Hi Ramana, >> I used --target=arm-none-linux-gnueabihf --host=arm-none-linux-gnueabihf >> --build=arm-none-linux-gnueabihf --with-float=hard. However it seems that the >> default armhf settings are incorrect. I shouldn't need the --with-float=hard >> since >> that is obviously implied by armhf, and they should also imply armv7-a with >> vfpv3 >> according to documentation. It seems to get confused and skip some tests. I >> tried >> using --with-fpu=auto, but that doesn't work at all, so in the end I forced >> it like: >> --with-arch=armv8-a --with-fpu=neon-fp-armv8. With this it runs a few more >> tests. > > Yeah that's a wart that I don't like. > > armhf just implies the hard float ABI and came into being to help > distinguish from the Base PCS for some of the distros at the time > (2010s). However we didn't want to set a baseline arch at that time > given the imminent arrival of v8-a and thus the specification of > --with-arch , --with-fpu and --with-float became second nature to many > of us working on it at that time.
Looking at it, the default is indeed incorrect, you get: '-mcpu=arm10e' '-mfloat-abi=hard' '-marm' '-march=armv5te+fp' That's like 25 years out of date! However all the armhf distros have Armv7-a as the baseline and use Thumb-2: '-mfloat-abi=hard' '-mthumb' '-march=armv7-a+fp' So the issue is that dg-require-effective-target arm_arch_v7a_ok doesn't work on armhf. It seems that if you specify an architecture even with hard-float configured, it turns off FP and then complains because hard-float implies you must have FP... So in most configurations Iincluding the one used by distro compilers) we basically skip lots of tests for no apparent reason... > Ok, thanks for promising to do so - I trust you to get it done. Please > try out various combinations of -march v7ve, v7-a , v8-a with the tool > as each of them have slightly different rules. For instance v7ve > allows LDREXD and STREXD to be single copy atomic for 64 bit loads > whereas v7-a did not . You mean LDRD may be generated on CPUs with LPAE. We use LDREXD by default since that is always atomic on v7-a. > Ok if no regressions but as you might get nagged by the post commit CI ... Thanks, I've committed it. Those links don't show anything concrete, however I do note the CI didn't pick up v2. Btw you're happy with backports if there are no issues reported for a few days? Cheers, Wilco _______________________________________________ linaro-toolchain mailing list -- linaro-toolchain@lists.linaro.org To unsubscribe send an email to linaro-toolchain-le...@lists.linaro.org
