For each natural loop with multiple exit blocks, this pass creates a
new block N such that all exiting blocks now branch to N, and then
control flow is redistributed to all the original exit blocks.

The bulk of the tranformation is a new function introduced in
BasicBlockUtils that an redirect control flow from a set of incoming
blocks to a set of outgoing blocks via a common "hub".

This is a useful workaround for a limitation in the structurizer which
incorrectly orders blocks when processing a nest of loops. This pass
bypasses that issue by ensuring that each natural loop is recognized
as a separate region. Since the structurizer is a region pass, it no
longer sees a nest of loops in a single region, and instead processes
each "level" in the nesting as a separate region.

The AMDGPU backend provides a new option to enable this pass before
the structurizer, which may eventually be enabled by default.

Reviewers: madhur13490, arsenm, nhaehnle

Reviewed By: nhaehnle

Differential Revision: https://reviews.llvm.org/D75865

In InnerLoopVectorizer::getOrCreateTripCount, when the backedge taken
count is a SCEV add expression, its type is defined by the type of the
last operand of the add expression.

In the test case from PR45259, this last operand happens to be a
pointer, which (according to llvm::Type) does not have a primitive size
in bits. In this case, LoopVectorize fails to truncate the SCEV and
crashes as a result.

Uing ScalarEvolution::getTypeSizeInBits makes the truncation work as expected.

https://bugs.llvm.org/show_bug.cgi?id=45259

Differential Revision: https://reviews.llvm.org/D76669

Currently, `error: incompatible section flags for .rodata` is reported
when we mix SHF_LINK_ORDER and non-SHF_LINK_ORDER sections in an output section.

This is overconstrained. This patch allows mixed flags with the
requirement that SHF_LINK_ORDER sections must be contiguous. Mixing
flags is used by Linux aarch64 (https://github.com/ClangBuiltLinux/linux/issues/953)

  .init.data : { ... KEEP(*(__patchable_function_entries)) ... }

When the integrated assembler is enabled, clang's -fpatchable-function-entry=N[,M]
implementation sets the SHF_LINK_ORDER flag (D72215) to fix a number of
garbage collection issues.

Strictly speaking, the ELF specification does not require contiguous
SHF_LINK_ORDER sections but for many current uses of SHF_LINK_ORDER like
.ARM.exidx/__patchable_function_entries there has been a requirement for
the sections to be contiguous on top of the requirements of the ELF
specification.

This patch also imposes one restriction: SHF_LINK_ORDER sections cannot
be separated by a symbol assignment or a BYTE command. Not allowing BYTE
is a natural extension that a non-SHF_LINK_ORDER cannot be a separator.
Symbol assignments can delimiter the contents of SHF_LINK_ORDER
sections.  Allowing SHF_LINK_ORDER sections across symbol assignments
(especially __start_/__stop_) can make things hard to explain. The
restriction should not be a problem for practical use cases.

Reviewed By: psmith

Differential Revision: https://reviews.llvm.org/D77007

It's set to OFF by default at libcxx/CMakeLists.txt:73.

Differential Revision: https://reviews.llvm.org/D76905

This allows adding compilation flags for a single test, which can help
eliminate some .sh.cpp tests and some custom handling in the libc++
test format.

It also works around the issue that .sh.cpp substitutions are _not_
equivalent to the actual compiler command lines used to compile tests,
since the compiler flags can be modified in local lit configurations,
and substitutions are frozen at that point. For example using %{compile}
in a .sh.cpp test in the coroutines subdirectory will not include the
-fcoroutines-ts flag, which is added in the local lit config, because
the %{compile} substitution is created long before we add -fcoroutines-ts
to the compiler flags (in the lit.local.cfg for coroutines).

[X86] make sure POP has implicit def/use of stack pointer when materializing 8-bit immediates for minsize

Summary:
Otherwise PostRA list scheduler may reorder instruction, such as

schedule this
'''
pushq  $0x8
pop    %rbx
lea    0x2a0(%rsp),%r15
'''
to
'''
pushq  $0x8
lea    0x2a0(%rsp),%r15
pop    %rbx
'''
by mistake. The patch is to prevent this to happen by making sure POP has
implicit use of SP.

Reviewers: craig.topper

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77031

Reviewers: Szelethus, NoQ

Subscribers: whisperity, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, donat.nagy, dkrupp, gamesh411, Charusso, steakhal, ASDenysPetrov, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77061

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: jyknight, sdardis, nemanjai, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, jfb, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77059

This reverts commit because of test failures in TestHelloWorld.

It seems that this test (specifically running "ls" as a platform shell
command) depended on the implicit passing of the host environment.

The fix should be fairly simple (inherit the environment explicitly),
but it may take me a while to figure where exactly to do that. Revert
while I am figuring that out.

This will become more relevant as we shift more filesystem-specific
logic to the local lit configuration in test/std/input.output/filesystems.

I still think the call lowering type legalization logic split between
the generic code and target is too confusing, but largely induced by
the reliance on the DAG infrastructure.

Mostly ported from the DAG version. This results in much worse code
than the DAG version, largely due to a much worse expansion for
G_UMULH.

InstCombine does not result in an incorrect debuginfo variable
value

- Add an additional salvage and a test.

Reviewers: aprantl, djtodoro

Differential Revision: https://reviews.llvm.org/D76854

Bugzilla:  https://bugs.llvm.org/show_bug.cgi?id=44371

As per post-commit comment at https://reviews.llvm.org/D76916, this
should better be done at the TU level.

This reverts commit 9ce198d6.

Found by msan.

Summary:
A defensive check in ProcessLauncherWindows meant that we would never
attempt to launch a process with a completely empty environment -- the
host environment would be used instead. Instead, I make the function add
an extra null wchar_t at the end of an empty environment. The
documentation on this is a bit fuzzy, but it seems to be what is needed
to make windows accept these kinds of environments.

Reviewers: amccarth, friss

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D76835

Since its important to know whether a function frees memory (even if its a
reallocating function!), I used two CallDescriptionMaps to merge all
CallDescriptions into it. MemFunctionInfoTy no longer makes sense, it may never
have, but for now, it would be more of a distraction then anything else.

Differential Revision: https://reviews.llvm.org/D68165

Summary:
D73024 seems to have fixed one set crash, but it introduced another.
Namely, if a class contains a covariant method returning itself, the
logic in MaybeCompleteReturnType could cause us to attempt a recursive
import, which would result in an assertion failure in
clang::DeclContext::removeDecl.

For some reason, this only manifested itself if the class contained at
least two member variables, and the class itself was imported as a
result of a recursive covariant import.

This patch fixes the crash by not attempting to import classes which are
already completed in MaybeCompleteReturnType. However, it's not clear to
me if this is the right fix, or if this should be handled automatically
by functions lower in the stack.

Reviewers: teemperor, shafik

Subscribers: lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D76840

value as undefined

    - Correct a debug info salvage and add a test

    Reviewers: aprantl, vsk

    Differential Revision: https://reviews.llvm.org/D76930
    Bugzilla: https://bugs.llvm.org/show_bug.cgi?id=45080

We've been meaning to remove those targets for a while, and the fix is
simple enough cause they're all just aliases to other targets.

This is a re-application of f383fb40, wich was reverted in 04d48111
because the build bots had not been updated yet. The build bot configurations
have now been updated not to use the deprecated targets, and I verified
that they were using the non-deprecated targets, so we should be good
unless I missed a bot.

Differential Revision: https://reviews.llvm.org/D76104

Goes with D76983

Summary:
Added basic representation and parsing/sema handling of array-shaping
operations. Array shaping expression is an expression of form ([s0]..[sn])base,
where s0, ..., sn must be a positive integer, base - a pointer. This
expression is a kind of cast operation that converts pointer expression
into an array-like kind of expression.

Reviewers: rjmccall, rsmith, jdoerfert

Subscribers: guansong, arphaman, cfe-commits, caomhin, kkwli0

Tags: #clang

Differential Revision: https://reviews.llvm.org/D74144

[Alignment][NFC] Provide tightened up functions in SelectionDAG, MachineFunction and MachineMemOperand

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: hiraditya, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77046

Summary: We mark these decls as invalid.

Reviewers: sammccall

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77037

This test missed the check of histograms printed for .hash sections.
It was removed by mistake in D71606 where I tried to get rid of precompiled objects
and did not realize that time that both SHT_GNU_HASH and SHT_HASH sections
were tested and not just GNU version.

Also it never tested aliases for the --elf-hash-histogram option.

Differential revision: https://reviews.llvm.org/D76920

On Ubuntu, we want to raise default CLANG_SYSTEMZ_ARCH to z13,
thus allow configuring this via CMake.
On Debian, we want to raise it to z196.

Author: Dimitri John Ledkov
Differential Revision: https://reviews.llvm.org/D75914

LLDB only automatically applies Fix-Its from errors, but not from warnings.

Currently we only store Fix-Its from errors and then later apply all Fix-Its
we stored. This moves the filter to the application phase, so that we now
store *all* Fix-Its but only apply Fix-Its from errors later on.

This is NFC preparation for an upcoming patch.

Commit 83c81c0a enabled Fix-Its for top-level
expressions which change the error message of this test here as Clang comes
up with a strange Fix-It for this expression. This patch just changes the
test to declare a void variable so that Clang doesn't see a way to
recover with a Fix-It and change the error message.

We are able to reduce `-DBITS=32/64` to reduce this test case.
I've rewrote the comments we had to generalize them and
fix wrong computations they contained.

Differential revision: https://reviews.llvm.org/D76924

If we are lowering to X86ISD::SHUF128 we are going to lose track of individual 128-bit lanes that are UNDEF, so if we can widen these to guarantee that they are sequential with their neighbour we should. This helps with later shuffle combines.

Commit "[clang-format] Handle C# generic type constraints",
https://github.com/llvm/llvm-project/commit/dcbcec4822f47ec5b638dd9c20dcebd464569dae
regressed the formatting of code containing `where` as an identifier in other
languages.

The Chained in the name potentially leads to confusion. Also updated the
comment to drop the unnecessary mention of tile-sized.

This fixes

    warning: loop variable 'Def' of type 'const llvm::Register' creates a copy from type 'const llvm::Register' [-Wrange-loop-analysis]

llvm::Register just contains a single unsigned and should be copied.

Reviewers: rampitec

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D77011

Summary:
Currently top-level expressions won't automatically get Fix-Its applied. The reason
for that is that we only set the `m_fixed_text` member if we have a wrapping
source code (I.e. `m_source_code` is not zero and is wrapping some expressions).

This patch just always sets `m_fixed_text` to get this working.

Reviewers: labath, jingham

Reviewed By: labath

Subscribers: JDevlieghere

Differential Revision: https://reviews.llvm.org/D77042

Use script to update test for ori with 32-bit imms, and add test for
ori with 64-bit imms.