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  1. JDK
  2. JDK-8261914

IfNode::fold_compares_helper faces non-canonicalized bool when running JRuby JSON workload

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    • Subcomponent:
    • Introduced In Build:
      b64
    • Introduced In Version:
      9
    • Resolved In Build:
      b12
    • Verification:
      Not verified

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        Description

        As reported here:
          https://mail.openjdk.java.net/pipermail/hotspot-compiler-dev/2021-February/044182.html

        The issue seems to be time-sensitive. I was able to reproduce this in "release" mode after promoting one of the asserts to guarantee:

        diff --git a/src/hotspot/share/opto/ifnode.cpp b/src/hotspot/share/opto/ifnode.cpp
        index 29624765324..467d8f19276 100644
        --- a/src/hotspot/share/opto/ifnode.cpp
        +++ b/src/hotspot/share/opto/ifnode.cpp
        @@ -948,7 +948,9 @@ bool IfNode::fold_compares_helper(ProjNode* proj, ProjNode* success, ProjNode* f
              assert((dom_bool->_test.is_less() && proj->_con) ||
                     (dom_bool->_test.is_greater() && !proj->_con), "incorrect test");
              // this test was canonicalized
        - assert(this_bool->_test.is_less() && !fail->_con, "incorrect test");
        + guarantee(this_bool->_test.is_less() && !fail->_con, "incorrect test: dom_bool.test=%d
        proj._con=%d this_bool.test=%d fail._con=%d",
        + dom_bool->_test._test, proj->_con,
        + this_bool->_test._test, fail->_con);

              cond = (hi_test == BoolTest::le || hi_test == BoolTest::gt) ? BoolTest::gt : BoolTest::ge;

        ...which then fails with:

        # A fatal error has been detected by the Java Runtime Environment:
        #
        # Internal Error (ifnode.cpp:955), pid=2438111, tid=2438182
        # guarantee(this_bool->_test.is_less() && !fail->_con) failed: incorrect test: dom_bool.test=3
        proj._con=1 this_bool.test=7 fail._con=1
        #
        # JRE version: OpenJDK Runtime Environment (17.0) (build 17-internal+0-adhoc.shade.jdk)
        # Java VM: OpenJDK 64-Bit Server VM (17-internal+0-adhoc.shade.jdk, mixed mode, sharing, tiered,
        compressed oops, compressed class ptrs, g1 gc, linux-amd64)
        # Problematic frame:
        # V [libjvm.so+0x7fc3ee] IfNode::fold_compares_helper(ProjNode*, ProjNode*, ProjNode*,
        PhaseIterGVN*) [clone .part.0]+0x19e
        #
        # Core dump will be written. Default location: Core dumps may be processed with
        "/usr/share/apport/apport %p %s %c %d %P %E" (or dumping to
        /home/shade/temp/jruby/jruby-issue-6554/core.2438111)
        #
        # An error report file with more information is saved as:
        # /home/shade/temp/jruby/jruby-issue-6554/hs_err_pid2438111.log
        #
        # Compiler replay data is saved as:
        # /home/shade/temp/jruby/jruby-issue-6554/replay_pid2438111.log

        "this_bool.test=7" means the test is "GE". The downstream code does not expect this. It expects the test to be canonicalized.

        JDK-8261912 should separately provide the defensive bailout when this happens.

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                Assignee:
                roland Roland Westrelin
                Reporter:
                shade Aleksey Shipilev
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                  Created:
                  Updated:
                  Resolved: