Changes

[X86][SSE] LowerVectorAllZero - add support for masked OR-reductions

If we're masking the result of an OR-reduction before comparing against zero, we can fold this into the PTEST() / MOVMSK(CMPEQ()) codegen by pre-masking the source value.

This works particularly well on PTEST which performs the AND as part of its operation, but the MOVMSK variant also benefits for non-V2I64 cases.

Fixes PR44781

[lldb/Test] Introduce "assertSuccess"

Summary:
A lot of our tests do 'self.assertTrue(error.Success()'. The problem
with that is that when this fails, it produces a completely useless
error message (False is not True) and the most important piece of
information -- the actual error message -- is completely hidden.

Sometimes we mitigate that by including the error message in the "msg"
argument, but this has two additional problems:
- as the msg argument is evaluated unconditionally, one needs to be
  careful to not trigger an exception when the operation was actually
  successful.
- it requires more typing, which means we often don't do it

assertSuccess solves these problems by taking the entire SBError object
as an argument. If the operation was unsuccessful, it can format a
reasonable error message itself. The function still accepts a "msg"
argument, which can include any additional context, but this context now
does not need to include the error message.

To demonstrate usage, I replace a number of existing assertTrue
assertions with the new function. As this process is not easily
automatable, I have just manually updated a representative sample. In
some cases, I did not update the code to use assertSuccess, but I went
for even higher-level assertion apis (runCmd, expect_expr), as these are
even shorter, and can produce even better failure messages.

Reviewers: teemperor, JDevlieghere

Subscribers: arphaman, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D82759

[ASTMatcher] Fix a performance regression: memorize the child match.

D80025 introduced a performance regression: in some cases, it makes
clang-tidy readability-container-size-empty ~80x slower (running on an internal
huge TU, before that patch 12s vs after 950s).

after this patch, we go back to 12s.

Differential Revision: https://reviews.llvm.org/D82771

[DWARFYAML][MachO] Remove endianness related tests.

fe08ab542bd6328a7906e38ae473cf655eb6a228 makes build bots unhappy
(http://lab.llvm.org:8011/builders/clang-s390x-linux/builds/33624/steps/ninja%20check%201/logs/FAIL%3A%20LLVM%3A%3ADWARF-debug_info.yaml).

This patch removes failed tests.

[libc++] Remove dead code since the removal of the old testing format

[runtimes] Rename newformat to just format, now that the old format has been removed

[AST][RecoveryExpr] Avoid spurious 'missing typename' diagnostic when the NNS contains errors.

Differential Revision: https://reviews.llvm.org/D82631

[SystemZ] Simplify knownbits.ll test

The knownbits.ll test case is somewhat fragile since:
- it relies on undef inputs; and
- it operates just at the limits of the MaxRecursionDepth

This means that optimization changes may easily cause the test
to spuriously fail.  Rewrite the test so it still validates
the same thing, but in a less fragile manner.

[NFC] Remove dead code

Differential Revision: https://reviews.llvm.org/D81195