Hi Severin,
On 7/09/2018 6:01 PM, Severin Gehwolf wrote:
Hi,
On Thu, 2018-09-06 at 10:55 -0700, Erik Joelsson wrote:
On 2018-09-06 10:29, Severin Gehwolf wrote:
On Thu, 2018-09-06 at 09:55 -0700, Erik Joelsson wrote:
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
Yes, making it conditional on toolchain type is what David was after.
Right. David, given that -ffp-contract is available for clang too, do
you still want me to add this into a toolchain specific block?
Personally I'd prefer it but I will defer to Erik and Magnus on this.
Thanks,
David
Also note that solaris doesn't seem to be handling this code any
special, so there would be a difference between gcc + solaris and
solstudio + solaris. Rather hypothetical case, I suppose, but still ;-)
One of the arguments were that gcc is being used on other platforms
than linux.
You can also consider adding a capability check if you know that
versions of the compiler that should still work don't have the feature.
One clarification: Does a capability check mean doing this at the
configure step or is there a way one has access to toolchain versions
in make files?
Thanks,
Severin
/Erik
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
