If function return value's type is pointer, we can try to collect flat
address expression from it.
This PR also fixes noop_ptrint_pair_ce2 in noop-ptrint-pair.ll in #70611

C language standard defined library functions `iszero`, `issignaling`
and `issubnormal`, which did not have counterparts among clang builtin
functions. This change adds new functions:

    __builtin_iszero
    __builtin_issubnormal
    __builtin_issignaling

They provide builtin implementation for the missing standard functions.

Pull request: https://github.com/llvm/llvm-project/pull/69041

The discriminator can only pack 16 bits, so anything exceeding that
value will cause the packing code to crash. Emit a diagnostic and skip
the optimization instead.

The IR is valid, but UB: there is an out-of-bound index for the position
to insert inside the vector. We should just ignore this in the folder.

Fixes #70884

This make sure that an invalid negative dimension is ignored and stays
dynamic instead of crashing the compiler.

Fixes #70887

This PR exposes four APIs to C/OCaml bindings for `TargetMachine`:
```
/** Enable fast-path instruction selection. */
void LLVMSetTargetMachineFastISel(LLVMTargetMachineRef T, LLVMBool Enable);

/** Enable global instruction selection. */
void LLVMSetTargetMachineGlobalISel(LLVMTargetMachineRef T, LLVMBool Enable);

/** Set abort behaviour when global instruction selection fails to lower/select
 * an instruction. */
void LLVMSetTargetMachineGlobalISelAbort(LLVMTargetMachineRef T,
                                         LLVMGlobalISelAbortMode Mode);

/** Enable the MachineOutliner pass. */
void LLVMSetTargetMachineMachineOutliner(LLVMTargetMachineRef T,
                                         LLVMBool Enable);
```

Fixes #70666.

This reverts commit 3c727a95 because it
introduced some test failures:

https://lab.llvm.org/buildbot/#/builders/68/builds/62638



```
********************
Failed Tests (5):
  lldb-api :: functionalities/postmortem/elf-core/TestLinuxCore.py
  lldb-api :: functionalities/postmortem/mach-core/TestMachCore.py
  lldb-api :: functionalities/postmortem/netbsd-core/TestNetBSDCore.py
  lldb-api :: functionalities/unwind/noreturn/module-end/TestNoReturnModuleEnd.py
  lldb-api :: tools/lldb-dap/coreFile/TestDAP_coreFile.py
```

Signed-off-by: Med Ismail Bennani <ismail@bennani.ma>

- Implement `SubsetOpInterface`, `SubsetExtractionOpInterface`,
`SubsetInsertionOpInterface` for `vector.transfer_read` and
`vector.transfer_write`.
- Move all tensor subset hoisting test cases from `Linalg` to
`loop-invariant-subset-hoisting.mlir`. (Removing 1 duplicate test case.)

The KernelEnvironment is for compile time information about a kernel. It
allows the compiler to feed information to the runtime. The
KernelLaunchEnvironment is for dynamic information *per* kernel launch.
It allows the rutime to feed information to the kernel that is not
shared with other invocations of the kernel. The first use case is to
replace the globals that synchronize teams reductions with per-launch
versions. This allows concurrent teams reductions. More uses cases will
follow, e.g., per launch memory pools.

Fixes: https://github.com/llvm/llvm-project/issues/70249

The majority of subset ops operate on hyperrectangular subsets. This
commit adds a new optional interface method
(`getAccessedHyperrectangularSlice`) that can be implemented by such
subset ops. If implemented, the other `operatesOn...` interface methods
of the `SubsetOpInterface` do not have to be implemented anymore.

The comparison logic for hyperrectangular subsets (is
disjoint/equivalent) is implemented with `ValueBoundsOpInterface`. This
makes the subset hoisting more powerful: simple cases where two
different SSA values always have the same runtime value can now be
supported.

Improve the bypass analysis for loop-like ops. Until now, loop-like ops
were treated like any other non-subset ops: they prevent hoisting of any
sort because the analysis does not know which parts of a tensor init
operand are accessed by the loop-like op. With this change, the analysis
can look into loop-like ops and analyze which subset they are operating
on.

This is achieved by calling add_mlir_interface.

The issue manifests as ArithOpsInterfaces.h.inc not being available when
a pass includes something like MemRef.h which includes Arith.h.

Tested with check-mlir.

Add a loop-invariant subset hoisting pass to `mlir/Interfaces`. This
pass hoist loop-invariant tensor subsets (subset extraction and subset
insertion ops) from loop-like ops. Extraction ops are moved before the
loop. Insertion ops are moved after the loop. The loop body operates on
newly added region iter_args (one per extraction-insertion pair).

This new pass will be improved in subsequent commits (to support more
cases/ops) and will eventually replace
`Linalg/Transforms/SubsetHoisting.cpp`. In contrast to the existing
Linalg subset hoisting, the new pass is op interface-based
(`SubsetOpInterface` and `LoopLikeOpInterface`).

There is currently an op interface for subset insertion ops
(`SubsetInsertionOpInterface`), but not for subset extraction ops. This
commit adds `SubsetExtractionOpInterface` to `mlir/Interfaces`, as well
as a common dependent op interface: `SubsetOpInterface`.

- `SubsetOpInterface` is for ops that operate on tensor subsets. It
provides interface methods to check if two subset ops operate on
equivalent or disjoint subsets. Ops that implement this interface must
implement either `SubsetExtractionOpInterface` or
`SubsetInsertionOpInterface`.
- `SubsetExtractionOpInterface` is for ops that extract from a tensor at
a subset. E.g., `tensor.extract_slice`, `tensor.gather`,
`vector.transfer_read`. Current implemented only on
`tensor.extract_slice`.
- `SubsetInsertionOpInterface` is for ops that insert into a destination
tensor at a subset. E.g., `tensor.insert_slice`,
`tensor.parallel_insert_slice`, `tensor.scatter`,
`vector.transfer_write`. Currently only implemented on
`tensor.insert_slice`, `tensor.parallel_insert_slice`.

Other changes:
- Rename `SubsetInsertionOpInterface.td` to `SubsetOpInterface.td`.
- Add helper functions to `ValueBoundsOpInterface.cpp` for checking
whether two slices are disjoint.

The new interfaces will be utilized by a new "loop-invariant subset
hoisting"
transformation. (This new transform is roughly
what `Linalg/Transforms/SubsetHoisting.cpp` is doing, but in a generic
and interface-driven way.)

[Flang][OpenMP] Correctly handling continuation lines with Fixed Source Form Conditional Compilation Sentinels (#70309)

Fixes #67947

---------

Co-authored-by: SiHuaN <liyongtai@iscas.ac.cn>
Co-authored-by: Leandro Lupori <leandro.lupori@gmail.com>

This PR fixes the `I32ElementsAttr` and `I64ElementsAttr` builders and
tests them through the `python_test` dialect.

Most of the FP constants supported by FLI are positive. For negative FP
constants X whose positive values is supported by FLI, we can use `(FNEG
(FLI -X))` to materialize X.

No ownership is assumed for memref results of ops that implement none of
the relevant interfaces and have no memref operands. This fixes #68948.

These tests do not need to be updated when making changes to the API.

Optimize metadata query code:
- Avoid `DenseMap::operator[]` in situations where it is known that the
key exists in the map. Instead use `DenseMap::at()`/
`DenseMap::find()->second`. This avoids code-bloat and bad inlining
decisions for the unused insertion/growing code in `operator[]`.
- Avoid a redundant `Value::hasMetadata()` check.
- Move the `KindID == LLVMContext::MD_dbg` case to
`Instruction::getMetadata` and check it first assuming that it can be
constant folded after inlining in many situations.

The motivation for this change is a regression triggered by
e3cf80c5 which could attributed to the
compiler inlining the insertion part of `DenseMap::operator[]` in more
cases while unbeknownst to a compiler (without PGO) that code is never
used in this context. This change improves performance and eliminates
difference before and after that change in my measurements.

Expose loop results, which correspond to the region iter_arg values that
are returned from the loop when there are no more iterations. Exposing
loop results is optional because some loops (e.g., `scf.while`) do not
have a 1-to-1 mapping between region iter_args and op results.

Also add additional helper functions to query tied
results/iter_args/inits.

Rather than extending sparsifier codegen with higher order
non-permutations, we follow the path of rewriting linalg generic ops
into higher order operations. That way, code generation will simply work
out of the box. This is a very first proof-of-concept rewriting of that
idea.

Remove outdated content.
Suggested by @dcaballe in
https://github.com/llvm/llvm-project/pull/70673.

As an extension, accept the redundant use of the CONTIGUOUS attribute
when applied to scalars and to simply contiguous objects, with a
portability warning.

This patch fixes:

  mlir/test/lib/IR/TestBytecodeRoundtrip.cpp:403:10: error: unused
  variable 'status' [-Werror,-Wunused-variable]

After changes to <expected>, more test files are now properly formatted.

This change is for AArch32 and not strictly needed, but it ensures that
we follow the model that direct accesses are only emitted for dso_local
and we do not need TargetMachine::shouldAssumeDSOLocal to force
dso_local for a dso_preemptable variable.

There is no behavior change to the arm/arm64 configurations listed in
commit 5888dee7.

When emitting bytecode, clients can specify a target dialect version to
emit in `BytecodeWriterConfig`. This exposes a target dialect version to
the DialectBytecodeWriter, which can be queried by name and used to
back-deploy attributes, types, and properties.

The ELF code from https://reviews.llvm.org/D112811 emits LDRLIT_ga_pcrel
when `TM.isPositionIndependent()` but uses a different condition
`Subtarget.isGVIndirectSymbol(GV)` (aka dso_preemptable on ELF targets).
This would cause incorrect access for dso_preemptable
`__stack_chk_guard` with the static relocation model.

Regarding whether `__stack_chk_guard` gets the dso_local specifier,
https://reviews.llvm.org/D150841 switched to
`M.getDirectAccessExternalData()` (implied by "PIC Level") instead of
`TM.getRelocationModel() == Reloc::Static`.

The result is that when non-zero "PIC Level" is used with static
relocation model (e.g. -fPIE/-fPIC LTO compiles with -no-pie linking),
`__stack_chk_guard` accesses are incorrect.
```
        ldr     r0, .LCPI0_0
        ldr     r0, [r0]
        ldr     r0, [r0]   // incorrectly dereferences __stack_chk_guard
...
.LCPI0_0:
        .long   __stack_chk_guard
```

To fix this, for dso_preemptable `__stack_chk_guard`, emit a GOT PIC
code sequence like for -fpic using `LDRLIT_ga_pcrel`:
```
        ldr     r0, .LCPI0_0
.LPC0_0:
        add     r0, pc, r0
        ldr     r0, [r0]
        ldr     r0, [r0]
...
LCPI0_0:
.Ltmp0:
        .long   __stack_chk_guard(GOT_PREL)-((.LPC0_0+8)-.Ltmp0)
```

Technically, `LDRLIT_ga_abs` with `R_ARM_GOT_ABS` could be used, but
`R_ARM_GOT_ABS` does not have GNU or integrated assembler support.
(Note, `.LCPI0_0: .long __stack_chk_guard@GOT` produces an
`R_ARM_GOT_BREL`, which is not desired).

This patch fixes #6499 while not changing behavior for the following
configurations:
```
run arm.linux.nopic --target=arm-linux-gnueabi -fno-pic
run arm.linux.pie --target=arm-linux-gnueabi -fpie
run arm.linux.pic --target=arm-linux-gnueabi -fpic
run armv6.darwin.nopic --target=armv6-apple-darwin -fno-pic
run armv6.darwin.dynamicnopic --target=armv6-apple-darwin -mdynamic-no-pic
run armv6.darwin.pic --target=armv6-apple-darwin -fpic
run armv7.darwin.nopic --target=armv7-apple-darwin -mcpu=cortex-a8 -fno-pic
run armv7.darwin.dynamicnopic --target=armv7-apple-darwin -mcpu=cortex-a8 -mdynamic-no-pic
run armv7.darwin.pic --target=armv7-apple-darwin -mcpu=cortex-a8 -fpic
run arm64.darwin.pic --target=arm64-apple-darwin
```

In the rare case that an Xcode installation is damaged, this output
could contain clues to further diagnose the issue.

rdar://117698630

llvm/test/LTO/ARM/ssp-static-reloc.ll is more about using the static
relocation model with "PIC Level" and unrelated to the LTO infrastructure.
Move the test. Update stack_guard_remat.ll to clearly test "PIC Level"
with the relevant relocation models.