On Mon, Oct 26, 2020 at 7:23 AM Jan Hubicka <hubi...@ucw.cz> wrote: > > Hi, > this patch implements thre two-state optimize_for_size predicates, so with -Os > and with profile feedback for never executed code it returns OPTIMIZE_SIZE_MAX > while in cases we decide to optimize for size based on branch prediction logic > it return OPTIMIZE_SIZE_BALLANCED. > > The idea is that for places where we guess that code is unlikely we do not > want to do extreme optimizations for size that leads to many fold slowdowns > (using idiv rather than few shigts or using rep based inlined stringops). > > I will update RTL handling code to also support this with BB granuality (which > we don't currently). We also should make attribute cold to lead to > OPTIMIZE_SIZE_MAX I would say. > > LLVM has -Os and -Oz levels where -Oz is our -Os and LLVM's -Os would > ocrrespond to OPTIMIZE_SIZE_BALLANCED. I wonder if we want to export > this to command line somehow? For me it would be definitly useful to > test things, I am not sure how "weaker" -Os is desired in practice. > > Bootstrapped/regtested x86_64-linux, I will commit it later today if > there are no comments. > > H.J., can you plase update your patch on stringopts? >
Please ahead. My patches should be orthogonal to yours. -- H.J.
