There was some ad-hoc handling of liveness and manifest to avoid
breaking CGSCC guarantees. Things always slipped through though.
This cleanup will:
1) Prevent us from manifesting any "information" outside the CGSCC.
This might be too conservative but we need to opt-in to annotation
not try to avoid some problematic ones.
2) Avoid running any liveness analysis outside the CGSCC. We did have
some AAIsDeadFunction handling to this end but we need this for all
AAIsDead classes. The reason is that AAIsDead information is only
correct if we actually manifest it, since we don't (see point 1) we
cannot actually derive/use it at all. We are currently trying to
avoid running any AA updates outside the CGSCC but that seems to
impact things quite a bit.
3) Assert, don't check, that our modifications (during cleanup) modifies
only CGSCC functions.
genericValueTraversal can look through arguments and allow value
simplification across function boundaries. In fact, the latter already
happened unchecked. With this change we allow the user of
genericValueTraversal to opt-out of interprocedural traversal if
required. We explicitly look through arguments now which helps to do
various things, incl. the propagation of constants into OpenMP parallel
regions (on the host).
This fixes a conceptual problem with our AAIsDead usage which conflated
call site liveness with call site return value liveness. Without the
fix tests would obviously miscompile as we make genericValueTraversal
more powerful (in a follow up). The effects on the tests are mixed but
mostly marginal. The most prominent one is the lack of `noreturn` for
functions. The reason is that we make entire blocks live at the same
time (for time reasons). Now that we actually look at the block
liveness, which we need to do, the return instructions are live and
will survive. As an example, `noreturn_async.ll` has been modified
to retain the `noreturn` even with block granularity. We could address
this easily but there is little need in practice.
Make use of the getGEPIndicesForOffset() helper for creating GEPs.
This handles arrays as well, uses correct GEP index types and
reduces code duplication.
Differential Revision: https://reviews.llvm.org/D112263
This patch introduces AAPointerInfo which tracks the uses of a pointer
and places them in "bins" based on their offset from the base and access
size.
As with other AAs, any pointer can be tracked but it is up to the user
to make sense of the results. The user in this patch is AAValueSimplify
and AAPotentialValues which both utilize AAPointerInfo to determine the
value of a load. For now, this is restricted to loads of allocas and
internal globals. Through the use of AAPointerInfo and the "bins" we can
track struct members separately. The users also know that storing only
zeros (at unknown indices) will result in loading only 0 (from unknown
indices). Other than that, the users are flow and context insensitive
(for now).
To deal with the "bins" more easily, AAPointerInfo provides a
forallInterfearingAccesses that applies a callback on all accesses
that might interfere with a given load or store.
Differential Revision: https://reviews.llvm.org/D104432
The update_test_checks script can now check for global symbols and is able
to handle them properly when they differ across prefixes, e.g.,
attribute #0 might be different in different runs.
This patch simply updates all the Attributor tests with the new script.
Reviewed By: sstefan1
Differential Revision: https://reviews.llvm.org/D97906
When we promote pointer arguments we did compute a wrong offset and use
a wrong type for the array case.
Bug reported and reduced by Whitney Tsang <whitneyt@ca.ibm.com>.
