Messages in this thread | | | Date | Sat, 11 Apr 2015 16:41:35 +0200 | From | Markus Trippelsdorf <> | Subject | Re: [PATCH] x86: Align jump targets to 1 byte boundaries |
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On 2015.04.10 at 06:18 -0700, H. Peter Anvin wrote: > On 04/10/2015 05:50 AM, Denys Vlasenko wrote: > > > > However, I'm an -Os guy. Expect -O2 people to disagree :) > > > > The problem with -Os is that the compiler will make *any* tradeoffs to > save a byte. It is really designed to squeeze as much code into a > fixed-size chunk, e.g. a ROM, as possible. > > We have asked for an -Okernel mode from the gcc folks forever. It > basically would mean "-Os except when really dumb."
If you want the best of both worlds perhaps you should reconsider Andy's LTO patch? With -flto gcc automatically optimizes all functions that it considers cold for size. So you could expect some code size savings even with -O2 (or -O3).
-- Markus
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