issue #55758

Note, this is a re-submission of D125894 with `features = ["-header_modules"]`
added to the main BUILD.bazel file.

Some functions like `stpncpy` are implemented in terms of `memset` but are not
currently using `-fno-builtin-memset`. This is somewhat hidden by the fact that
we use `-ffreestanding` globally and that `-ffreestanding` implies
`-fno-builtin` for Clang.

This patch also removes `-mllvm -combiner-global-alias-analysis` that is Clang
specific and that does not bring substantial gains on modern processors.

Also we keep `-mllvm --tail-merge-threshold=0` for aarch64 in CMakeLists.txt
but we omit it in the Bazel config. This is because Bazel consumes the source
files directly and so it can use PGO to take optimal decisions locally.

Differential Revision: https://reviews.llvm.org/D126773

For https://github.com/llvm/llvm-project/commit/7d76d6095880f34914d85d876b260cc4a4ea640d

This reverts commit 5890b301 as per discussion
on the review thread: https://reviews.llvm.org/D114487#3547560.

I'm a bit confused by what's actually stored for the allocation
hints. The MIR parser only handles the "simple" case where there's a
single hint. I don't really understand the assertion in
clearSimpleHint, or under what circumstances there are multiple hint
registers.

The constructor is not used. Remove it.

This reverts commit ec4adf1f. The commit causes
clang to hang on a certain input:
```
$ cat q.cc
int f(int a, int b) {
  int c = ((unsigned char)(a >> 23) & 925);
  if (a)
    c = (a >> 23 & b) | ((unsigned char)(a >> 23) & 925) | (b >> 23 & 157);
  return c;
}

$ time ./clang-15-10515 --target=x86_64--linux-gnu -O1  -c q.cc
^C

real    0m45.072s
user    0m0.025s
sys     0m0.099s
```

The basic infinite loop is lowered to a branch to the body of the
loop, and the body containing a back edge as its terminator.

Note: This is part of upstreaming from the fir-dev branch of
https://github.com/flang-compiler/f18-llvm-project.

Reviewed By: rovka

Differential Revision: https://reviews.llvm.org/D126697



Co-authored-by: Eric Schweitz <eschweitz@nvidia.com>
Co-authored-by: V Donaldson <vdonaldson@nvidia.com>

Add the cxx.bnf file as a dependency of custom gen commands, so that the
inc files can be rebuilt when cxx.bnf changes.

It doesn't look like we have test coverage for this at the moment :(

Avoid a behavior change when opaque pointers are enabled by default.

The FunctionTypeExtraBitfields is currently only available when the
ExceptionSpecificationType == Dynamic, which means that there is no other
way to use or extend the FunctionTypeExtraBitfields independently of the
exception specification type.

This patch adds a new field HasExtraBitfields to specify
whether the prototype has trailing ExtraBitfields.

This patch intends to be NFC and is required for future extension
and use of the ExtraBitfields struct.

Reviewed By: aaron.ballman, erichkeane

Differential Revision: https://reviews.llvm.org/D126642

Reviewed By: tpopp

Differential Revision: https://reviews.llvm.org/D126765

If the LHS/RHS selection operands can be cheaply concatenated back together then replace 2 x 128-bit selection nodes with 1 x 256-bit node

Addresses the regression introduced in the bug fix from rGd5af6a38

This patch updates the VPlan native path to use VPRegionBlocks for all
loops in a loop nest. Up to now, only the outermost loop used a region.

This is a step towards unifying both paths and keep things consistent
between them. It also prepares various code-gen parts for modeling the
pre-header in the inner loop vectorizer (D121624).

Reviewed By: Ayal

Differential Revision: https://reviews.llvm.org/D123005

Differential Revision: https://reviews.llvm.org/D126703

This revision adds `scf.foreach_thread` and other supporting abstractions
that allow connecting parallel abstractions and tensors.

Discussion is available [here](https://discourse.llvm.org/t/rfc-parallel-abstraction-for-tensors-and-buffers/62607).

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D126555

Lowering complex.tanh to standard dialects including math, arith.

Reviewed By: pifon2a

Differential Revision: https://reviews.llvm.org/D126521

This patch is a subpart of D125768 intented to make the review easier.

The `Address` struct represents a pointer but also adds compile time knowledge
like alignment or temporal/non-temporal that helps with downstream instruction
selection.

Differential Revision: https://reviews.llvm.org/D125966

This reverts commit 9b7193f8.

This is an older branch that was committed by mistake and does not include addressed review comments, an updated version will come next.

This revision adds `scf.foreach_thread` and other supporting abstractions
that allow connecting parallel abstractions and tensors.

Discussion is available [here](https://discourse.llvm.org/t/rfc-parallel-abstraction-for-tensors-and-buffers/62607).

Compiler-rt doesn't provide support file for cfi on s390x ad ppc64le (at least).
When trying to use the flag, we get a file error.

This is an attempt at making the error more explicit.

Differential Revision: https://reviews.llvm.org/D120484

This patch makes sure that `flang` (symlink to `flang-to-external-fc`)
is installed alongside other Flang tools. Fixes build failures in
clang-aarch64-full-2stage [1] introduced after merging
https://reviews.llvm.org/D125832.

[1] https://lab.llvm.org/buildbot/#/builders/179/builds/3799

Differential Revision: https://reviews.llvm.org/D126760

Now that SimpleLoopUnswitch and other transforms no longer introduce
branch on poison, enable the -branch-on-poison-as-ub option by
default. The practical impact of this is mostly better flag
preservation in SCEV, and some freeze instructions no longer being
necessary.

Differential Revision: https://reviews.llvm.org/D125299

The machine hosting these agents will be down
for maintenance June 2nd.

We (Linaro) will remove this once the agents are back online.

Differential Revision: https://reviews.llvm.org/D126688

The implementations of VPlanDominatorTree, VPlanLoopInfo and VPlanPredicator
are all incompatible with modeling loops in VPlans as region without
explicit back-edges.

Those pieces are not actively used and only exercised by a few gtest
unit tests. They are at the moment blocking progress towards unifying
the native and inner-loop vectorizer paths in D121624 and D123005.

I think we should not block forward progress on unused pieces of code,
so this patch removes the utilities for now. The plan is to re-introduce
them as needed in a way that is compatible with the unified VPlan scheme
used in both the inner loop vectorizer and the native path.

Reviewed By: sguggill

Differential Revision: https://reviews.llvm.org/D123017

Paths that start with `\\?\` are absolute paths, and aren't expected
to be used with wildcard expressions.

Previously, the `?` at the start of the path triggered the condition
for a potential wildcard, which caused the path to be split and
reassembled. In builds with `LLVM_WINDOWS_PREFER_FORWARD_SLASH=ON`,
this caused a path like e.g. `\\?\D:\tmp\hello.cpp` to be reassembled
into `\\?\D:\tmp/hello.cpp` which isn't a valid path (as such
absolute paths must use backslashes consistently).

This fixes https://github.com/mstorsjo/llvm-mingw/issues/280.

I'm not sure if there's any straightforward way to add a test
for this case, unfortunately.

Differential Revision: https://reviews.llvm.org/D126675

It's a fairly common issue that the generating code incorrectly marks
instructions as narrow or wide; check that the instruction lengths
add up to the expected value, and error out if it doesn't. This allows
catching code generation bugs.

Also check that prologs and epilogs are properly terminated, to
catch other code generation issues.

Differential Revision: https://reviews.llvm.org/D125647

Use the packed unwind info format if possible; otherwise try to
create a packed epilog.

Differential Revision: https://reviews.llvm.org/D125646

This includes .seh_* directives for generating it from assembly.
It is designed fairly similarly to the ARM64 handling.

For .seh_handler directives, such as
".seh_handler __C_specific_handler, @except" (which is supported
on x86_64 and aarch64 so far), the "@except" bit doesn't work in
ARM assembly, as '@' is used as a comment character (on all current
platforms).

Allow using '%' instead of '@' for this purpose. This convention
is used by GAS in similar contexts already,
e.g. [1]:

    Note on targets where the @ character is the start of a comment
    (eg ARM) then another character is used instead. For example the
    ARM port uses the % character.

In practice, this unfortunately means that all such .seh_handler
directives will need ifdefs for ARM.

Contrary to ARM64, on ARM, it's quite common that we can't evaluate
e.g. the function length at this point, due to instructions whose
length is finalized later. (Also, inline jump tables end with
a ".p2align 1".)

If unable to to evaluate the function length immediately, emit
it as an MCExpr instead. If we'd implement splitting the unwind
info for a function (which isn't implemented for ARM64 yet either),
we wouldn't know whether we need to split it though.

Avoid calling getFrameIndexOffset() on an unset
FuncInfo.UnwindHelpFrameIdx, to avoid triggering asserts in the
preexisting testcase CodeGen/ARM/Windows/wineh-basic.ll. (Once
MSVC exception handling is fully implemented, those changes
can be reverted.)

[1] https://sourceware.org/binutils/docs/as/Section.html#Section

Differential Revision: https://reviews.llvm.org/D125645

For ARM SEH, the epilogs will need a little more associated data than
just the plain list of opcodes.

This is a preparatory refactoring for D125645.

Differential Revision: https://reviews.llvm.org/D125879

Upstream the code for handling loops with real control variables from
the fir-dev branch at
https://github.com/flang-compiler/f18-llvm-project/tree/fir-dev/



Also add a test.

Loops with real-valued control variables are always lowered to
unstructured loops. The real-valued control variables are handled the
same as integer ones, the only difference is that they need to use
floating point instructions instead of the integer equivalents.

Co-authored-by: V Donaldson <vdonaldson@nvidia.com>

Reviewed By: martong

Differential Revision: https://reviews.llvm.org/D125986