Hi, can I please have a review and approval for pushing the following small, ppc64-only fix to jdk8u-dev:
http://cr.openjdk.java.net/~simonis/webrevs/2016/8172053/ https://bugs.openjdk.java.net/browse/JDK-8172053 The problem is that the recent downport of "8170153: PPC64/s390x/aarch64: Poor StrictMath performance due to non-optimized compilation" breaks the build of jdk8u with the original gcc 4.3 on linux/ppc64. We should however ensure, that an update-release will not break the original tool chain used for a released version of Java. Notice, that this change won't go to jdk9 because it only fixes an issue caused by the downport of another fix to jdk8u which doesn't exist in jdk9. JDK-8170153 increased the optimization level for the compilation of fdlibm on both linux/ppc64 and linux/ppc64le. This only worked by using the option '-ffp-contract=off' which guaranteed correct IEEE floating point behavior. Unfortunately, '-ffp-contract' is only available since gcc 4.6. For ppc64le that's no problem since ppc64le support only appeared in gcc 4.8.3. But on ppc64 (big endian) we traditionally compiled with gcc 4.3 which only knows '-mno-fused-madd'. However, that's still not enough to get the float computations right - we additionally have to supply '-fno-strict-aliasing'. I've tested the new configuration (i.e. '-mno-fused-madd -fno-strict-aliasing') with the corresponding jtreg and JCK tests and couldn't find any issue. Thank you and best regards, Volker
