Skip NULLCHK that has already been optimized away in Loop Versioner #4294
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In TR_LoopVersioner::versionNaturalLoop, a NULLCHK might be specialized away. However, it will still appear among the list of treetops in nullCheckTrees. When subsequent operations iterate over that list, they must skip NULLCHK nodes that no longer take effect. Signed-off-by: Henry Zongaro <zongaro@ca.ibm.com>
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Vijay @vijaysun-omr and Liqun @liqunl, may I ask you to review? I've just submitted a personal build to test out this change. |
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Looks good to me. |
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@genie-omr build all |
vijaysun-omr
approved these changes
Sep 11, 2019
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AppVeyor build failed due to infrastructural issues so I restarted it. |
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This is a pretty safe change; it just checks if the entry in the list of null check trees still has the opcode that is expected (namely a null check) before going forward. The case when it may not be a null check was investigated and we can skip processing the entry in the list in that case and so that's what is being done via this commit. Checks have also passed. I am merging this. |
vijaysun-omr
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In
TR_LoopVersioner::versionNaturalLoop, aNULLCHKmight be specialized away. However, it will still appear among the list of treetops that are tracked innullCheckTrees. When subsequent operations iterate over that list, they must skipNULLCHKnodes that no longer take effect.Signed-off-by: Henry Zongaro zongaro@ca.ibm.com