[all-commits] [llvm/llvm-project] e39e2b: [DebugInfo] Prevent invalid fragments at ISel from...

[Stephen Tozer via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: e39e2b4a79c6645a85f0aee5b1e9e6d5d917033a
      https://github.com/llvm/llvm-project/commit/e39e2b4a79c6645a85f0aee5b1e9e6d5d917033a
  Author: stozer <stephen.tozer at sony.com>
  Date:   2019-12-12 (Thu, 12 Dec 2019)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    A llvm/test/CodeGen/ARM/debuginfo-split-carryexpr.ll

  Log Message:
  -----------
  [DebugInfo] Prevent invalid fragments at ISel from dropping debug info

During SelectionDAG, if a value which is associated with a DBG_VALUE
needs to be split across multiple registers, the DBG_VALUE will be split
into a set of fragment expressions to recreate the original value.

If one or more of these fragments cannot be created, they would
previously be silently dropped, causing the old debug value to live past
its expiry date. This patch fixes this issue by keeping invalid
fragments while setting their value as Undef.

Differential revision: https://reviews.llvm.org/D70248