We want the test to remain good anyway.
I think the fix is incoming.
This reverts part of commit rL337344.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337359 91177308-0d34-0410-b5e6-96231b3b80d8
InstCombine has a cast transform that matches a cast-of-select:
Orig = cast (Src = select Cond TV FV)
And tries to replace it with a select which has the cast folded in:
NewSel = select Cond (cast TV) (cast FV)
The combiner does RAUW(Orig, NewSel), so any debug values for Orig would
survive the transform. But debug values for Src would be lost.
This patch teaches InstCombine to replace all debug uses of Src with
NewSel (taking care of doing any necessary DIExpression rewriting).
Differential Revision: https://reviews.llvm.org/D49270
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337310 91177308-0d34-0410-b5e6-96231b3b80d8
Once we resolved an undef in a function we can run Solve, which could
lead to finding a constant return value for the function, which in turn
could turn undefs into constants in other functions that call it, before
resolving undefs there.
Computationally the amount of work we are doing stays the same, just the
order we process things is slightly different and potentially there are
a few less undefs to resolve.
We are still relying on the order of functions in the IR, which means
depending on the order, we are able to resolve the optimal undef first
or not. For example, if @test1 comes before @testf, we find the constant
return value of @testf too late and we cannot use it while solving
@test1.
This on its own does not lead to more constants removed in the
test-suite, probably because currently we have to be very lucky to visit
applicable functions in the right order.
Maybe we manage to come up with a better way of resolving undefs in more
'profitable' functions first.
Reviewers: efriedma, mssimpso, davide
Reviewed By: efriedma, davide
Differential Revision: https://reviews.llvm.org/D49385
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337283 91177308-0d34-0410-b5e6-96231b3b80d8
TTI::getMinMaxReductionCost typically can't handle pointer types - until this is changed its better to limit horizontal reduction to integer/float vector types only.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337280 91177308-0d34-0410-b5e6-96231b3b80d8
Finish same optimization for add instruction in D49216 and sdiv instruction in
D49382. This patch is for srem instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337270 91177308-0d34-0410-b5e6-96231b3b80d8
We are using i8 for these tests, and shifting by 4,
which is exactly the half of i8.
But as it is seen from the proofs https://rise4fun.com/Alive/mgu
KeptBits = bitwidth(%x) - MaskedBits,
so with using shifts by 4, we are not really testing that
we actually properly handle the other cases with shifts not by half...
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337208 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
[[ https://bugs.llvm.org/show_bug.cgi?id=38149 | PR38149 ]]
As discussed in https://reviews.llvm.org/D49179#1158957 and later,
the IR for 'check for [no] signed truncation' pattern can be improved:
https://rise4fun.com/Alive/gBf
^ that pattern will be produced by Implicit Integer Truncation sanitizer,
https://reviews.llvm.org/D48958https://bugs.llvm.org/show_bug.cgi?id=21530
in signed case, therefore it is probably a good idea to improve it.
Proofs for this transform: https://rise4fun.com/Alive/mgu
This transform is surprisingly frustrating.
This does not deal with non-splat shift amounts, or with undef shift amounts.
I've outlined what i think the solution should be:
```
// Potential handling of non-splats: for each element:
// * if both are undef, replace with constant 0.
// Because (1<<0) is OK and is 1, and ((1<<0)>>1) is also OK and is 0.
// * if both are not undef, and are different, bailout.
// * else, only one is undef, then pick the non-undef one.
```
The DAGCombine will reverse this transform, see
https://reviews.llvm.org/D49266
Reviewers: spatel, craig.topper
Reviewed By: spatel
Subscribers: JDevlieghere, rkruppe, llvm-commits
Differential Revision: https://reviews.llvm.org/D49320
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337190 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r337081, therefore restoring r337050 (and fix in
r337059), with test fix for bot failure described after the original
description below.
In order to always import the same copy of a linkonce function,
even when encountering it with different thresholds (a higher one then a
lower one), keep track of the summary we decided to import.
This ensures that the backend only gets a single definition to import
for each GUID, so that it doesn't need to choose one.
Move the largest threshold the GUID was considered for import into the
current module out of the ImportMap (which is part of a larger map
maintained across the whole index), and into a new map just maintained
for the current module we are computing imports for. This saves some
memory since we no longer have the thresholds maintained across the
whole index (and throughout the in-process backends when doing a normal
non-distributed ThinLTO build), at the cost of some additional
information being maintained for each invocation of ComputeImportForModule
(the selected summary pointer for each import).
There is an additional map lookup for each callee being considered for
importing, however, this was able to subsume a map lookup in the
Worklist iteration that invokes computeImportForFunction. We also are
able to avoid calling selectCallee if we already failed to import at the
same or higher threshold.
I compared the run time and peak memory for the SPEC2006 471.omnetpp
benchmark (running in-process ThinLTO backends), as well as for a large
internal benchmark with a distributed ThinLTO build (so just looking at
the thin link time/memory). Across a number of runs with and without
this change there was no significant change in the time and memory.
(I tried a few other variations of the change but they also didn't
improve time or peak memory).
The new commit removes a test that no longer makes sense
(Transforms/FunctionImport/hotness_based_import2.ll), as exposed by the
reverse-iteration bot. The test depends on the order of processing the
summary call edges, and actually depended on the old problematic
behavior of selecting more than one summary for a given GUID when
encountered with different thresholds. There was no guarantee even
before that we would eventually pick the linkonce copy with the hottest
call edges, it just happened to work with the test and the old code, and
there was no guarantee that we would end up importing the selected
version of the copy that had the hottest call edges (since the backend
would effectively import only one of the selected copies).
Reviewers: davidxl
Subscribers: mehdi_amini, inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D48670
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337184 91177308-0d34-0410-b5e6-96231b3b80d8
Bug fix for PR37808. The regression test is a reduced version of the
original reproducer attached to the bug report. As stated in the report,
the problem was that InsertedPHIs was keeping dangling pointers to
deleted Memory-Phis. MemoryPhis are created eagerly and sometimes get
zapped shortly afterwards. I've used WeakVH instead of an expensive
removal operation from the active workset.
Differential Revision: https://reviews.llvm.org/D48372
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337149 91177308-0d34-0410-b5e6-96231b3b80d8
This fold is repeated/misplaced in instcombine, but I'm
not sure if it's safe to remove that yet because some
other folds appear to be asserting that the transform
has occurred within instcombine itself.
This isn't the best fix for PR37776, but it probably
hides the bug with the given code example:
https://bugs.llvm.org/show_bug.cgi?id=37776
We have another test to demonstrate the more general bug.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337127 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commits r337050 and r337059. Caused failure in
reverse-iteration bot that needs more investigation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337081 91177308-0d34-0410-b5e6-96231b3b80d8
Add -debug-only=function-import to get more information for debugging
reverse-iteration bot failure from r337050.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337076 91177308-0d34-0410-b5e6-96231b3b80d8
In order to always import the same copy of a linkonce function,
even when encountering it with different thresholds (a higher one then a
lower one), keep track of the summary we decided to import.
This ensures that the backend only gets a single definition to import
for each GUID, so that it doesn't need to choose one.
Move the largest threshold the GUID was considered for import into the
current module out of the ImportMap (which is part of a larger map
maintained across the whole index), and into a new map just maintained
for the current module we are computing imports for. This saves some
memory since we no longer have the thresholds maintained across the
whole index (and throughout the in-process backends when doing a normal
non-distributed ThinLTO build), at the cost of some additional
information being maintained for each invocation of ComputeImportForModule
(the selected summary pointer for each import).
There is an additional map lookup for each callee being considered for
importing, however, this was able to subsume a map lookup in the
Worklist iteration that invokes computeImportForFunction. We also are
able to avoid calling selectCallee if we already failed to import at the
same or higher threshold.
I compared the run time and peak memory for the SPEC2006 471.omnetpp
benchmark (running in-process ThinLTO backends), as well as for a large
internal benchmark with a distributed ThinLTO build (so just looking at
the thin link time/memory). Across a number of runs with and without
this change there was no significant change in the time and memory.
(I tried a few other variations of the change but they also didn't
improve time or peak memory).
Reviewers: davidxl
Subscribers: mehdi_amini, inglorion, llvm-commits
Differential Revision: https://reviews.llvm.org/D48670
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337050 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Currently LowerTypeTests emits jumptable entries for all live external
and address-taken functions; however, we could limit the number of
functions that we emit entries for significantly.
For Cross-DSO CFI, we continue to emit jumptable entries for all
exported definitions. In the non-Cross-DSO CFI case, we only need to
emit jumptable entries for live functions that are address-taken in live
functions. This ignores exported functions and functions that are only
address taken in dead functions. This change uses ThinLTO summary data
(now emitted for all modules during ThinLTO builds) to determine
address-taken and liveness info.
The logic for emitting jumptable entries is more conservative in the
regular LTO case because we don't have summary data in the case of
monolithic LTO builds; however, once summaries are emitted for all LTO
builds we can unify the Thin/monolithic LTO logic to only use summaries
to determine the liveness of address taking functions.
This change is a partial fix for PR37474. It reduces the build size for
nacl_helper by ~2-3%, the reduction is due to nacl_helper compiling in
lots of unused code and unused functions that are address taken in dead
functions no longer being being considered live due to emitted jumptable
references. The reduction for chromium is ~0.1-0.2%.
Reviewers: pcc, eugenis, javed.absar
Reviewed By: pcc
Subscribers: aheejin, dexonsmith, dschuff, mehdi_amini, eraman, steven_wu, llvm-commits, kcc
Differential Revision: https://reviews.llvm.org/D47652
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337038 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r336419: use-after-free on CallGraph::FunctionMap elements
due to the use of a stale iterator in CGPassManager::runOnModule.
The iterator may be invalidated if a pass removes a function, ex.:
llvm::LegacyInlinerBase::inlineCalls
inlineCallsImpl
llvm::CallGraph::removeFunctionFromModule
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337018 91177308-0d34-0410-b5e6-96231b3b80d8
We currently only support binary instructions in the alternate opcode shuffles.
This patch is an initial attempt at adding cast instructions as well, this raises several issues that we probably want to address as we continue to generalize the alternate mechanism:
1 - Duplication of cost determination - we should probably add scalar/vector costs helper functions and get BoUpSLP::getEntryCost to use them instead of determining costs directly.
2 - Support alternate instructions with the same opcode (e.g. casts with different src types) - alternate vectorization of calls with different IntrinsicIDs will require this.
3 - Allow alternates to be a different instruction type - mixing binary/cast/call etc.
4 - Allow passthrough of unsupported alternate instructions - related to PR30787/D28907 'copyable' elements.
Reapplied with fix to only accept 2 different casts if they come from the same source type (PR38154).
Differential Revision: https://reviews.llvm.org/D49135
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336989 91177308-0d34-0410-b5e6-96231b3b80d8
This bug was created by rL335258 because we used to always call instsimplify
after trying the associative folds. After that change it became possible
for subsequent folds to encounter unsimplified code (and potentially assert
because of it).
Instead of carrying changed state through instcombine, we can just return
immediately. This allows instsimplify to run, so we can continue assuming
that easy folds have already occurred.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336965 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This patch is crucial for proving equality laundered/stripped
pointers. eg:
bool foo(A *a) {
return a == std::launder(a);
}
Clang with -fstrict-vtable-pointers will emit something like:
define dso_local zeroext i1 @_Z3fooP1A(%struct.A* %a) {
entry:
%c = bitcast %struct.A* %a to i8*
%call = tail call i8* @llvm.launder.invariant.group.p0i8(i8* %c)
%0 = bitcast %struct.A* %a to i8*
%1 = tail call i8* @llvm.strip.invariant.group.p0i8(i8* %0)
%2 = tail call i8* @llvm.strip.invariant.group.p0i8(i8* %call)
%cmp = icmp eq i8* %1, %2
ret i1 %cmp
}
and because %2 can be replaced with @llvm.strip.invariant.group(%0)
and that %2 and %1 will produce the same value (because strip is readnone)
we can replace compare with true.
Reviewers: rsmith, hfinkel, majnemer, amharc, kuhar
Subscribers: llvm-commits, hiraditya
Differential Revision: https://reviews.llvm.org/D47423
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@336963 91177308-0d34-0410-b5e6-96231b3b80d8
