[all-commits] [llvm/llvm-project] 451799: [IRMover] Remove UB implying parameter attributes ...

[Tim Neumann via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 451799bb8261bde52bbfef226d019caf1d82aa42
      https://github.com/llvm/llvm-project/commit/451799bb8261bde52bbfef226d019caf1d82aa42
  Author: Tim Neumann <timnn at google.com>
  Date:   2023-02-21 (Tue, 21 Feb 2023)

  Changed paths:
    M llvm/include/llvm/IR/Attributes.h
    M llvm/lib/Linker/IRMover.cpp
    A llvm/test/Transforms/FunctionImport/Inputs/attr_fixup_dae_noundef.ll
    A llvm/test/Transforms/FunctionImport/attr_fixup_dae_noundef.ll

  Log Message:
  -----------
  [IRMover] Remove UB implying parameter attributes when necessary

When importing functions from some module X into some module Y, they may reference other functions already present in Y. The signature (especially attributes) of those other functions may have diverged between X and Y (e.g. due to the Dead Argument Elimination optimization). If necessary, modify the attributes to avoid UB.

See the added test and implementation comments for more details.

This was exposed by https://reviews.llvm.org/D133036 before it was reverted. Fixes https://github.com/llvm/llvm-project/issues/58976.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D139209