Revert "[Attributor] Teach AAPointerInfo to look into aggregates"
This reverts commit 844f6c5d03 and
4ed0a88cd8 as they broke the buildbots
that run openmp/libomptarget/test/offloading/bug49021.cpp.
If we have a constant aggregate, e.g., as an initializer, we usually
failed to extract the proper value/type from it. This patch provides the
size and offset information necessary to extract the right part of the
constant.
This patch replaces calls to greatestCommonDivisor with std::gcd where
both arguments are known to be of unsigned. This means that
std::common_type_t of the two argument types should just be the wider
one of the two.
The relevant property of allocation functions of interest here is
their uniqueness (in the sense of disjoint provenance), which is
encoded by the noalias return attribute.
Differential Revision: https://reviews.llvm.org/D130225
In contrast to AAPotentialValues, the constant values version can
contain implicit `undef` in the set. We had an assertion that could
misfire before. Handle it properly now.
If we look at a write, we should not enact the "has been written to"
logic introduced to avoid spurious write -> read dependences. Doing so
lead to elimination of stores we needed, which is obviously bad.
If a function is non-recursive we only performed intra-procedural
reasoning for reachability (via AA::isPotentiallyReachable). However,
if it is re-entrant that doesn't mean we can't reach. Instead of this
problematic logic in the reachability reasoning we utilize logic in
AAPointerInfo. If a location is for sure written by a function it can
be re-entrant or recursive we know only intra-procedural reasoning is
sufficient.
If we have a dominating must-write access we do not need to know the
initial value of some object to perform reasoning about the potential
values. The dominating must-write has overwritten the initial value.
We currently assume in a number of places that free-like functions
free their first argument. This is true for all hardcoded free-like
functions, but with the new attribute-based design, the freed
argument is supposed to be indicated by the allocptr attribute.
To make sure we handle this correctly once allockind(free) is
respected, add a getFreedOperand() helper which returns the freed
argument, rather than just indicating whether the call frees *some*
argument.
This migrates most but not all users of isFreeCall() to the new
API. The remaining users are a bit more tricky.
We were quite conservative when it came to PHI node handling to avoid
recursive reasoning. Now we check more direct if we have seen a PHI
already or not. This allows non-recursive PHI chains to be handled.
This also exposed a bug as we did only model the effect of one loop
traversal. `phi_no_store_3` has been adapted to show how we would have
used `undef` instead of `1` before. With this patch we don't replace
it at all, which is expected as we do not argue about loop iterations
(or alignments).
For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many reasons:
- We recomputed the result a lot as there was no caching for the 9
locations calling `genericValueTraversal`.
- We added the idea of "intra" vs. "inter" procedural simplification
only as an afterthought. `genericValueTraversal` did offer an option
but `AAValueSimplify` did not. Thus, we might end up with "too much"
simplification in certain situations and then gave up on it.
- Because `genericValueTraversal` was not a real `AA` we ended up with
problems like the infinite recursion bug (#54981) as well as code
duplication.
This patch introduces `AAPotentialValues` and replaces the
`AAValueSimplify` uses with it. `genericValueTraversal` is folded into
`AAPotentialValues` as are the instruction simplifications performed in
`AAValueSimplify` before. We further distinguish "intra" and "inter"
procedural simplification now.
`AAValueSimplify` was not deleted as we haven't ported the
re-materialization of instructions yet. There are other differences over
the former handling, e.g., we may not fold trivially foldable
instructions right now, e.g., `add i32 1, 1` is not folded to `i32 2`
but if an operand would be simplified to `i32 1` we would fold it still.
We are also even more aware of function/SCC boundaries in CGSCC passes,
which is good even if some tests look like they regress.
Fixes: https://github.com/llvm/llvm-project/issues/54981
Note: A previous version was flawed and consequently reverted in
6555558a80.
I have no idea what's going on here. This code was moved
around/introduced in change cb26b01d57 and starts crashing with a NULL
dereference once I apply https://reviews.llvm.org/D123090. I assume that
I've unwittingly taught the attributor enough that it's able to do more
clever things than in the past, and it's able to trip on this case. I
make no claims about the correctness of this patch, but it passes tests
and seems to fix all the crashes I've been seeing.
Differential Revision: https://reviews.llvm.org/D129589
For the longest time we used `AAValueSimplify` and
`genericValueTraversal` to determine "potential values". This was
problematic for many reasons:
- We recomputed the result a lot as there was no caching for the 9
locations calling `genericValueTraversal`.
- We added the idea of "intra" vs. "inter" procedural simplification
only as an afterthought. `genericValueTraversal` did offer an option
but `AAValueSimplify` did not. Thus, we might end up with "too much"
simplification in certain situations and then gave up on it.
- Because `genericValueTraversal` was not a real `AA` we ended up with
problems like the infinite recursion bug (#54981) as well as code
duplication.
This patch introduces `AAPotentialValues` and replaces the
`AAValueSimplify` uses with it. `genericValueTraversal` is folded into
`AAPotentialValues` as are the instruction simplifications performed in
`AAValueSimplify` before. We further distinguish "intra" and "inter"
procedural simplification now.
`AAValueSimplify` was not deleted as we haven't ported the
re-materialization of instructions yet. There are other differences over
the former handling, e.g., we may not fold trivially foldable
instructions right now, e.g., `add i32 1, 1` is not folded to `i32 2`
but if an operand would be simplified to `i32 1` we would fold it still.
We are also even more aware of function/SCC boundaries in CGSCC passes,
which is good even if some tests look like they regress.
Fixes: https://github.com/llvm/llvm-project/issues/54981
Note: A previous version was flawed and consequently reverted in
6555558a80.
We recently learned to place the alloca during the heap2stack
transformation in the entry block but we did not account for other
concurrent modifications. We need to record our decision rather than
checking (then outdated) passes during the manifest stage. This will
also allow us to use a custom (=optimistic) "loop info" in the future.
As integer div/rem constant expressions are no longer supported,
constants can no longer trap and are always safe to speculate.
Remove the Constant::canTrap() method and its usages.
If we are certainly not in a loop we can directly emit the heap2stack
allocas in the function entry block. This will help to get rid of them
(SROA) and avoid stacksave/restore intrinsics when the function is
inlined.
The `isDenselyPacked` static member of the `ArgumentPromotionPass` class
is not used in the class itself anymore. The single known user of the
function is in the `AttributorAttributes.cpp` file, so the function has
been moved into the file.
Differential Revision: https://reviews.llvm.org/D128725
This avoid creating empty bins in AAPointerInfo which can lead to
segfaults. Also ensure we do not try to translate from callee to caller
except if we really take the argument state and move it to the call site
argument state.
Fixes: https://github.com/llvm/llvm-project/issues/55726
`llvm::max(Align, MaybeAlign)` and `llvm::max(MaybeAlign, Align)` are
not used often enough to be required. They also make the code more opaque.
Differential Revision: https://reviews.llvm.org/D128121
Johannes Doerfert