[DAG] isSplatValue - node is a splat if all demanded elts have the same whole constant value (#74443)

`nsw` is a flag for LLVM arithmetic operations meaning "no signed wrap".
If this keyword is present, the result of the operation is a poison
value if overflow occurs. Adding this keyword permits LLVM to re-order
integer arithmetic more aggressively.

In

https://discourse.llvm.org/t/rfc-changes-to-fircg-xarray-coor-codegen-to-allow-better-hoisting/75257/16
@vzakhari observed that adding nsw is useful to enable hoisting of
address calculations after some loops (or is at least a step in that
direction).

Classic flang also adds nsw to address calculations.

Update VPWidenCastRecipe to also print flags. Simplify nneg printing
test and replace hard-coded value number references with patterns.

This reverts commit e33302fa.

there is a fix already, sorry for the noise

This reverts commit 11a7e578.

Test fails: https://lab.llvm.org/buildbot/#/builders/219/builds/7416 and
others.

To simplify some code.

[X86] LowerBUILD_VECTOR - don't use insert_element(constant, elt, idx) if we have a freeze(undef) element

Fixes #74736

Treat a defined register as fully live "at" the instruction and update maximum pressure accordingly. Fixes #3786.

We have a bunch of folds that basically perform X pred Y to ~Y pred ~X
for various special cases where this saves an instruction.

Generalize these folds to use isFreeToInvert(). We have to make sure
that we consume an instruction in either of the inversions, otherwise
we're just going to swap the icmp back and forth.

Fixes https://github.com/llvm/llvm-project/issues/74302.

If we have vectorized variants of a function which take linear
parameters, we should be able to vectorize assuming the strides match.

The `expect_expr` check was introduced in
https://github.com/llvm/llvm-project/pull/74772. It is failing on Linux
and Windows, so skip this test to unblock the bots

opt accepts the -march command-line argument, but this argument only
makes sense in conjunction with -mtriple. Fix a couple of tests under
LoopVectorize that invoke opt with -march but without -mtriple, to avoid
confusing users.

The first couple of llc invocations mentioned in the document are wrong,
and users will get confused about no output being written. Fix them.

Declare `getPreservedProducerResults` function which helps to get the
preserved results of the producer linalg generic operation as a result
of elementwise fusion.

Reverts llvm/llvm-project#72713

Buildbot tests fail on clang-armv7-global-isel builder
https://lab.llvm.org/buildbot/#/builders/186/builds/13604

This MR fix the argument name of GEPOp builder from `basePtrType` to
`elementType` to avoid confusion.

Co-authored-by: Xiaolei Shi <xiaoleis@nvidia.com>

This patch continues the work started with ea5b1ef0. See that commit and its
corresponding PR for details.

This patch does the following simplifications:
```
cttz(shl(C, X), 1) -> add(cttz(C, 1), X)
cttz(lshr exact(C, X), 1) -> sub(cttz(C, 1), X)
ctlz(lshr(C, X), 1) --> add(ctlz(C, 1), X)
ctlz(shl nuw (C, X), 1) --> sub(ctlz(C, 1), X)
```
Alive2: https://alive2.llvm.org/ce/z/9KHlKc
Closes #41333

This patch adds llvm-readobj support for:

- Dynamic R_AARCH64_AUTH_* relocations (including RELR compressed AUTH
relocations) as described here:
https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#auth-variant-dynamic-relocations

- .note.AARCH64-PAUTH-ABI-tag section as defined here
https://github.com/ARM-software/abi-aa/blob/main/pauthabielf64/pauthabielf64.rst#elf-marking

And add some patterns:
1. (fdiv 1.0, vector)
2. (fdiv 1.0, (fsqrt vector))

Apply clang-tidy fixes for llvm-prefer-isa-or-dyn-cast-in-conditionals in MapMemRefStorageClassPass.cpp (NFC)

[mlir][Transforms][NFC] GreedyPatternRewriteDriver: Remove redundant worklist management code (#74796)

Do not add the previous users of replaced ops to the worklist during
`notifyOperationReplaced`.

The previous users are modified inplace as part of
`PatternRewriter::replaceOp`, which calls
`PatternRewriter::replaceAllUsesWith`. The latter function updates all
users with `updateRootInPlace`, which already puts all previous users of
the replaced op on the worklist. No further worklist management work is
needed in the `notifyOperationReplaced` callback.

Identified with clangd.

Fix test initialization

This reverts commit d4136813.

Fix test array initialization.

When `sym` in `.reloc ., BFD_RELOC_NONE, sym` is not referenced
elsewhere, `sym` is not in the symbol table and the relocation
references the null symbol. Visit the expression to fix the issue.

Remove redundant initializations from pass constructors that were
already being initialized by LLVMInitializeRISCVTarget().