Max Kazantsev 2a184af221 [IndVars] Fix corner case with unreachable Phi inputs. PR40454 ...

Logic in `getInsertPointForUses` doesn't account for a corner case when `Def`
only comes to a Phi user from unreachable blocks. In this case, the incoming
value may be arbitrary (and not even available in the input block) and break
the loop-related invariants that are asserted below.

In fact, if we encounter this situation, no IR modification is needed. This
Phi will be simplified away with nearest cleanup.

Differential Revision: https://reviews.llvm.org/D58045
Reviewed By: spatel

llvm-svn: 353816

2019-02-12 09:59:44 +00:00

106 KiB

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