Removed C test.
Code rebased on top of patch that enables mappings for modf/modff
(among others).

Teach LAA to consider safe specific math lib calls which are known to
have set the memory write-only attribute. Those attributes are set to
calls by inferNonMandatoryLibFuncAttrs, in BuildLibCalls.cpp, and the
current ones are modf/modff and frexp/frexpf.

This happens only when the calls are found through TLI to have
vectorized counterparts.

Functions like modf/modff are math lib calls that set memory write-only
attribute. Given that a target has vectorized mappings, LAA should allow
vectorization.

This is mostly NFC but some output does change due to consistently
inserting into poison rather than undef and using i64 as the index
type for inserts.

[LLVM][tests/Transforms/InstSimplify] Convert instances of ConstantExpr based splats to use splat().

This is mostly NFC but some output does change due to consistently
inserting into poison rather than undef and using i64 as the index
type for inserts.

This is mostly NFC but some output does change due to consistently
inserting into poison rather than undef and using i64 as the index
type for inserts.

This is mostly NFC but some output does change due to consistently
inserting into poison rather than undef and using i64 as the index
type for inserts.

This is mostly NFC but some output does change due to consistently
inserting into poison rather than undef and using i64 as the index
type for inserts.

To align TableGen consecutive definitions.

befa925a introduced preliminary hoisting of COPY
instructions when the user of the COPY is inside the same loop. That
optimization appeared to be too aggressive and hoisted too many COPY's
greatly increasing register pressure causing performance regressions for
AMDGPU target.

This is intended to fix the regression by hoisting COPY instruction only
if either:
 - User of COPY can be hoisted (other args are invariant) 
 or
 - Hoisting COPY doesn't bring high register pressure

Only test one example of each alias. Do not test error cases which are
already tested in the normal (non-alias) tests.

Note that the instructions have not been renamed and that there are no
corresponding aliases for ds_rsub_rtn_u32/u64. This matches SP3
behavior.

[AArch64][GlobalISel] Improve codegen for G_VECREDUCE_{SMIN,SMAX,UMIN,UMAX} for odd-sized vectors (#82740)

i8 vectors do not have their sizes changed as I noticed regressions in
some tests when that was done.

This patch also adds support for most G_VECREDUCE_* operations to
moreElementsVector in LegalizerHelper.cpp.

The code for getting the "neutral" element is taken almost exactly as it
is in SelectionDAG, with the exception that support for
G_VECREDUCE_{FMAXIMUM,FMINIMUM} was not added.

The code for SelectionDAG is located at
SelectionDAG::getNeutralELement().

Reverted due to some test failures on some buildbots.

https://lab.llvm.org/buildbot/#/builders/67/builds/14669

This reverts commit aa436493.

Fixes the prior issue in which the symbol for a cl-arg was unavailable to
some binaries.

This reverts commit dc06d75a.

This PR adds SPIR-V extension SPV_INTEL_variable_length_array that
allows to allocate local arrays whose number of elements is unknown at
compile time:
* add a new SPIR-V internal intrinsic:int_spv_alloca_array
* legalize G_STACKSAVE and G_STACKRESTORE
* implement allocation of arrays (previously getArraySize() of
AllocaInst was not used)
* add tests

This PR is to add support for the 'freeze' instruction:
https://llvm.org/docs/LangRef.html#freeze-instruction

There is no way to implement `freeze` correctly without support on
SPIR-V standard side, but we may at least address a simple (static) case
when undef/poison value presence is obvious. The main benefit of even
incomplete `freeze` support is preventing of translation from crashing
due to lack of support on legalization and instruction selection steps.

Support Fastmath flag to convert `complex.div` to standard dialects. 

See:
https://discourse.llvm.org/t/rfc-fastmath-flags-support-in-complex-dialect/71981

This removes a  CHECK-NOT: vector.body line from the test which seems to
imply the test does not get vectorized, but it does now.

This line was left over from when the test was pre-committed, remove it.

On a case insensitive file sytem, the build dir for `test_multiple_c` and
`test_multiple_C` are the same and therefore the log files are in the same
place. This means one tries to clear the log file for the other.

To fix this, make the names unique by adding the meaning of each
protocol packet.

https://sourceware.org/gdb/current/onlinedocs/gdb.html/Packets.html#Packets

I'm not aware of any remaining overrides of this function.

While I'm here, change an outdated comment in DataflowAnalysis.h that
still
referred to `merge()`. I've made the comment more general, referring
simply to
`ValueModel`, as we shouldn't really be repeating the documentation of
that
class here anyway.

https://gitlab.com/qemu-project/qemu/-/issues/1833 was fixed by
https://gitlab.com/qemu-project/qemu/-/commit/4b3520fd93cd49cc56dfcab45d90735cc2e35af7
which was included in v8.1.1.

The buildbot is now using v8.1.3 so the test is passing.

https://lab.llvm.org/buildbot/#/builders/179/builds/9468

This replaces `SmallVector<CondState>` and emulates it.

- -------- True  False DontCare
- Values:  True  False False
- Visited: True  True  False

`findIndependencePairs()` can be optimized with logical ops.

FIXME: Specialize `findIndependencePairs()` for the single word.

For instruction xvpermi.q, only [1:0] and [5:4] bits of operands[3] are
used. The unused bits in operands[3] need to be set to 0 to avoid
causing undefined behavior.

Codegen option is passed copy by value which 138 bytes of copy and used
as read-only. Making pass by const reference.

To reduce conditional judges in the loop in `findIndependencePairs()`, I
have tried a couple of tweaks.

* Isolate the final result in `TestVectors`

`using TestVectors = llvm::SmallVector<std::pair<TestVector,
CondState>>;`
The final result was just piggybacked on `TestVector`, so it has been
isolated.

* Filter out and sort `ExecVectors` by the final result

It will cost more in constructing `ExecVectors`, but it can reduce at
least one conditional judgement in the loop.

Otherwise modules.std-module.sh.cpp test fails with following error:
    error: no member named 'atomic_signed_lock_free' in namespace 'std'
when the types are not available.

This include 2 fixes:
        1. Disallow 'f' for softfloat.
        2. Allow 'r' for softfloat.

Currently, 'f' is accpeted by clang, then LLVM meets an internal error.

'r' is rejected by LLVM by: couldn't allocate input reg for constraint
'r'.

Fixes: #64241, #63632

---------

Co-authored-by: Fangrui Song <i@maskray.me>

llvm::dwarf::getDebugNamesBucketCount directly returns the bucket count,
via return statement, but it also returns the hash count via a
parameter. This changes the function to return them both as a std::pair,
in the return statement. It also changes the name of the function to
make it clear it returns both values.

This reverts commit 86f6caa5. Unit test
was failing on a few windows build bots