search for: 11410552

...to reproduce this? I tried gcc.c from http://people.csail.mit.edu/smcc/projects/single-file-programs/ and the difference is a bit more noticeable: -O0 -mno-relax-all real 0m13.182s user 0m12.690s sys 0m0.450s -O0 gcc.o is 10932968 bytes. real 0m12.969s user 0m12.520s sys 0m0.410s gcc.o is 11410552 bytes IMHO it would still be reasonable to switch to no-relax-all, but I am probably not the best one to make the call. Cheers, Rafael

...ngle-file-programs/ and the > difference is a bit more noticeable: > > -O0 -mno-relax-all > > real 0m13.182s > user 0m12.690s > sys 0m0.450s > > -O0 > > gcc.o is 10932968 bytes. > > real 0m12.969s > user 0m12.520s > sys 0m0.410s > > gcc.o is 11410552 bytes > > IMHO it would still be reasonable to switch to no-relax-all, but I am > probably not the best one to make the call. That looks like a 1.5% speedup in realtime and 10% speedup in system time (though I'm not sure I believe that). I think it should stay on for -O0 for C file...

> E.g. -mrelax-all is either harmful or not improving enough to give a > measurable improvement. > > Can someone else try to reproduce this? I can. I tried these builds on tmpfs so as to give -mno-relax-all an smaller advantaged for less IO: --enable-optimized --with-optimize-option=-O0 real 3m38.568s user 24m15.097s sys 1m33.550s clang is 69661804 bytes --enable-optimized

Hi all, clang -O0 currently differs from -O1 and higher in passing down -mrelax-all. When compiling assembler files, this results in conditional jumps using the relaxed forms, which is surprising. Based on the discussion on IRC, I did a llvm/clang release build with -O0 for OPTIMIZER and -O0 -mno-relax-all. Result is: -O0 (-mrelax-all) 68m27.893s 254m19.920s 1m45.720s -O0 -mno-relax-all