RFR: 6232281: -XX:-UseLoopSafepoints causes assert(v_false, "Parse::remove_useless_nodes missed this node")

[Tobias Hartmann]

On Thu, 19 Nov 2020 09:05:06 GMT, Roberto Castañeda Lozano <rcastanedalo at openjdk.org> wrote:

> Check for nodes missed by `remove_useless_nodes()` only if PhaseRemoveUseless has actually been run. This makes it possible to use `-XX:-UseLoopSafepoints` without crashing trivially, although implicit assumptions in other parts of C2 about the existence of loop safepoints might lead to more subtle failures for more complex methods.

Looks good to me.

test/hotspot/jtreg/compiler/arguments/TestDisableUseLoopSafepoints.java line 32:

> 30:  *          that other parts of C2 assume that this option is enabled and might
> 31:  *          fail in more subtle ways otherwise.
> 32:  * @run main/othervm -Xcomp -Xbatch -XX:-TieredCompilation

`-Xcomp` implies `-Xbatch`

test/hotspot/jtreg/compiler/arguments/TestDisableUseLoopSafepoints.java line 31:

> 29:  *          missed this node" message when UseLoopSafepoints is disabled. Note
> 30:  *          that other parts of C2 assume that this option is enabled and might
> 31:  *          fail in more subtle ways otherwise.

Please make sure that this test does not trigger any of these other failures when executed in the CI.

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Marked as reviewed by thartmann (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1311