RFR: JDK-8316991: Reduce nullable allocation merges [v2]

[Tobias Hartmann]

On Mon, 9 Oct 2023 21:47:45 GMT, Cesar Soares Lucas <cslucas at openjdk.org> wrote:

>> I didn't look at this in detail yet but submitted testing. I see the following failures.
>> 
>> `compiler/eliminateAutobox/TestByteBoxing.java` with `-ea -esa -XX:CompileThreshold=100 -XX:+UnlockExperimentalVMOptions -server -XX:-TieredCompilation`:
>> 
>> 
>> # A fatal error has been detected by the Java Runtime Environment:
>> #
>> #  Internal Error (/workspace/open/src/hotspot/share/opto/loopnode.cpp:2178), pid=951972, tid=951999
>> #  assert(inner->is_valid_counted_loop(T_INT) && inner->is_strip_mined()) failed: OuterStripMinedLoop should have been removed
>> #
>> # JRE version: Java(TM) SE Runtime Environment (22.0) (fastdebug build 22-internal-2023-10-03-0709344.tobias.hartmann.jdk2)
>> # Java VM: Java HotSpot(TM) 64-Bit Server VM (fastdebug 22-internal-2023-10-03-0709344.tobias.hartmann.jdk2, mixed mode, sharing, compressed oops, compressed class ptrs, g1 gc, linux-amd64)
>> # Problematic frame:
>> # V  [libjvm.so+0x128082c]  LoopNode::verify_strip_mined(int) const+0xcc
>> 
>> Current CompileTask:
>> C2:   1438  263 %  b        compiler.eliminateAutobox.TestByteBoxing::main @ 1358 (1805 bytes)
>> 
>> Stack: [0x00007f0efc9cb000,0x00007f0efcacb000],  sp=0x00007f0efcac57a0,  free space=1001k
>> Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
>> V  [libjvm.so+0x128082c]  LoopNode::verify_strip_mined(int) const+0xcc  (loopnode.cpp:2178)
>> V  [libjvm.so+0x1256ead]  PathFrequency::to(Node*)+0x70d  (loopPredicate.cpp:988)
>> V  [libjvm.so+0x1258b49]  PhaseIdealLoop::loop_predication_impl(IdealLoopTree*)+0x8e9  (loopPredicate.cpp:1462)
>> V  [libjvm.so+0x125989a]  IdealLoopTree::loop_predication(PhaseIdealLoop*)+0x9a  (loopPredicate.cpp:1536)
>> V  [libjvm.so+0x12a28d7]  PhaseIdealLoop::build_and_optimize()+0xf57  (loopnode.cpp:4582)
>> V  [libjvm.so+0x9ee7fb]  PhaseIdealLoop::optimize(PhaseIterGVN&, LoopOptsMode)+0x3ab  (loopnode.hpp:1114)
>> V  [libjvm.so+0x9e9db6]  Compile::Optimize()+0xdf6  (compile.cpp:2362)
>> 
>> 
>> `compiler/eliminateAutobox/TestByteBoxing.java` with  `-XX:+UnlockDiagnosticVMOptions -XX:-TieredCompilation -XX:+StressArrayCopyMacroNode -XX:+StressLCM -XX:+StressGCM -XX:+StressIGVN -XX:+StressCCP -XX:+StressMethodHandleLinkerInlining -XX:+StressCompiledExceptionHandlers`:
>> 
>> 
>> # A fatal error has been detected by the Java Runtime Environment:
>> #
>> #  Internal Error (workspace/open/src/hotspot/share/opto/loopnode.cpp:6035), pid=1353611, tid=1353627
>> #  Error: ShouldNotReachHere()
>> #
>> # JRE version: Java(TM) SE Runtime Envi...
>
> Hello @TobiHartmann, I pushed a fix for the test failures that you reported. Could you please re-run your tests? Thank you.

Hi @JohnTortugo, sure. I re-submitted testing and will report back once it finished.

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PR Comment: https://git.openjdk.org/jdk/pull/15825#issuecomment-1758916712