[PATCH] D39404: DAG: Add nuw when splitting loads and stores

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
Herald added subscribers: tpr, wdng.

The object can't straddle the address space
wrap around, so I think it's OK to assume any
offsets added to the base object pointer can't
overflow. Similar logic already appears to be
applied in SelectionDAGBuilder when lowering
aggregate returns. Overflow flags scare me
so I'm not sure. I'm not sure the best
way to test for these, but some of these
avoid AMDGPU test regressions in a future
commit.

      

It would probably make sense to introduce
a getAddNUW helper for this instead
of littering the same boilerplate around
to create the flags.


https://reviews.llvm.org/D39404

Files:
  lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
  lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
  lib/CodeGen/SelectionDAG/TargetLowering.cpp

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