On Fri, 2018-09-07 at 10:19 -0700, Erik Joelsson wrote: > On 2018-09-07 09:56, Severin Gehwolf wrote: > > On Fri, 2018-09-07 at 09:12 -0700, Erik Joelsson wrote: > > > To me it sounds like we want this flag if the toolchain is either gcc or > > > clang, so please make it conditional on that. > > > > Updated webrev: > > http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210416/webrev.02/ > > > > It now only sets FDLIBM_CFLAGS if gcc supports it and builds fdlibm > > without opt if not. Otherwise it uses -O3 and -ffp-contract=off. If the > > toolchain is clang and on linux it always uses -O3 and -ffp- > > contract=off. The reason, I've done this in configure is a potential > > follow-up fix for hotspot via JDK-8210425 where the CFLAGS could get > > re-used. Thoughts? > > Instead of checking for compiler version, you could simply use the > FLAGS_COMPILER_CHECK_ARGUMENTS macro. This would apply to both gcc and > clang. We usually prefer this over version checks (unless a version is > just known to be unstable with a certain flag, in which case a > capability check will not work). > > CoreLibrarkes.gmk: > 43: I think "with" is superfluous > > Otherwise I think this looks like the right direction.
Latest webrev with Andrew Haley's suggestion to use -O2. I'm observing similar performance numbers than -O3. I haven't changed to the FLAGS_COMPILER_CHECK_ARGUMENTS macro as I'm not clear this is safe to do at this point without breaking cross-compilation: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210416/webrev.03/ Thanks, Severin
