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[Attributor] Really use the executed-context

Authored by jdoerfert on Oct 30 2019, 3:21 PM.

Description

[Attributor] Really use the executed-context

Before we did not follow casts and geps when we looked at the users of a
pointer in the pointers must-be-executed-context. This caused us to fail
to determine if it was accessed for sure. With this change we follow
such users now.

The above extension exposed problems in getKnownNonNullAndDerefBytesForUse
which did not always check what the base pointer was. We also did not
handle negative offsets as conservative as we have to without explicit
loop handling. Finally, we should not derive a huge number if we access
a pointer that was traversed backwards first.

The problems exposed by this functional change are already tested in the
existing test cases as is the functional change.

Differential Revision: https://reviews.llvm.org/D69647

Details

Committed
jdoerfertOct 31 2019, 1:09 PM
Differential Revision
D69647: [Attributor] Really use the executed-context
Parents
rG70ad617dd645: [SLP] Vectorize jumbled stores.
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