------- Comment #20 from ubizjak at gmail dot com 2007-04-05 19:39 ------- (In reply to comment #19) > what are you using for a compiler? Im using a mainline from mid march, and
gcc version 4.3.0 20070404 (experimental) on i686-pc-linux-gnu with > it, my .optimized files diff exactly the same, and I get the aforementioned > time differences in the executables. This is because -march=pentium4 enables all sse builtins for both cases. > (sse.c and sse-bad.c are same, just different names to get different output > files) > > 2007-03-13/gcc> diff sse.c sse-bad.c > > 2007-03-13/gcc>./xgcc -B./ sse.c -fdump-tree-optimized -O3 -march=pentium4 -o > sse > > 2007-03-13/gcc>./xgcc -B./ sse-bad.c -fdump-tree-optimized -O3 -march=pentium4 > -mfpmath=sse -o sse-bad This is known effect of SFmode SSE being slower than SFmode x87. But again, you have enabled sse(2) builtins due to -march=pentium4. Please try to compile using only "-O2" and "-O2 -msse". x87 math will be used in both cases, but .optimized will show the difference. You can also try to compile with and without -ffast-math. IMO it is not acceptabe for tree dumps to depend on target compile flag in any way... -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19780
