On 2018-09-13 03:02, Severin Gehwolf wrote:
Hi Erik,
On Wed, 2018-09-12 at 10:02 -0700, Erik Joelsson wrote:
Hello Severin,
In configure, we now set FDLIBM_CFLAGS based on toolchain type and
capabilities. In JvmOverrideFiles.gmk, the use of it is still
conditional on Linux. I don't think it should be. We already have the
conditionals we need.
Thanks for the review. Updated webrev:
http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210425/webrev.03/
I wasn't sure whether the precompiled headers handling for gcc/clang is
right and was reluctant to move it out of the linux conditional. The
assumption on my end is that if headers are compiled with -O3, we can't
used them for any other opt level. It should still all work. Thoughts?
Looking at this again, I now realize the whole file has the treatment
for these files repeated for each OS, with slight variations. This
becomes a clash with the change we are now attempting which is toolchain
oriented. I think the easiest way here would be to keep it OS separated
for now by reverting to your previous patch.
You could consider putting the FDLIBM_CFLAGS conditional block outside
the linux block however and apply the "$(FDLIBM_CFLAGS)
$(LIBJVM_FDLIBM_COPY_OPT_FLAG)" flags on the lines in the macosx block
further down as well. The changes for fdlibm as they are now will apply
on macosx since we use clang there, so the jvm change should too.
/Erik
Thanks,
Severin
On 2018-09-12 05:44, Severin Gehwolf wrote:
Hi,
Updated webrev since fdlibm build change seems to have settled:
http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210425/webrev.02/
Optimization is being done at level -O2 (CXX_O_FLAG_NORM) with
-ffp-contract=off when the toolchain (gcc/clang at this point)
supports it. Otherwise no optimization will be done. Those overrides
are no longer in an x86 specific block. Thus, ppc64, aarch64, s390x
will get correct settings too.
How does this look?
Thanks,
Severin
On Wed, 2018-09-12 at 07:16 +0000, Schmidt, Lutz wrote:
I totally agree with Andrew's statement. FP calculations should be
evaluated as the programmer wrote them down. All fiddling around with
sequence or rounding is evil. You lose reproducibility of results.
Regards,
Lutz
On 08.09.18, 11:26, "hotspot-dev on behalf of Andrew Haley"
<hotspot-dev-boun...@openjdk.java.net on behalf of a...@redhat.com> wrote:
On 09/06/2018 03:32 PM, Severin Gehwolf wrote:
> Right. I should note that ppc64, s390x and aarch64 ports don't have
> this optimization turned off as those overrides are in a x86 specific
> block. It appears it hasn't caused issues for these ports so far.
That's just dumb luck. We really should turn off the merging of FP
operations on all platforms.
--
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
