On Fri, Mar 7, 2008 at 12:46 PM, Jakub Jelinek <[EMAIL PROTECTED]> wrote: > On Fri, Mar 07, 2008 at 11:10:53AM +0100, Richard Guenther wrote: > > On Fri, Mar 7, 2008 at 11:02 AM, Philipp Marek <[EMAIL PROTECTED]> wrote: > > > > I wrote some perl scripts to test this. I took a "alldefconfig" i686 > > > kernel, let objdump disassemble it, and on "iret", "ret", "ljmp" or > "jmp" > > > with a 4 byte address I store the last few bytes. Another script goes > > > through these block-ends, and estimates the number of bytes saved, if > > > identical sequences get changed into a 5 byte opcode (jump with 32bit > > > address). > > > > > Sounds like what -frtl-abstract-sequences is trying to do. > > Not exactly. AFAIK -frtl-abstract-sequences works at a function level, only > same sequences within one function are abstracted.
Right - "trying to do" - you'd need to move this to whole-program level with LTO (preferably on the tree level), but the basic idea of outlining same sequences is the same. Richard.
