[PATCH] D9887: [DebugInfo][FastISel] Prevent using debug location from previous block for local values

[David Blaikie via llvm-commits]

dblaikie requested changes to this revision.
dblaikie added a comment.
This revision now requires changes to proceed.

(un-accept, didn't mean to override some of the thread context & I missed it while reading back over this - so going back to a "discussion" state)

my basic thinking is: We know some instructions will never have locations on them (synthesized instructions for various reasons, etc) & if those instructions ever end up at the start of a block we'll probably get bad behavior (because they'll be assigned to whatever location is at the end of the block that happens to be laid out prior to this one) so we'll want this backpropagation regardless of any fixes we make to constants.

Yes, putting single-use constants at their use would be nice/good/better (especially for things like asan), maybe even putting multi-use constants at their first use (is that always possible, though? do we ever propagate a constant load from two basic blocks into a common prior block for example?) if possible.


Repository:
  rL LLVM

http://reviews.llvm.org/D9887