On Sat, Apr 2, 2011 at 12:04 PM, Xerxes Ranby <xerxes@xxxxxxxxx> wrote: > On 2011-04-02 00:20, Michael Hope wrote: >> >> On Sat, Apr 2, 2011 at 1:50 AM,<omalleys@xxxxxxx> wrote: >>> >>> Did anyone ever get llvm/clang working? >>> >>> It -says- it is fast, good optimization, faster binaries, aimed at >>> generating better errors, and has good tools for debugging. :) the >>> darwin-arm (and x86 ports are production quality. >>> There isn't support for EABI or< armv6 in the ARM-backend yet. >> >> I'm having a bit of a look at this for Linaro at the moment. LLVM is >> quite respectable, and generates code that is slower than GCC but >> generally in the same ballpark. Of the three benchmarks I've tried, >> two took 8 % longer to run on an A9 and pybench took more like 40 % >> longer to run. pybench is sensitive to having a good inner loop >> though. >> >> -- Michael >> _______________________________________________ >> arm mailing list >> arm@xxxxxxxxxxxxxxxxxxxxxxx >> https://admin.fedoraproject.org/mailman/listinfo/arm > > Hi Michael! > > For what I know, LLVM defaults to ARMv4t code generation unless it gets told > that it are allowed to use newer code generation. > > This llvm bug tracked how llvm and clang implemented X86 cpu feature > autodetection code to make clang generate the best code available for any > given host when using -march=native. > http://www.llvm.org/bugs/show_bug.cgi?id=5389 > > I have added an initial cpu features auto-detection code for ARM to that > bug-report for the LLVM part. > > Do you get better performance on your A9 tests when running clang with > clang -mcpu=generic -mattr=+neon,-thumb2,+v6,+vfp2 I've only done a first pass, but I'm fairly sure I used clang -mcpu=cortex-a9 -mfpu=neon. I don't think clang supports ARMv4T at all. I'm working on automating the benchmarks at the moment and I'll add llvm into that. Better than some throw-away, unreproducable results :) -- Michael _______________________________________________ arm mailing list arm@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/arm
