On Mon, 2005-02-28 at 12:51, Vladimir Ivanov wrote: > Hello all, > > While compiling this: > http://sourceforge.net/projects/raytracer/ > > I think I've spotted a bug in ARM port of G++. > > The problem is that many method functions tend to save all callee-saved FP > registers, while they use few or none of them. > > Here's a small snippet from "base3d.cpp" file: > > 00000528 <_ZN6Base3d8rotateV1Ed>: > 528: e1a0c00d mov ip, sp > 52c: e92ddff0 stmdb sp!, {r4, r5, r6, r7, r8, r9, sl, > fp, ip, lr, pc} > 530: ed2d420c sfm f4, 4, [sp, #-48]! > 534: e24cb004 sub fp, ip, #4 ; 0x4 > 538: e24dd0cc sub sp, sp, #204 ; 0xcc > 53c: e59f3288 ldr r3, [pc, #648] ; 7cc <.text+0x7cc> > ... > > Function uses only F0 register, although F4-F7 are saved/restored. This > leads to great speed penalty, especially when coprocessors like Crunch > have many registers. > > PowerPC port shows no such problem, so I think it's something in ARM port. > > Sorry I cannot provide small enough example, C++ is not my area of > expertise.
[I tried to reply to this yesterday, but the response has failed to show up here. I suspect it was mailer problems at my end, but if you get this twice I apologise.] I think this is most likely a consequence of SJLJ exceptions. It should be fixed when we move to the EABI unwinding tables. R.
