This is noted as a missing clang warning in #54222
(and we should still make that enhancement).
Alive2 proofs:
https://alive2.llvm.org/ce/z/Q8drDqhttps://alive2.llvm.org/ce/z/pE6LRt
I don't see a single conversion for all predicates
using "getFCmpCode" logic, so other predicates are
left as a TODO item.
Introduce a new attribute "function-inline-cost-multiplier" which
multiplies the inline cost of a call site (or all calls to a callee) by
the multiplier.
When processing the list of calls created by inlining, check each call
to see if the new call's callee is in the same SCC as the original
callee. If so, set the "function-inline-cost-multiplier" attribute of
the new call site to double the original call site's attribute value.
This does not happen when the original call site is intra-SCC.
This is an alternative to D120584, which marks the call sites as
noinline.
Hopefully fixes PR45253.
Reviewed By: davidxl
Differential Revision: https://reviews.llvm.org/D121084
The analysis passes output function name encapsulated in `'` braces,
but LV uses `"`. Harmonizing this may help in creating an update script
for the LV costmodel test checks.
Reviewed By: fhahn
Differential Revision: https://reviews.llvm.org/D121105
When decomposing constraints for unsigned conditions, we can use
negative values by zero-extending them, as long as they are less than
the maximum constraint value.
Fixes https://github.com/llvm/llvm-project/issues/54224
Add missing CanAdd check before adding a condition from an assume
to the successor blocks. When adding information from assume to
successor blocks we need to perform the same CanAdd as we do for adding
a condition from a branch.
Fixes https://github.com/llvm/llvm-project/issues/54217
Dropping this restriction seems to work fine (there are no assertion
failures), so it appears that either the updater got smarter or the
problematic cases are restricted elsewhere.
If doing this still causes issues, then the place to address it
would probably be 8f5bdaf481/llvm/lib/Transforms/IPO/Attributor.cpp (L1856-L1859),
which already prevents replacement outside the SCC, so I'm not
quite sure what this check is intended to avoid.
Differential Revision: https://reviews.llvm.org/D120987
Only determine the frame layout based on dereferenceable and align
attributes, and remove the type-based fallback, which is incompatible
with opaque pointers. The dereferenceable attribute is required,
while the align attribute uses default alignment of 1 (commonly,
align 1 attributes do not get placed, relying on default alignment).
The CoroSplit pass producing the resume function adds the necessary
attributes in 7daed35911/llvm/lib/Transforms/Coroutines/CoroSplit.cpp (L840),
and their presence is checked in coro-debug.ll at least.
Differential Revision: https://reviews.llvm.org/D120988
With opaque pointers, after splitRetconCoroutine() the FramePtr
may be an Argument rather than an Instruction. With typed pointers,
this currently doesn't happen because the FramePtr would be a
bitcast instruction.
Fix this by making FramePtr a Value and adding a helper for the
"after FramePtr" insertion point, which would be the start of the
function in the Argument case.
Differential Revision: https://reviews.llvm.org/D120994
This patch extends ConstraintElimination to also remove dead variables
when removing a constraint. When a constraint is removed because it is
out of scope, all new variables added for this constraint can also be
removed.
This keeps the total size of the systems much smaller, because it
reduces the number of variables drastically.
It also fixes a bug where variables where removed incorrectly.
Fixes https://github.com/llvm/llvm-project/issues/54228
Currently, we hardly ever actually run SCEV verification, even in
tests with -verify-scev. This is because the NewPM LPM does not
verify SCEV. The reason for this is that SCEV verification can
actually change the result of subsequent SCEV queries, which means
that you see different transformations depending on whether
verification is enabled or not.
To allow verification in the LPM, this limits verification to
BECounts that have actually been cached. It will not calculate
new BECounts.
BackedgeTakenInfo::getExact() is still not entirely readonly,
it still calls getUMinFromMismatchedTypes(). But I hope that this
is not problematic in the same way. (This could be avoided by
performing the umin in the other SCEV instance, but this would
require duplicating some of the code.)
Differential Revision: https://reviews.llvm.org/D120551
We already look through memory to determine where a value that is stored
might pop up again (potential copies). This patch introduces the other
direction with similar logic. If a value is loaded, we can follow all
the accesses to the pointer (or better object) and try to determine what
value might have been stored.
Both `undef` and `nullptr` are maximally aligned. This is especially
important as we often see `undef` until a proper value has been
identified during simplification.
With D106397 we used CFG reasoning to filter out writes that will not
interfere with a given load instruction. With this patch we use the
same logic (modulo the reversal in reachability check order) for store
instructions. As an example, we can now proof stores to shared memory
are dead if all the loads of the shared memory are not reachable from
them.
Heap-2-stack and heap-2-shared can replace an allocation call with
something else. To avoid us deriving information from the allocator
implementation we register a simplification callback now that will
force us to stop at the call site. We probably should create the
replacement memory eagerly and return that instead though.
While we can use range information when we derive dereferenceability we
must make sure to pick he right end of the range. Before we always went
with the minimal offset, which is not correct if we want to combine
the base dereferenceability with some offset. In that case it's the
maximum that gives the correct result.
Skip phi nodes in the preheader. They may not be considered loop
invariant by the assertion below.
Reviewed By: reames
Differential Revision: https://reviews.llvm.org/D121010
This ensures the right order in the sink-after map is maintained. If we
re-sink an instruction, it must be sunk after all earlier instructions
have been sunk.
Fixes https://github.com/llvm/llvm-project/issues/54223
There seems to be one more uncaught problem, SROA may now end up trying
to re-re-repromote the just-promoted shadow alloca, and do that endlessly.
This reverts commit adc0984d81f570ecc38ea23e7f556b95c7831e4c.
This is the second step in obviating two columns about allocation
functions in MemoryBuiltins.cpp.
Differential Revision: https://reviews.llvm.org/D119583
This is inspired by the original variant of D109749 by Graham Hunter,
but is a more general version.
Roughly, instead of promoting the alloca, we call it
a shadow/backing alloca, go through all it's slices,
clone(!) instructions that operated on it,
but make them operate on the cloned alloca,
and promote cloned alloca instead.
This keeps the shadow/backing alloca, and all the original instructions
around, which results in said shadow/backing alloca being
a perfect mirror/representation of the promoted alloca's content,
so calls that take the alloca as arguments (non-capturingly!)
can be supported.
For now, we require that the calls also don't modify the alloca's content,
but that is only to simplify the initial implementation,
and that will be supported in a follow-up.
Overall, this leads to *smaller* codesize:
https://llvm-compile-time-tracker.com/compare.php?from=a8b4f5bbab62091835205f3d648902432a4a5b58&to=aeae054055b125b011c1122f82c86457e159436f&stat=size-total
and is roughly neutral compile-time wise:
https://llvm-compile-time-tracker.com/compare.php?from=a8b4f5bbab62091835205f3d648902432a4a5b58&to=aeae054055b125b011c1122f82c86457e159436f&stat=instructions
This relands commit 703240c71fd640af7490069e8149d32d78d14da1,
that was reverted by commit 7405581f7ca3ba54be8a04c394a96fe6d980f073,
because the assertion `isa<LoadInst>(OrigInstr)` didn't hold in practice,
as the newly added test `@select_of_ptrs` shows:
If the pointers into alloca are used by select's/PHI's, then even if
we manage to fracture the alloca, some sub-alloca's will likely remain.
And if there are any non-capturing calls, then we will also decide to
keep the original backing alloca around, and we suddenly ~doubled
the alloca size, and the amount of memory traffic.
I'm not sure if this is a problem or we could live with it,
but let's leave that for later...
Reviewed By: djtodoro
Differential Revision: https://reviews.llvm.org/D113520
The custom state machine had a check for surplus threads that filtered
the main thread if the kernel was executed by a single warp only. We
now first check for the main thread, then for surplus threads, avoiding
to filter the former out.
Fixes#54214.
Reviewed By: jhuber6
Differential Revision: https://reviews.llvm.org/D121011
It caused builds to assert with:
(StackSize == 0 && "We already have the CFA offset!"),
function generateCompactUnwindEncoding, file AArch64AsmBackend.cpp, line 624.
when targeting iOS. See comment on the code review for reproducer.
> This patch rearranges emission of CFI instructions, so the resulting
> DWARF and `.eh_frame` information is precise at every instruction.
>
> The current state is that the unwind info is emitted only after the
> function prologue. This is fine for synchronous (e.g. C++) exceptions,
> but the information is generally incorrect when the program counter is
> at an instruction in the prologue or the epilogue, for example:
>
> ```
> stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
> mov x29, sp
> .cfi_def_cfa w29, 16
> ...
> ```
>
> after the `stp` is executed the (initial) rule for the CFA still says
> the CFA is in the `sp`, even though it's already offset by 16 bytes
>
> A correct unwind info could look like:
> ```
> stp x29, x30, [sp, #-16]! // 16-byte Folded Spill
> .cfi_def_cfa_offset 16
> mov x29, sp
> .cfi_def_cfa w29, 16
> ...
> ```
>
> Having this information precise up to an instruction is useful for
> sampling profilers that would like to get a stack backtrace. The end
> goal (towards this patch is just a step) is to have fully working
> `-fasynchronous-unwind-tables`.
>
> Reviewed By: danielkiss, MaskRay
>
> Differential Revision: https://reviews.llvm.org/D111411
This reverts commit 32e8b550e5439c7e4aafa73894faffd5f25d0d05.
Prior to this change LLVM would happily elide a call to any allocation
function and a call to any free function operating on the same unused
pointer. This can cause problems in some obscure cases, for example if
the body of operator::new can be inlined but the body of
operator::delete can't, as in this example from jyknight:
#include <stdlib.h>
#include <stdio.h>
int allocs = 0;
void *operator new(size_t n) {
allocs++;
void *mem = malloc(n);
if (!mem) abort();
return mem;
}
__attribute__((noinline)) void operator delete(void *mem) noexcept {
allocs--;
free(mem);
}
void deleteit(int*i) { delete i; }
int main() {
int*i = new int;
deleteit(i);
if (allocs != 0)
printf("MEMORY LEAK! allocs: %d\n", allocs);
}
This patch addresses the issue by introducing the concept of an
allocator function family and uses it to make sure that alloc/free
function pairs are only removed if they're in the same family.
Differential Revision: https://reviews.llvm.org/D117356
Previous and OhterPrev may not be in the same block. Use DT::dominates
instead of local comesBefore. DT::dominates is already used earlier to
check the order of Previous and SinkCandidate.
Fixes https://github.com/llvm/llvm-project/issues/54195
Recommit without changes over 53abe3ff66a54117308352d379837c7d3229f8d6,
which addressed the cause of the reported crash.
-----
With opaque pointers, the zero-offset load will generally not use
a GEP. Allow a direct load without GEP, which is treated the same
way as a zero-offset GEP.
Use the overload that support moving into an empty block. I don't
think that this situation can occur right now, but it can happen
with the change from e7fb1c15cb85d748c1c4fdd5a2eb5613ec7bef1d,
and the test is derived from the issue reported there.
This reverts commit 169ebf03ab2a6f16bfa32a36305929c7bc8e4784.
This was effectively rendering the attribute useless in the real
world, although this is still broken.
This reverts commit 30e8f83c84c5a302a559722fc0d2973dc3f425ee.
Causes huge compile time regressions on certain large files. Will followup offline with author.
This patch extends first-order recurrence handling to support cases
where we already sunk an instruction for a different recurrence, but
LastPrev comes before Previous.
To handle those cases correctly, we need to find the earliest entry for
the sink-after chain, because this is references the Previous from the
original recurrence. This is needed to ensure we use the correct
instruction as sink point.
Depends on D118558.
Reviewed By: Ayal
Differential Revision: https://reviews.llvm.org/D118642
The costs of vector shifts was 2 as opposed to 1, as the nodes are
marked custom. Fix this like the others and mark the nodes as cheap.
Differential Revision: https://reviews.llvm.org/D120773
To make this actually trigger, we also need to check whether the
function types differ, which is a hidden cast under opaque pointers.
The transform is somewhat less relevant there because it is
primarily about pointer bitcasts, but it can also happen with other
bit- or pointer-castable types.
Byval handling is easier with opaque pointers because there is no
need to adjust the byval type, we only need to make sure that it's
still a pointer.
The logic for handling this was fixed in
8d7f118ab2b9e51d6cf2811291e319b4d977eb8c, but the check for byval
on the callee was retained. This resulted in a weird situation
where the transform would work depending on whether the byval
was only on the call or on both the call and the function.
