> Tim Prince writes: > > kanishk rastogi wrote: > > > hi all, > > > I wanted to know if when i specify -O[0-3] flag to gcc does gcc > > > optimize the code even violating ABI for that specific arch. > > > If yes can i specify gcc not to violate the ABI .... > > > I am mostly concerned witht he ABI specification which tells how to > > > call another function.. > > > > > > > Only the -Os changes the value of -mpreferred-stack-boundary, breaking > > the ability to support vectorization or other alignment dependent code > > in the callee. > > -Os breaks vectorization? That would be A Bug, for sure. Do you have > references, Bugzilla entries, for this? > I don't think -mpreferred-stack-boundary breaks vectorization, but it can affect vectorization because vectorization is sensitive to alignment, and the ability to force the alignment of arrays on the stack currently depends on the preferred stack boundary. You can see http://gcc.gnu.org/ml/gcc-patches/2007-10/msg00202.html for more details. dorit > Andrew.
