buggy behavior in AMD64NodeLIRBuilder.emitCompareBranchMemory

Wed May 14 18:01:38 UTC 2014

Thanks for the test case.  I’ve been narrowing it down in between a few other things but I was seeing an issue with a mirrored unsigned compare.  It generates bad code in the compiler itself and then fails much later.  It’s possible there are multiple things going on.  Anyway, I hope to have it resolved today.

tom

On May 14, 2014, at 10:56 AM, Yudi Zheng <yudi.zheng at usi.ch> wrote:

> In case you might need it, please find attached the simplified test case.
> During the TailDuplicationPhase when compiling TailDuplicatoinTest.bar,
> some ObjectEqualsNode is evaluated to false..
> (com.oracle.graal.nodes.calc.ObjectEqualsNode.java#64)
> 
> - Yudi
> 
> 
> On 13 May 2014, at 00:40, Tom Rodriguez <tom.rodriguez at oracle.com<mailto:tom.rodriguez at oracle.com>> wrote:
> 
> Thanks for the report.  I’m looking into it.
> 
> tom
> 
> On May 12, 2014, at 1:10 PM, Yudi Zheng <yudi.zheng at usi.ch<mailto:yudi.zheng at usi.ch>> wrote:
> 
> Hi,
> 
> 1. A minor problem is that the default TypeProfileWidth is 2, resulting in lots of megamorphic-inlining with a probability of 60~70% in many cases,
> instead of polymorphic-inlining.
> 
> 2. When running with -XX:TypeProfileWidth=8, I observed buggy behavior:
> 
> mx vm -XX:+BootstrapGraal -XX:TypeProfileWidth=8 -version
> Bootstrapping Graal.......................com.oracle.graal.compiler.common.GraalInternalError: should not reach here
> at lir instruction: B192 at 1350 LCMP (address: [rax|j + 24], y: long[33286881400|0x7c00d8078]{HotSpotType<Lcom/oracle/graal/nodes/DeoptimizingNode$DeoptBefore;, resolved>}) kind: long
> [B0, B2, B3, B5, B6, B8, B416, B419, B9, B11, B12, B14, B16, B17, B19, B21, B413, B23, B25, B26, B28, B29, B31, B409, B412, B32, B33, B35, B36, B38, B39, B41, B42, B44, B45, B47, B49, B50, B52, B54, B53, B55, B56, B57, B59, B61, B63, B65, B66, B67, B69, B70, B72, B74, B77, B79, B80, B94, B96, B98, B99, B101, B102, B103, B104, B107, B108, B109, B110, B113, B114, B115, B117, B118, B120, B122, B125, B127, B128, B129, B143, B145, B147, B148, B160, B126, B119, B149, B116, B130, B132, B153, B133, B136, B138, B139, B141, B142, B137, B140, B150, B134, B168, B105, B166, B171, B180, B181, B183, B186, B188, B190, B192, B194, B196, B198, B200, B197, B161, B170, B179, B177, B178, B184, B403, B78, B193, B202, B203, B204, B209, B211, B212, B214, B399, B401, B215, B216, B218, B220, B222, B397, B71, B208, B205, B206, B100, B195, B201, B187, B189, B68, B191, B199, B219, B224, B226, B228, B229, B231, B233, B394, B395, B221, B223, B82, B84, B173, B174, B154, B155, B51, B48, B232, B235, B239, B393, B236, B238, B234, B85, B87, B89, B90, B92, B93, B88, B240, B242, B284, B286, B288, B289, B291, B294, B296, B297, B299, B300, B302, B304, B307, B308, B310, B311, B313, B315, B317, B318, B320, B322, B323, B325, B326, B327, B343, B345, B346, B348, B349, B351, B354, B356, B357, B358, B360, B362, B364, B365, B367, B369, B372, B368, B373, B83, B371, B46, B352, B237, B287, B316, B330, B332, B333, B335, B336, B337, B244, B246, B247, B249, B250, B252, B254, B257, B258, B260, B261, B263, B265, B267, B268, B270, B273, B275, B276, B370, B266, B207, B285, B314, B264, B91, B355, B295, B245, B339, B384, B301, B306, B251, B256, B390, B391, B281, B283, B167, B282, B347, B382, B344, B30, B27, B378, B379, B175, B385, B388, B324, B386, B34, B407, B259, B280, B402, B312, B387, B309, B62, B389, B24, B410, B210, B392, B165, B230, B278, B159, B415, B396, B135, B404, B262, B169, B157, B10, B381, B15, B331, B376, B277, B405, B414, B37, B1, B213, B398, B417, B279, B418, B408, B400, B176, B338, B58, B40, B151, B274, B411, B380, B375, B334, B7, B340, B64, B4, B377, B406, B60, B13, B172, B163, B106, B86, B217, B18, B112, B383]
> at com.oracle.graal.compiler.common.GraalInternalError.shouldNotReachHere(GraalInternalError.java:44)
> at com.oracle.graal.lir.amd64.AMD64Compare$CompareMemoryOp.emitMemAccess(AMD64Compare.java:129)
> at com.oracle.graal.lir.amd64.AMD64Move$MemOp.emitCode(AMD64Move.java:129)
> at com.oracle.graal.lir.amd64.AMD64LIRInstruction.emitCode(AMD64LIRInstruction.java:36)
> at com.oracle.graal.lir.asm.CompilationResultBuilder.emitOp(CompilationResultBuilder.java:350)
> at com.oracle.graal.lir.asm.CompilationResultBuilder.emitBlock(CompilationResultBuilder.java:341)
> at com.oracle.graal.lir.asm.CompilationResultBuilder.emit(CompilationResultBuilder.java:323)
> at com.oracle.graal.hotspot.amd64.AMD64HotSpotBackend.emitCodeBody(AMD64HotSpotBackend.java:301)
> at com.oracle.graal.hotspot.amd64.AMD64HotSpotBackend.emitCode(AMD64HotSpotBackend.java:254)
> at com.oracle.graal.compiler.GraalCompiler.emitCode(GraalCompiler.java:288)
> at com.oracle.graal.compiler.GraalCompiler.emitBackEnd(GraalCompiler.java:200)
> at com.oracle.graal.compiler.GraalCompiler.compileGraph(GraalCompiler.java:141)
> at com.oracle.graal.hotspot.CompilationTask.runCompilation(CompilationTask.java:302)
> at com.oracle.graal.hotspot.CompilationTask.run(CompilationTask.java:159)
> at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
> at java.lang.Thread.run(Thread.java:745)
> at com.oracle.graal.compiler.CompilerThread.run(CompilerThread.java:48)
> 
> 
> The potential bug can be tracked in com.oracle.graal.compiler.amd64.AMD64NodeLIRBuilder.emitCompareBranchMemory
> (-G:Dump= -G:MethodFilter=com.oracle.graal.compiler.amd64.AMD64NodeLIRBuilder.emitCompareBranchMemory),
> and can be bypassed either by not inlining com.oracle.graal.compiler.amd64.AMD64NodeLIRBuilder.getMemoryKind,
> or by skipping the TailDuplicationPhase.
> 
> I guess that the TailDuplicationPhase dropped some of the IfNode. Could be verified using the following code:
> 
>  protected ComplexMatchResult emitCompareBranchMemory(IfNode ifNode, CompareNode compare, ValueNode value, Access access) {
>      Condition cond = compare.condition();
>      Kind kind = getMemoryKind(access);
> 
>      if (kind != Kind.Long) {
>          notInlinedMethodPlaceHolder(kind);
>      }
> 
> After tail duplication at some merge node, the IfNode<if (kind != Kind.Long)> disappeared..
> 
> - Yudi
> 
> 
> 
> 
> <TailDuplicationTest.java>