Quoting Michael Hope <michael.hope@xxxxxxxxxx>: > 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 :) > According to what I understood from their web docs (which may or may not be accurate..) and was listed under "known issues" I think for the "backend" for the 2.8 release: -armv4 doesn't have thumb support yet. -EABI is unsupported for all processors. I was unclear whether that was just the llvm/clang toolchain or it also included the llvm-gccX toolchain. LLVM 2.9 is scheduled to be released today (April 4th). 2.8 is still listed as the current version on their website, so there might be a delay or it may not be updated yet. _______________________________________________ arm mailing list arm@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/arm
