8308660: C2 compilation hits 'node must be dead' assert

[rwestrel]

In IfNode::fold_compares_helper(), adjusted_val is:

(SubI (AddI top constant) 0)

which is then transformed to the top node. The code, next, tries to destroy the adjusted_val node i.e. the top node. That results in the assert failure. Given We're trying to fold 2 ifs in a dying part of the graph, the fix is straightforward: test adjusted_val for top and bail out from the transformation if that's the case.

---

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Issue

• JDK-8308660: C2 compilation hits 'node must be dead' assert (Bug - P3)

Reviewers

• Christian Hagedorn (@chhagedorn - Reviewer)
• Vladimir Kozlov (@vnkozlov - Reviewer)

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@rwestrel This change now passes all automated pre-integration checks.

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8308660: C2 compilation hits 'node must be dead' assert

Reviewed-by: chagedorn, kvn

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At the time when this comment was updated there had been 165 new commits pushed to the master branch:

• 85fc47c81af81a595dc88e61454d8ba2d860f301: 8327180: Failed: java/io/ObjectStreamClass/ObjectStreamClassCaching.java#G1
• 569b05addf69698fc93026b4dca69bc6ca0920b6: 8327818: Implement Kerberos debug with sun.security.util.Debug
• dec68d7e36a9436468594416272c44a2afbece8d: 8328234: Remove unused nativeUtils files
• 7734466c4627c51b2c24b4b4dbf6db4184607aa3: 8325871: Move StringTable and SymbolTable rehashing calls
• 9e98118f289e98ca9f3be2a274e0ddf8822aaa7c: 8328177: Move LDFLAGS_JDK[LIB/EXE] to JdkNativeCompilation.gmk
• f3af91815a662b195938b26962a8670a4a692220: 8327945: Inline HasScavengableOops
• fb390d202c8bbbbb87ba48fd01387feb35a1b768: 8327839: Crash with unboxing and widening primitive conversion in switch
• 86f17447362483162a5983c270e0b530d8d99354: 8328248: Convert javax/swing/JSlider/6587742/bug6587742.java applet test to main
• 7baec6622254fc21e315b974a213605a7605daac: 8328168: Epsilon: Premature OOM when allocating object larger than uncommitted heap size
• c342188fd978dd94e7788fb0fb0345fd8c0eaa9a: 8328074: Add jcheck whitespace checking for assembly files
• ... and 155 more: https://git.openjdk.org/jdk/compare/784f11c35d7f8646c7354c756ac8801a3d685874...master

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• 02: Full - Incremental (43a1d337)
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[rwestrel]

Otherwise, looks good!

Thanks for reviewing this.

[rwestrel]

Thanks for the reviews @chhagedorn @vnkozlov

[rwestrel]

/integrate

[openjdk[bot]]

Going to push as commit 91baac9b9de91b16e602dcf1d9f41e20bec38ffc. Since your change was applied there have been 146 commits pushed to the master branch:

• 71f9c4e7fd5818be6e79dead3caa02d738456ad6: 8320534: fatal error for the NMTBenchmark test run for the mainline build
• bfba4894e14c9547735a6b4ae73ed423af09f0d4: 8328157: Move C[XX]FLAGS_JDK[LIB/EXE] to JdkNativeCompilation.gmk
• 42aec8c5e72837400818d931855bade8acad8e9d: 8328146: Set LIBCXX automatically
• 90ab52e598f74ed872fe404130d57f6596430727: 8328166: Epsilon: 'EpsilonHeap::allocate_work' misuses the parameter 'size' as size in bytes
• bf990c8b32f1ce050450d94f4f8706e5a01aa3ec: 8328269: NonFocusablePopupMenuTest.java should be marked as headful
• 80b98c86b82eb9ffd5aee67a92daa31c8b649cc6: 8320503: Print warning if VM reaches MallocLimit during error reporting
• dde519dc2180742c119ac07221c2a149b9f06c18: 8328066: WhiteBoxResizeTest failure on linux-x86: Could not reserve enough space for 2097152KB object heap
• 80ccc989a892e4d9f4e2c9395a100cfabbdcda64: 8328075: Shenandoah: Avoid forwarding when objects don't move in full-GC
• 5249cc0a79f05b71f4c31bb6b02775976eef77aa: 8328087: Automate javax/swing/JTable/TAB/TAB.java applet test
• c05f8c72239ed3f16ff0d13f4dba795731f9559f: 8316388: Opensource five Swing component related regression tests
• ... and 136 more: https://git.openjdk.org/jdk/compare/784f11c35d7f8646c7354c756ac8801a3d685874...master

Your commit was automatically rebased without conflicts.

[openjdk[bot]]

@rwestrel An unexpected error occurred during integration. No push attempt will be made. The error has been logged and will be investigated. It is possible that this error is caused by a transient issue; feel free to retry the operation.

[rwestrel]

/integrate

[openjdk[bot]]

Going to push as commit 053ff76e14046f796f6e10a9cb2ede1f1ae22ed6. Since your change was applied there have been 176 commits pushed to the master branch:

• e1b0af29e47b46879defce1fc44c30d4d50d0c31: 8323972: C2 compilation fails with assert(!x->as_Loop()->is_loop_nest_inner_loop()) failed: loop was transformed
• c0fc9563a707cb01db4baf3aebede5f6b3ea08d1: 8328275: CodeCache::print_internals should not be called in PRODUCT code
• 4ef591f71f62ee6ea8a603ed7a3e568b348b2c16: 8326964: Remove Eclipse Shared Workspaces
• ac5b6cb2d42bdb8fb1a110ad33411b50cff4ea61: 8327757: Convert javax/swing/JSlider/6524424/bug6524424.java applet to main
• 652fb3aa48fdfe09e827c2a06f76b3a69c711b74: 8328154: Convert sun/java2d/loops/CopyAreaSpeed.java applet test to main
• 9059727df135dc90311bd476124f090b5766092b: 8327182: Move serverAlias into the loop
• 2dd5fba3bd37c577b8442b67a67dbcb22b9a530e: 8319889: Vector API tests trigger VM crashes with -XX:+StressIncrementalInlining
• 3f2e849c54c2a9c55e3b5c9f5a6d3478b83144e3: 8280392: java/awt/Focus/NonFocusableWindowTest/NonfocusableOwnerTest.java failed with "RuntimeException: Test failed."
• c901da48e30d53cb8e4e3c1f0584c5f2d3d095f1: 8327098: GTest needs larger combination limit
• 9e32db266e4c3cc9be273fa6b77112832a43ba4a: 8328309: Remove malformed masked shift instruction selection patterns
• ... and 166 more: https://git.openjdk.org/jdk/compare/784f11c35d7f8646c7354c756ac8801a3d685874...master

Your commit was automatically rebased without conflicts.

[openjdk[bot]]

@rwestrel Pushed as commit 053ff76e14046f796f6e10a9cb2ede1f1ae22ed6.

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