[PATCH] D59417: [GVN] Add default debug location when constructing PHI nodes

[David Blaikie via Phabricator via llvm-commits]

dblaikie added a comment.

Does this need to be line zero, or could it be no location (the absence of a dbgloc)?

Zero is necessary for inlinable calls (since they can't have no dbgloc - for long standing reasons) or I guess for some other cases where we want to be very clear that this instruction isn't from this line of code. But otherwise it's generally acceptable to have no location (which is what debug loc merging does except for calls) & let any machine code end up with the location of the preceeding instructions.

Using zero locations can/will grow the line table size (having to describe different locations (zero, no-zero, zero, non-zero) for finer slices of the instruction stream) and potentially make debugging more difficult (depending on how the consumers renders this experience to users).


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  https://reviews.llvm.org/D59417/new/

https://reviews.llvm.org/D59417