[PATCH] D106447: [DAGCombine] DAGTypeLegalizer::GenWidenVectorLoads(): make use of dereferenceability knowledge

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added inline comments.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp:5336
+      NumDereferenceableBytes = std::max<unsigned>(
+          NumDereferenceableBytes, cast<LoadSDNode>(LdOp)->getAlignment());
+    } else
----------------
Ugh, actually, this is still not quite right, because it should be the alignment of the load we will produce now, not of the one we just produced.


================
Comment at: llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp:5342-5344
     Align NewAlign = ScaledOffset == 0
                          ? LD->getOriginalAlign()
                          : commonAlignment(LD->getAlign(), ScaledOffset);
----------------
lebedev.ri wrote:
> This really doesn't look right
Disregard, alignment tracking in SDAG is confusing.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D106447/new/

https://reviews.llvm.org/D106447