[PATCH] D107016: [DebugInfo][LoopStrengthReduction] Ensure restoration of cached DIExpression when using SCEV-based salvaging

[Chris Jackson via Phabricator via llvm-commits]

chrisjackson added a comment.

Thanks for the comments. I think the test i mentioned is restricted to internal LSR salvages that modify the number of location operands as well as the the DIExpression. This patch adds restoration of the DIExpression when the number of location operands has not been modified, but the single operand and the DIExpression have been modified,. I'm not sure how easy it is to craft a test that elicits that behaviour from LSR. To me this patch is defence against such modifications of the dbg.value by LSR. 
I think this patch introduces safer behaviour, as although LSR may not modify DIExpressions of single location operand dbg.value at the moment, it may do in future. I hope I'm making sense.


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https://reviews.llvm.org/D107016