Changes

[X86][AVX] Pad small shuffle inputs in combineX86ShufflesRecursively

As detailed on PR45974 and D79987, getFauxShuffleMask is creating nodes on the fly to create shuffles with inputs the same size as the result, causing problems for hasOneUse() checks in later simplification stages.

Currently only combineX86ShufflesRecursively benefits from these widened inputs so I've begun moving the functionality there, and out of getFauxShuffleMask. This allows us to remove the widening from VBROADCAST and *EXTEND* faux shuffle cases.

This just leaves the INSERT_SUBVECTOR case in getFauxShuffleMask still creating nodes, which will require more extensive refactoring.

[X86][AVX] getFauxShuffleMask - don't widen shuffle inputs from INSERT_SUBVECTOR(X,SHUFFLE(Y,Z))

Don't create nodes on the fly when decoding INSERT_SUBVECTOR as faux shuffles.

[PhaseOrdering] add scalarization test for PR42174; NFC

Motivating test for vector-combine enhancement in D80885.
Make sure that vectorization and canonicalization are
working together as expected.

[X86][AVX] Add test case described in D79987

[X86] getFauxShuffleMask/getTargetShuffleInputs - make SelectionDAG const (PR45974).

Try to prevent future node creation issues (as detailed in PR45974) by making the SelectionDAG reference const, so it can still be used for analysis, but not node creation.

[VectorCombine] add tests for scalarizing binop-with-constant; NFC

Goes with proposal in D80885.

This is adapted from the InstCombine tests that were added for
D50992

But these should be adjusted further to provide more interesting
scenarios for x86-specific codegen. Eg, vector types/sizes will
have different costs depending on ISA attributes.

We also need to add tests that include a load of the scalar
variable and add tests that include extra uses of the insert
to further exercise the cost model.

[X86][AVX] Add SimplifyMultipleUseDemandedBits VBROADCAST handling to SimplifyDemandedVectorElts.

As suggested on D79987.

[PhaseOrdering] add test for hoisting/CSE (PR46115); NFC

[utils] change update_test_checks.py use of 'TMP' value names

As discussed in PR45951:
https://bugs.llvm.org/show_bug.cgi?id=45951

There's a potential name collision between update_test_checks.py and -instnamer
and/or manually-generated IR test files because all of them try to use the
variable name that should never be used: "tmp".

This patch proposes to reduce the odds of collision and adds a warning if we
detect the problem. This will cause regression test churn when regenerating
CHECK lines on existing files.

Differential Revision: https://reviews.llvm.org/D80584

AArch64/GlobalISel: Fix incorrect ptrmask usage for alignment

I inverted the mask when I ported to the new form of G_PTRMASK in
8bc03d2168241f7b12265e9cd7e4eb7655709f34.

I don't think this really broke anything, since G_VASTART isn't
handled for types with an alignment higher than the stack alignment.

clang-tidy and clang-query wont crash with invalid command line options

Summary: Motivated by [[ https://bugs.llvm.org/show_bug.cgi?id=46141 | clang-tidy crashed for unknown command line argument. ]]

Reviewers: aaron.ballman, alexfh

Reviewed By: aaron.ballman

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D80879

[utils] update expected strings in tests; NFC

The script was changes with:
https://github.com/llvm/llvm-project/commit/bfdc2552664d6f0bb332a9c6a115877020f3c1df

Revert "clang-tidy and clang-query wont crash with invalid command line options"

This reverts commit f23ddbe3c3ae5f40b99ba272afc3d16b800ba8b9.

clang-tidy and clang-query wont crash with invalid command line options

Motivated by [[ https://bugs.llvm.org/show_bug.cgi?id=46141 | clang-tidy crashed for unknown command line argument. ]]

Reviewed By: aaron.ballman, thakis

Differential Revision: https://reviews.llvm.org/D80879

Change some extraneous /// comments to // comments inside methods. NFC.

[X86][AVX] combineX86ShufflesRecursively - peekThroughOneUseBitcasts subvector before widening.

This matches what we do for the full sized vector ops at the start of combineX86ShufflesRecursively, and helps getFauxShuffleMask extract more INSERT_SUBVECTOR patterns.

[X86][AVX] Reduce unary target shuffles width if the upper elements aren't demanded.

[X86] Rewrite how X86PartialReduction finds candidates to consider optimizing.

Previously we walked the users of any vector binop looking for
more binops with the same opcode or phis that eventually ended up
in a reduction. While this is simple it also means visiting the
same nodes many times since we'll do a forward walk for each
BinaryOperator in the chain. It was also far more general than what
we have tests for or expect to see.

This patch replaces the algorithm with a new method that starts at
extract elements looking for a horizontal reduction. Once we find
a reduction we walk through backwards through phis and adds to
collect leaves that we can consider for rewriting.

We only consider single use adds and phis. Except for a special
case if the Add is used by a phi that forms a loop back to the
Add. Including other single use Adds to support unrolled loops.

Ultimately, I want to narrow the Adds, Phis, and final reduction
based on the partial reduction we're doing. I still haven't
figured out exactly what that looks like yet. But restricting
the types of graphs we expect to handle seemed like a good first
step. As does having all the leaves and the reduction at once.

Differential Revision: https://reviews.llvm.org/D79971

[test][compiler-rt] Avoid LD_PRELOAD for "outer" dynamic linkers

Summary:
This patch moves the setting of `LD_PRELOAD` "inwards" to avoid issues
where the built library needs to be loaded with the dynamic linker that
was configured with the build (and cannot, for example, be loaded by the
dynamic linker associated with the `env` utility).

Reviewed By: vitalybuka, nemanjai, jsji

Differential Revision: https://reviews.llvm.org/D79695

[Driver] NFC: Use Twine temp to replace std::string local

This patch replaces a `std::string` local used for a concatentation with
a `Twine` where the string was being passed into call.

[analyzer] Add dumps to CheckerRegistry

[Driver] Simplify Linux::addProfileRTLibs

AMDGPU/GlobalISel: Add stub reg-bank aware combiner pass

[gn build] (semi-manually) port a8ca0ec2670

[PowerPC] Exploit vabsd on P9

Summary: Exploit vabsd* for for absolute difference of vectors on P9,
for example:
void foo (char *restrict p, char *restrict q, char *restrict t)
{
  for (int i = 0; i < 16; i++)
     t[i] = abs (p[i] - q[i]);
}
this case should be matched to the HW instruction vabsdub.

Reviewed By: steven.zhang

Differential Revision: https://reviews.llvm.org/D80271