On Thu, 2018-09-06 at 09:55 -0700, Erik Joelsson wrote: > On 2018-09-06 03:12, Severin Gehwolf wrote: > > Hi David, > > > > On Thu, 2018-09-06 at 07:32 +1000, David Holmes wrote: > > > Hi Severin, > > > > > > Might as well raise this here too as it's really a build philosophy > > > issue. Shouldn't flags like -ffp-contract=off (and the existing AIX > > > -qfloat=nomaf) be toolchain specific rather than platform specific? > > > > Looks like Clang has -ffp-contract: > > https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-ffp-contract > > > > Is there any other (supported) toolchain other than gcc and clang on > > linux? As for AIX I suppose there is only on supported toolchain? > > We don't have a big variety of toolchain/platform combinations that we > actively support no, but we still try to be conscious of when a flag is > toolchain specific and when it's platform specific. There is certainly > interest in using other compilers on Linux, and GCC could potentially be > used on other platforms as well. Until we actually try it, it can be > hard to know for sure if a flag actually applies in other cases for the > toolchain and/or platform, but we can at least try our best guess.
Thanks, Erik. GCC supports -ffp-contract since 4.6. Clang has -ffp- contract too. Question is beginning from which version. That's why I'd expect for those flags to work on linux. Is there anything else I need to check? Would it be preferred if I moved this into a block like this? ifeq ($(TOOLCHAIN_TYPE), gcc) [...] endif Thanks, Severin > /Erik > > Thanks, > > Severin > > > > > Thanks, > > > David > > > > > > On 5/09/2018 11:12 PM, Severin Gehwolf wrote: > > > > Hi, > > > > > > > > Cross-posting this review-thread on core-libs-dev and build-dev as > > > > this > > > > is a build change, but affects fdlibm which is core-libs. > > > > > > > > With JDK-8170153 optimization for fdlibm code has been turned on > > > > for > > > > ppc64 s390 and aarch64. This patch intends to turn it on on all > > > > arches > > > > on Linux. I've not observed any precision issues. Is there a good > > > > reason to not use -O3 -ffp-contract=off everywhere? > > > > > > > > Bug: https://bugs.openjdk.java.net/browse/JDK-8210416 > > > > webrev: > > > > http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210416/webrev.01/ > > > > > > > > Testing: - java/lang/Math, java/lang/StrictMath tests (all pass). > > > > - Currently running through submit repo. > > > > > > > > A simple micro benchmark from JDK-8170153[1] shows these numbers > > > > for > > > > StrictMath: > > > > > > > > Function | before | after > > > > ---------------------------------------------- > > > > sin | 0m33.382s | 0m18.731s > > > > cos | 0m31.562s | 0m18.796s > > > > tan | 0m33.657s | 0m21.093s > > > > atan | 0m5.714s | 0m4.902s > > > > log | 0m6.212s | 0m4.439s > > > > log10 | 0m7.946s | 0m5.543s > > > > sqrt | 0m0.481s | 0m0.449s > > > > cbrt | 0m5.295s | 0m5.214s > > > > tanh | 0m1.404s | 0m1.307s > > > > log1p | 0m6.457s | 0m5.131s > > > > IEEEremainder | 0m10.629s | 0m6.048s > > > > atan2 | 0m8.037s | 0m5.668s > > > > hypot | 0m2.171s | 0m2.147s > > > > > > > > Thoughts? > > > > > > > > Thanks, > > > > Severin > > > > > > > > > >
