RFR: 8275202: C2: optimize out more redundant conditions

[Roland Westrelin]

On Fri, 6 Oct 2023 04:24:43 GMT, Dean Long <dlong at openjdk.org> wrote:

> For some reason the new tests under test/hotspot/jtreg/compiler/loopconditionalpropagation are passing, even without these new changes.

I added those tests for issues I ran into while working on the patch. They are bugs that were introduced by the patch (and that I then fixed) but that I found to be tricky enough to get right that I thought it was best to have a test for them.
`compiler/c2/irTests/TestLoopConditionalPropagation.java`, the one that verifies that the patch optimizes code better, fails without the patch.

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PR Comment: https://git.openjdk.org/jdk/pull/14586#issuecomment-1752503277