8210425: [x86] sharedRuntimeTrig/sharedRuntimeTrans compiled without optimization

Severin Gehwolf sgehwolf at redhat.com
Wed Sep 12 12:44:48 UTC 2018


Updated webrev since fdlibm build change seems to have settled:

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?


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-bounces at openjdk.java.net on behalf of aph at 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

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