[jdk11u-dev] Integrated: 8284358: Unreachable loop is not removed from C2 IR, leading to a broken graph

[Goetz Lindenmaier]

On Tue, 11 Oct 2022 15:28:01 GMT, Goetz Lindenmaier <goetz at openjdk.org> wrote:

> I backport this for parity with 11.0.18-oracle.
> 
> I had to resolve this.
> The only reason for this I spotted is the difference
> in this comment:
> // Eagerly replace phis with top to avoid regionless phis.
> 
> I added include vectset.hpp.
> 
> The new code needs set_req_X with argument PhaseGVN.
> I added 
>   void set_req_X( uint i, Node *n, PhaseGVN *igvn );
>   to node.hpp and the implementation to phaseX.cpp.
> 
> I added an arena to the VectorSet constructor.
> 
> Flag StressIGVN is not available in 11.
> I removed it from the test and reduced the
> test cases accordingly.
> Test passes with and without the fix.

This pull request has now been integrated.

Changeset: 7655988e
Author:    Goetz Lindenmaier <goetz at openjdk.org>
URL:       https://git.openjdk.org/jdk11u-dev/commit/7655988ef4f39809f724eba35ab378a36e084840
Stats:     294 lines in 4 files changed: 255 ins; 3 del; 36 mod

8284358: Unreachable loop is not removed from C2 IR, leading to a broken graph

Reviewed-by: mdoerr
Backport-of: 95497772e7207b5752e6ecace4a6686df2b45227

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PR: https://git.openjdk.org/jdk11u-dev/pull/1443