http://cr.openjdk.java.net/~vlivanov/8074548/webrev.00/ https://bugs.openjdk.java.net/browse/JDK-8074548
MethodHandleImpl::profileBoolean doesn't update never-taken branch count when hitting a deopt on it. As a result, for rarely taken branches consequent compilations consider them as never-taken and prune them again causing repeated deopts. It severely affects peak performance.
The fix is to update MHI::profileBoolean intrinsic to insert a guard and uncommon trap w/ reexecute bit set for never-seen value. Once previously never seen value is encountered, the execution resumes after deopt in MHI::profileBoolean and corresponding count becomes non-zero.
The guard doesn't add any additional overhead, since it dominates all value usages and all branches on the same value are eliminated.
Testing: java/lang/invoke, nashorn, octane Best regards, Vladimir Ivanov _______________________________________________ mlvm-dev mailing list mlvm-dev@openjdk.java.net http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
