[PATCH] D87510: [SystemZ] Don't emit PC-relative memory accesses to unaligned (packed) symbols.

[Jonas Paulsson via Phabricator via llvm-commits]

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In the presence of packed structures (#pragma pack(1)) where elements are referenced through pointers, there will be stores/loads with alignment values matching the default alignments for the element types while the elements are in fact unaligned. Strictly speaking this is incorrect source code, but is unfortunately part of existing code and therefore now addressed.

This patch improves the pattern predicate for PC-relative loads and stores by not only checking the alignment value of the instruction, but also making sure that the symbol (and element) itself is aligned.

Fixes https://bugs.llvm.org/show_bug.cgi?id=44405


https://reviews.llvm.org/D87510

Files:
  llvm/lib/Target/SystemZ/SystemZISelDAGToDAG.cpp
  llvm/lib/Target/SystemZ/SystemZOperators.td
  llvm/test/CodeGen/SystemZ/int-move-10.ll

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