> I found another bug in current implementation. A patch for it doesn't > cure i686-linux- bootstrap, but fixes fails on some tests (see > attached). > > The problem was that we tried to add runtime tests for alignment even > if both SRC and DST had unknown alignment - in this case it could be > impossible to make them both aligned simultaneously, so I think it's > easier to even not try to use aligned SSE-moves at all. Generation of > prologues with runtime tests could be used only if at least one > alignment is known - otherwise it's incorrect. Probably, generation of > such prologues could be removed from MEMMOV at all for now.
The prologues always align the destination as it helps more than aligning source on most chips. I do not see problem with that. But for SSE either we should arrange unaligned load opcodes (that is what I see in generated code, but I guess it depends on -march setting) or simply disqualify the sse_loop algorithm in decide_alg when alignment is not know. > > Though, even with this fix i686-bootstrap still fails. Configure for > the bootstrap-fail reproducing: > CC="gcc -m32" CXX="g++ -m32" ../configure --with-arch=core2 > --with-cpu=atom --prefix=`pwd` i686-linux --with-fpmath=sse > --enable-languages=c,c++,fortran Default i686-linux bootstrap was working for me. I will try your setting but my time today evening and at weekend is limited. Honza