep 3, 2013, at 9:53 AM, Rafael Espíndola <[email protected]> wrote:
>>> This is something Chris requested, IIRC. I'm not sure I remember the >>> motivation beyond that. >> >> Two reasons: >> >> 1) -O1 doesn't actually mean anything. It is the optimization level least >> understood by both the GCC folks and us. Recently (last 5 years?) there has >> been a move to try to make this "optimize without messing up debug info", >> but this is a new movement. > > Another thing that is making -O1 better defined is asan. It is the > optimization level that makes asan fast but still provides useful > backtraces :-) Ok, makes sense. Those uses can use an explicit -O1 though :-) > >> 2) Users who specify -O generally don't know it maps onto -O1. They almost >> certainly don't want whatever -O1 provides. In my experience, most are >> coming from Sun, HP or other compilers, where -O was a generally useful flag. >> >> 3) There are some benchmarks that pass -O (because of #2), which is >> ridiculous, but reflects some reality that people use -O. I don't recall >> what these benchmarks were. >> >> These are reasons that I suggested the change. I really don't like -O1 :-) > > I haven't seen -O being used in wild, so I OK with keeping it mapping to -O2. I'd be curious to know how many files in a linux distro are built with -O. I wouldn't be surprised if it is 5-10%. -Chris _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
