Changes

Update recipe for flang-aarch64 slaves

- Update compiler location for flang-aarch64-ubuntu-{clang and gcc10}
- Add another email to the extra recipient for flang-aarch64
- Make flang-aarch64 slaves build new flang driver by default
- Add a missing coma to flang-aarch64-ubuntu-gcc10 recipe

Differential Revision: https://reviews.llvm.org/D87125

clang-x86-ninja-win10 - replacing backslashes

in buildbot.tac with forward slashes to address re-configuration
cycles in cmake

[WebAssembly][MC] Fix computation of relative symbol offset

For relative symbols, add its offset when computing relocation value.
Also, warn on unsupported absolute symbols.

Differential Revision: https://reviews.llvm.org/D87407

Reorder linalg.conv indexing_maps loop order

Change the indexing map to iterate over the (b, x0, x1, z0, z1, q, k) instead of (b, x0, x1, k, q, z0, z1) to evaluate the convolution expression:
Y[b, x0, x1, k] = sum(W[z0, z1, q, k] * X[b, x0 + z0, x1 + z1, q], z0, z1, q)

This allows llvm auto vectorize to work and has better locality resulting significant performance improvments

Differential Revision: https://reviews.llvm.org/D87781

[AlwaysInliner] Emit optimization remarks

To match the normal inliner in preparation for https://reviews.llvm.org/D86988.

Also change a FIXME to an assert.

Reviewed By: davidxl

Differential Revision: https://reviews.llvm.org/D88067

[clangd] Link libclangdSupport into clangd-index-server

Fixes https://github.com/clangd/clangd/issues/534

Differential Revision: https://reviews.llvm.org/D87979

[clang] Traverse init-captures while indexing

Fixes https://github.com/clangd/clangd/issues/496

Differential Revision: https://reviews.llvm.org/D87257

[CMake] Use find_dependency in LLVMConfig.cmake

This prefered over find_package as find_dependency forwards the correct
parameters for QUIET and REQUIRED to find_package.

Differential Revision: https://reviews.llvm.org/D88069

[CMake] Use append for CMAKE_REQUIRED_* variables

This ensures that required includes and libraries such as -lm that
were added earlier aren't overwritten.

Differential Revision: https://reviews.llvm.org/D88068

[SyntaxTree][Nit] Take `ArrayRef` instead of `std::vector` as argument for `createTree`

I also assured that there are no other functions unnecessarily using std::vector as argument.

Differential Revision: https://reviews.llvm.org/D88024

[SyntaxTree] Test `findFirstLeaf` and `findLastLeaf`

* Introduce `TreeTest.cpp` to unit test `Tree.h`
* Add `generateAllTreesWithShape` to generating test cases
* Add tests for `findFirstLeaf` and `findLastLeaf`
* Fix implementations of `findFirstLeaf` and `findLastLeaf` that had
been broken when empty `Tree` were present.

Differential Revision: https://reviews.llvm.org/D87779

[gn build] Port af582c9b0f3

Revert "[CMake] Use find_dependency in LLVMConfig.cmake"

This reverts commit 247c4fc50720ed48db2464bbe59839eedbe16794 as it
broke the runtime build.

Reapply: [clang-cl] Always interpret the LIB env var as separated with semicolons

When cross compiling with clang-cl, clang splits the INCLUDE env
variable around semicolons (clang/lib/Driver/ToolChains/MSVC.cpp,
MSVCToolChain::AddClangSystemIncludeArgs) and lld splits the
LIB variable similarly (lld/COFF/Driver.cpp,
LinkerDriver::addLibSearchPaths). Therefore, the consensus for
cross compilation with clang-cl and lld-link seems to be to use
semicolons, despite path lists normally being separated by colons
on unix and EnvPathSeparator being set to that.

Therefore, handle the LIB variable similarly in Clang, when
handling lib file arguments when driving linking via Clang.

This fixes commands like "clang-cl test.c -Fetest.exe kernel32.lib" in
a cross compilation setting. Normally, most users call (lld-)link
directly, but meson happens to use this command syntax for
has_function() tests.

Reapply: Change Program.h to define procid_t as ::pid_t. When included
in lldb/unittests/Host/NativeProcessProtocolTest.cpp, it is included
after an lldb namespace containing an lldb::pid_t typedef, followed
later by a "using namespace lldb;". Previously, Program.h wasn't
included in this translation unit, but now it ends up included
transitively from Process.h.

Differential Revision: https://reviews.llvm.org/D88002

[AArch64] Fix return type of Neon scalar comparison intrinsics

The following should have unsigned return types
but were signed:
vceqd_s64 vceqzd_s64 vcged_s64 vcgezd_s64
vcgtd_s64 vcgtzd_s64 vcled_s64 vclezd_s64
vcltd_s64 vcltzd_s64 vtstd_s64

See https://developer.arm.com/documentation/ihi0073/latest

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D88009

[ARM] VPT validForTailPredication

Mark all VPT instructions as valid.

Differential Revision: https://reviews.llvm.org/D87759

[ARM] Remove MVEDomain from VLDR/STR of P0

Remove the domain from the instructions and create a shouldInspect
helper for LowOverheadLoops which queries it or a vpr operand.

Differential Revision: https://reviews.llvm.org/D87900

[MLIR] Add subf and rsqrt EDSC intrinsics

[MLIR] Add subf and rsqrt EDSC intrinsics

NOTE: Please merge it when ready.

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D88039

[mlir][Linalg] Uniformize linalg.generic with named ops.

This revision allows representing a reduction at the level of linalg on tensors for generic ops by uniformizing with the named ops approach.

[llvm-readobj/elf] - Stop reporting invalid extended indexes in warnings for unnamed section symbols.

We have an issue with `getFullSymbolName`: it assumes that the symbol passed is
always in the `.symtab`, what is wrong. We might calculate and report a wrong index currently.
I've added a test case revealing that.

This patch adds the "symbol index" argument to `getFullSymbolName` signature,
what fixes the issue.

Differential revision: https://reviews.llvm.org/D87899

[SyntaxTree][Synthesis] Fix: `deepCopy` -> `deepCopyExpandingMacros`.

There can be Macros that are tagged with `modifiable`. Thus verifying
`canModifyAllDescendants` is not sufficient to avoid macros when deep
copying.

We think the `TokenBuffer` could inform us whether a `Token` comes from
a macro. We'll look into that when we can surface this information
easily, for instance in unit tests for `ComputeReplacements`.

Differential Revision: https://reviews.llvm.org/D88034

Revert "Reapply Revert "RegAllocFast: Rewrite and improve""

This reverts commit 55f9f87da2c2ad791b9e62cccb1c035e037444fa.

Breaks following buildbots:
http://lab.llvm.org:8011/builders/lldb-arm-ubuntu/builds/4306
http://lab.llvm.org:8011/builders/lldb-aarch64-ubuntu/builds/9154

[ARM] Improve VPT predicate tracking

The VPTBlock has been modified to track the 'global' state of the
VPR, as well as the state for each block. Each object now just holds
a list of instructions that makeup the block, while static structures
hold the predicate information. This enables global access for
querying how both a VPT block and individual instructions are
predicated. These changes now allow us, again, to handle more
complicated cases where multiple instructions build a predicate
and/or where the same predicate in used in multiple blocks.

It doesn't, however, get us back to before the tracking was 'fixed'
as some extra logic will be required to properly handle VPT
instructions. Currently a VPT could be effectively predicated because
of it's inputs, but the existing logic will not detect that and so
will refuse to perform the transformation. This can be seen in
remat-vctp.ll test where we still don't perform the transform.

Differential Revision: https://reviews.llvm.org/D87681

[AMDGPU] More codegen patterns for v2i16/v2f16 build_vector

It's simpler to do this at codegen time than to do ad-hoc constant
folding of machine instructions in SIFoldOperands.

Differential Revision: https://reviews.llvm.org/D88028

Revert "Implement a new kind of Pass: dynamic pass pipeline"

This reverts commit 385c3f43fceba227be2e4dce84a59075733541c1.

Test  mlir/test/Pass:dynamic-pipeline-fail-on-parent.mlir.test fails
when run with ASAN:

ERROR: AddressSanitizer: stack-use-after-scope on address ...

Reviewed By: bkramer, pifon2a

Differential Revision: https://reviews.llvm.org/D88079

[SCEV] Support unsigned predicates in isKnownPredicateViaNoOverflow

SCEV should be able to prove facts like `x <u x+1<nuw>`.

Differential Revision: https://reviews.llvm.org/D88015
Reviewed By: lebedev.ri

[MLIR][Linalg] Fix assertion in dependency analysis

The assertion falsely expected ranked memrefs only.  Now both, ranked and
unranked memrefs are allowed.

Differential Revision: https://reviews.llvm.org/D88080

[NFC][PowerPC]Add tests for multiply-by-constant.

[APFloat] multiplySignificand - always pass IEEEFloat as const reference. NFCI.

We do this in all other cases.

[PowerPC] Add support for R_PPC64_GOT_TPREL_PCREL34 used in TLS Initial Exec

Add Thread Local Storage Initial Exec support to LLD.

This patch adds the computation for the relocations as well as the relaxation from Initial Exec to Local Exec.

Initial Exec:
```
pld r9, x@got@tprel@pcrel
add r9, r9, x@tls@pcrel
```
or
```
pld r9, x@got@tprel@pcrel
lbzx r10, r9, x@tls@pcrel
```
Note that @tls@pcrel is actually encoded as R_PPC64_TLS with a one byte displacement.

For the above examples relaxing Intitial Exec to Local Exec:
```
paddi r9, r9, x@tprel
nop
```
or
```
paddi r9, r13, x@tprel
lbz r10, 0(r9)
```

Reviewed By: nemanjai, MaskRay, #powerpc

Differential Revision: https://reviews.llvm.org/D86893

Revert rGf835779160ec303 "[APFloat] multiplySignificand - always pass IEEEFloat as const reference. NFCI."

This reverts commit f835779160ec30340676918915526615a07e826e while I investigate some buildbot failures

[lldb] Ignore certain Clang type sugar when creating the type name

Clang has some type sugar that only serves as a way to preserve the way a user
has typed a certain type in the source code. These types are currently not
unwrapped when we query the type name for a Clang type, which means that this
type sugar actually influences what formatters are picked for a certain type.
Currently if a user decides to reference a type by doing `::GlobalDecl Var = 3;`,
the type formatter for `GlobalDecl` will not be used (as the type sugar
around the type gives it the name `::GlobalDecl`. The same goes for other ways
to spell out a type such as `auto` etc.

With this patch most of this type sugar gets stripped when the full type name is
calculated. Typedefs are not getting desugared as that seems counterproductive.
I also don't desugar atomic types as that's technically not type sugar.

Reviewed By: jarin

Differential Revision: https://reviews.llvm.org/D87481

[ARM][TTI] Prevents constants in a min(max) or max(min) pattern from being hoisted when in a loop

Changes TTI function getIntImmCostInst to take an additional Instruction parameter,
which enables us to be able to check it is part of a min(max())/max(min()) pattern that will match SSAT.
We can then mark the constant used as free to prevent it being hoisted so SSAT can still be generated.
Required minor changes in some non-ARM backends to allow for the optional parameter to be included.

Differential Revision: https://reviews.llvm.org/D87457

[SCEV] Handle `less` predicates for FoundPred = NE

Currently these predicates are ignored, yet their handling is
pretty simple. I could not find a single test where it would
actually change something, but it's only because isImpliedCondOperands
is not smart enough to prove it further on. Yet the situation when
we come there with `less` predicate is pretty common.

Differential Revision: https://reviews.llvm.org/D87890
Reviewed By: fhahn

[SystemZ][z/OS] Set default wchar_t type for zOS

Set the default wchar_t type on z/OS, and unsigned as the default.

Reviewed By: hubert.reinterpretcast, fanbo-meng

Differential Revision: https://reviews.llvm.org/D87624

[LLD][PowerPC][test] Update thunk range error report for PPC64PCRelLongBranchThunk

Update the thunk range error report for PPC64PCRelLongBranchThunk and add a range
error test case for PPC64R12SetupStub.

Differential Revision: https://reviews.llvm.org/D87381

[ARM] Trying to fix asan buildbot

[libc++] NFC: Remove trailing whitespace from the feature test macro table

[SLP] Merge null and dyn_cast<> checks into dyn_cast_or_null<>. NFCI.

[MLIR][Standard] Add `atan` to standard dialect

Differential Revision: https://reviews.llvm.org/D88091

[SyntaxTree] Add tests for the assignment of the `canModify` tag.

Differential Revision: https://reviews.llvm.org/D88077

[SLP] clean up code in gather(); NFC

1. Use range for-loop to avoid repeatedly accessing end index.
2. Better variable names.

[SLP] move misplaced code comments; NFC

[SLP] reduce code duplication for checking parent block; NFC

[PowerPC] Fix for compiler side issue in PCRelative Local Exec

Stop combining loads and stores with PPCISD::ADD_TLS before we can merge the
node with with TLS_LOCAL_EXEC_MAT_ADDR. The issue is that
TLS_LOCAL_EXEC_MAT_ADDR cannot be selected by itself and requires the previous
ADD_TLS node that goes with it. However, we sometimes try to combine ADD_TLS
with loads and stores that come after it. If this happens then the ADD_TLS is
removed and TLS_LOCAL_EXEC_MAT_ADDR cannot be selected.

While this bug fix will address the issue it my not be ideal from a performance
perspective as we may be able to add patterns to combine TLS_LOCAL_EXEC_MAT_ADDR
with ADD_TLS with the load and store that comes after it all in one. However,
this is beyond the scope of this patch.

Reviewed By: NeHuang

Differential Revision: https://reviews.llvm.org/D88030

[NFC][mlir] Remove llvm:: prefix from SmallVector in parallel pretty printer.

This prefix is unnecessary as SmallVector is re-exported in the mlir namespace.

Differential Revision: https://reviews.llvm.org/D88025

[AIX][clang][driver] Make sure crti[_64].o is linked in C++ mode

since crti is required for functional static initialization.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D87927

[X86] Cleanup/add namespace closure comments. NFCI.

Fixes some clang-tidy llvm-namespace-comment warnings.

[X86] Add missing namespace closure comments. NFCI.

Fixes some clang-tidy llvm-namespace-comment warnings.

[PeepholeOptimizer] Enhance the redundant COPY elimination.

- Eliminate redundant COPYs from the same register & subregister pair.

Differential Revision: https://reviews.llvm.org/D87939

[VPlan] Add dump() helper to VPValue & VPRecipeBase.

This provides a convenient way to print VPValues and recipes in a
debugger. In particular it saves the user from instantiating
VPSlotTracker to print recipes or values.

[lld-macho] minimally handle option -dynamic

Stifle the warning for unimplemented option `-dyamic`, since it is already the default. Add `Config::staticLink` and skeletal support for altering the flag, but otherwise leave the option `-static` as hidden and its warning in place.

Differential Revision: https://reviews.llvm.org/D88045

[AIX][compiler-rt] Use the AR/ranlib mode flag for 32-bit and 64-bit mode

since we will be building both 32-bit and 64-bit compiler-rt builtins
from a single configuration.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D87113

[libc++] Implement C++20's P0784 (More constexpr containers)

This commit adds std::construct_at, and marks various members of
std::allocator_traits and std::allocator as constexpr. It also adds
tests and turns the existing tests into hybrid constexpr/runtime tests.

Thanks to Richard Smith for initial work on this, and to Michael Park
for D69803, D69132 and D69134, which are superseded by this patch.

Differential Revision: https://reviews.llvm.org/D68364

[GVNSink][NewPM] Add GVNSinkPass to PassRegistry.def

[scudo][standalone] Remove the pthread key from the shared TSD

https://reviews.llvm.org/D87420 removed the uses of the pthread key,
but the key itself was left in the shared TSD registry. It is created
on registry initialization, and destroyed on registry teardown.

There is really no use for it now, so we can just remove it.

Differential Revision: https://reviews.llvm.org/D88046

[ThinLTO] Re-order modules for optimal multi-threaded processing

Re-use an optimizition from the old LTO API (used by ld64).
This sorts modules in ascending order, based on bitcode size, so that larger modules are processed first. This allows for smaller modules to be process last, and better fill free threads 'slots', and thusly allow for better multi-thread load balancing.

In our case (on dual Intel Xeon Gold 6140, Windows 10 version 2004, two-stage build), this saves 15 sec when linking `clang.exe` with LLD & `-flto=thin`, `/opt:lldltojobs=all`, no ThinLTO cache, -DLLVM_INTEGRATED_CRT_ALLOC=d:\git\rpmalloc.

Before patch: 102 sec
After patch: 85 sec

Inspired by the work done by David Callahan in D60495.

Differential Revision: https://reviews.llvm.org/D87966

[DI][ASan][NewPM] Fix some DebugInfo ASan tests under NPM

Sema: introduce `__attribute__((__swift_name__))`

This introduces the new `swift_name` attribute that allows annotating
APIs with an alternate spelling for Swift.  This is used as part of the
importing mechanism to allow interfaces to be imported with a new name
into Swift.  It takes a parameter which is the Swift function name.
This parameter is validated to check if it matches the possible
transformed signature in Swift.

This is based on the work of the original changes in
https://github.com/llvm/llvm-project-staging/commit/8afaf3aad2af43cfedca7a24cd817848c4e95c0c

Differential Revision: https://reviews.llvm.org/D87534
Reviewed By: Aaron Ballman, Dmitri Gribenko

[OpenMPOpt] Refactored "issue" and "wait" declarations for data map runtime call.

Refactored __tgt_target_data_begin_mapper_<issue|wait> to receive the handle as an input/output argument.
This given the compiler warning of returning the handle as copy.

Differential Revision: https://reviews.llvm.org/D88029

[lld-macho] Make lld::getInteger() tolerate leading "0x"/"0X" when base is 16

ld64 is cool with leading `0x` for hex command-line args, and we should be also.

Reviewed By: #lld-macho, int3

Differential Revision: https://reviews.llvm.org/D88065

[sanitizer_common] Add debug print to sysmsg.c

Silence 'warning: unused variable' when compiling with Clang 10.0

[DAG] Remove DAGTypeLegalizer::GenWidenVectorTruncStores (PR42046)

Just scalarize trunc stores - GenWidenVectorTruncStores does the same thing but is flawed (PR42046) and unused.

Differential Revision: https://reviews.llvm.org/D87708

[PowerPC] Implement the 128-bit Vector Divide Extended Builtins in Clang/LLVM

This patch implements the 128-bit vector divide extended builtins in Clang/LLVM.
These builtins map to the vdivesq and vdiveuq instructions respectively.

Differential Revision: https://reviews.llvm.org/D87729

[PowerPC] Implement Vector String Isolate Builtins in Clang/LLVM

This patch implements the vector string isolate (predicate and non-predicate
versions) builtins. The predicate builtins are custom selected within PPCISelDAGToDAG.

Differential Revision: https://reviews.llvm.org/D87671

[mlir] NFC: fix trivial typos under include directory

Reviewed By: mravishankar, jpienaar

Differential Revision: https://reviews.llvm.org/D88040

[mlir][ods] Make OpBuilder and OperationState optional

The OpBuilder is required to start with OpBuilder and OperationState, so remove
the need for the user to specify it. To make it simpler to update callers,
retain the legacy behavior for now and skip injecting OpBuilder/OperationState
when params start with OpBuilder.

Related to bug 47442.

Differential Revision: https://reviews.llvm.org/D88050

[SyntaxTree] Test the List API

Differential Revision: https://reviews.llvm.org/D87839

[ASTMatchers] Avoid recursion in ancestor matching to save stack space.

A recent change increased the stack size of memoizedMatchesAncestorOfRecursively
leading to stack overflows on real code involving large fold expressions.
It's not totally unreasonable to choke on very deep ASTs, but as common
infrastructure it's be nice if ASTMatchFinder is more robust.
(It already uses data recursion for the regular "downward" traversal.)

Differential Revision: https://reviews.llvm.org/D86964

[NFC][regalloc] Simplify/conform to style guide indvars in Greedy

Differential Revision: https://reviews.llvm.org/D88055

Version 0.5 of the new "TableGen Backend Developer's Guide."
Files modified to take comments into account.
MLIR documentation updated for new TableGen documentation files.

[Analyzer][WebKit] UncountedLocalVarsChecker

Differential Review: https://reviews.llvm.org/D83259

[gn build] Port 848d66fafd2

[gn build] Port 8a64689e264

[clang] Fix a typo-correction crash

We leave a dangling TypoExpr when typo-correction is performed
successfully in `checkArgsForPlaceholders`, which leads a crash in the
later TypoCorrection.

This code was added in https://github.com/llvm/llvm-project/commit/1586782767938df3a20f7abc4d8335c48b100bc4,
and it didn't seem to have enough test coverage.
The fix is to remove this part, and no failuer tests.

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D87815

[test][MC] Rehabilitate llvm/test/MC/COFF/bigobj.py

The subject test was not actually running. This patch adds the
relevant suffix to the list of lit case filename extensions for the
enclosing directory.

Minor adjustments are also made to deal with bit rot.

Reviewed By: daltenty

Differential Revision: https://reviews.llvm.org/D87122

[NFC] Replace tabs with spaces in PPCInstrPrefix.td

[InstCombine] For pow(x, +/-0.5), stop falling into pow(x, 1.5), etc. case

The current code for handling pow(x, y) where y is an integer plus 0.5
is not explicitly guarded against attempting to transform the case where
abs(y) is exactly 0.5.

The latter case is meant to be handled by `replacePowWithSqrt`. Indeed,
if the pow(x, integer+0.5) case proceeds past a certain point, it will
hit an assertion by attempting to form pow(x, 0) using `getPow`.

This patch adds an explicit check to prevent attempting the
pow(x, integer+0.5) transformation on pow(x, +/-0.5) as suggested during
the review of D87877. This has the effect of retaining the shrinking of
`pow` to `powf` when the `sqrt` libcall cannot be formed.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D88066

[lldb] Skip test_common_completion_process_pid_and_name with reproducers

This test launches a subprocess which will have a different PID during
capture and replay.

[lldb] Skip TestMiniDumpUUID with reproducers

The modules not getting orphaned is wreaking havoc when the UUIDs match
between tests.

[LoopInfo][NewPM] Fix tests in Analysis/LoopInfo under NPM

[test][NewPM] Pin do-nothing-intrinsic.ll to legacy PM

It tests CallGraph infra around the legacy PM which isn't relevant in NPM.

[NFC][CVP] Add tests for srem with potentially different sigdness domains

[CVP] Enhance SRem -> URem fold to work not just on non-negative operands

This is a continuation of 8d487668d09fb0e4e54f36207f07c1480ffabbfd,
the logic is pretty much identical for SRem:

Name: pos pos
Pre: C0 >= 0 && C1 >= 0
%r = srem i8 C0, C1
  =>
%r = urem i8 C0, C1

Name: pos neg
Pre: C0 >= 0 && C1 <= 0
%r = srem i8 C0, C1
  =>
%r = urem i8 C0, -C1

Name: neg pos
Pre: C0 <= 0 && C1 >= 0
%r = srem i8 C0, C1
  =>
%t0 = urem i8 -C0, C1
%r = sub i8 0, %t0

Name: neg neg
Pre: C0 <= 0 && C1 <= 0
%r = srem i8 C0, C1
  =>
%t0 = urem i8 -C0, -C1
%r = sub i8 0, %t0

https://rise4fun.com/Alive/Vd6

Now, this new logic does not result in any new catches
as of vanilla llvm test-suite + RawSpeed.
but it should be virtually compile-time free,
and it may be important to be consistent in their handling,
because if we had a pair of sdiv-srem, and only converted one of them,
-divrempairs will no longer see them as a pair,
and thus not "merge" them.

[ConstantRange] binaryXor(): special-case binary complement case - the result is precise

Use the fact that `~X` is equivalent to `-1 - X`, which gives us
fully-precise answer, and we only need to special-handle the wrapped case.

This fires ~16k times for vanilla llvm test-suite + RawSpeed.

[ConstantRange] Introduce getActiveBits() method

Much like APInt::getActiveBits(), computes how many bits are needed
to be able to represent every value in this constant range,
treating the values as unsigned.

[NFC][CVP] processUDivOrURem(): refactor to use ConstantRange::getActiveBits()

As an exhaustive test shows, this logic is fully identical to the old
implementation, with exception of the case where both of the operands
had empty ranges:

```
TEST_F(ConstantRangeTest, CVP_UDiv) {
  unsigned Bits = 4;
  EnumerateConstantRanges(Bits, [&](const ConstantRange &CR0) {
    if(CR0.isEmptySet())
      return;
    EnumerateConstantRanges(Bits, [&](const ConstantRange &CR1) {
      if(CR0.isEmptySet())
        return;

      unsigned MaxActiveBits = 0;
      for (const ConstantRange &CR : {CR0, CR1})
        MaxActiveBits = std::max(MaxActiveBits, CR.getActiveBits());

      ConstantRange OperandRange(Bits, /*isFullSet=*/false);
      for (const ConstantRange &CR : {CR0, CR1})
        OperandRange = OperandRange.unionWith(CR);
      unsigned NewWidth = OperandRange.getUnsignedMax().getActiveBits();

      EXPECT_EQ(MaxActiveBits, NewWidth) << CR0 << " " << CR1;
    });
  });
}
```

[NFC][APInt] Refactor getMinSignedBits() in terms of getNumSignBits()

This is fully identical to the old implementation, just easier to read.

[ConstantRange] Introduce getMinSignedBits() method

Similar to the ConstantRange::getActiveBits(), and to similarly-named
methods in APInt, returns the bitwidth needed to represent
the given signed constant range

[NFC][CVP] Give a better name STATISTIC() counting udiv i16 -> udiv i8 xforms

[NFC][CVP] Add tests for SDiv/SRem narrowing

[CVP] Narrow SDiv/SRem to the smallest power-of-2 that's sufficient to contain its operands

This is practically identical to what we already do for UDiv/URem:
  https://rise4fun.com/Alive/04K

Name: narrow udiv
Pre: C0 u<= 255 && C1 u<= 255
%r = udiv i16 C0, C1
  =>
%t0 = trunc i16 C0 to i8
%t1 = trunc i16 C1 to i8
%t2 = udiv i8 %t0, %t1
%r = zext i8 %t2 to i16

Name: narrow exact udiv
Pre: C0 u<= 255 && C1 u<= 255
%r = udiv exact i16 C0, C1
  =>
%t0 = trunc i16 C0 to i8
%t1 = trunc i16 C1 to i8
%t2 = udiv exact i8 %t0, %t1
%r = zext i8 %t2 to i16

Name: narrow urem
Pre: C0 u<= 255 && C1 u<= 255
%r = urem i16 C0, C1
  =>
%t0 = trunc i16 C0 to i8
%t1 = trunc i16 C1 to i8
%t2 = urem i8 %t0, %t1
%r = zext i8 %t2 to i16

... only here we need to look for 'min signed bits', not 'active bits',
and there's an UB to be aware of:
  https://rise4fun.com/Alive/KG86
  https://rise4fun.com/Alive/LwR

Name: narrow sdiv
Pre: C0 <= 127 && C1 <= 127 && C0 >= -128 && C1 >= -128
%r = sdiv i16 C0, C1
  =>
%t0 = trunc i16 C0 to i9
%t1 = trunc i16 C1 to i9
%t2 = sdiv i9 %t0, %t1
%r = sext i9 %t2 to i16

Name: narrow exact sdiv
Pre: C0 <= 127 && C1 <= 127 && C0 >= -128 && C1 >= -128
%r = sdiv exact i16 C0, C1
  =>
%t0 = trunc i16 C0 to i9
%t1 = trunc i16 C1 to i9
%t2 = sdiv exact i9 %t0, %t1
%r = sext i9 %t2 to i16

Name: narrow srem
Pre: C0 <= 127 && C1 <= 127 && C0 >= -128 && C1 >= -128
%r = srem i16 C0, C1
  =>
%t0 = trunc i16 C0 to i9
%t1 = trunc i16 C1 to i9
%t2 = srem i9 %t0, %t1
%r = sext i9 %t2 to i16


Name: narrow sdiv
Pre: C0 <= 127 && C1 <= 127 && C0 >= -128 && C1 >= -128 && !(C0 == -128 && C1 == -1)
%r = sdiv i16 C0, C1
  =>
%t0 = trunc i16 C0 to i8
%t1 = trunc i16 C1 to i8
%t2 = sdiv i8 %t0, %t1
%r = sext i8 %t2 to i16

Name: narrow exact sdiv
Pre: C0 <= 127 && C1 <= 127 && C0 >= -128 && C1 >= -128 && !(C0 == -128 && C1 == -1)
%r = sdiv exact i16 C0, C1
  =>
%t0 = trunc i16 C0 to i8
%t1 = trunc i16 C1 to i8
%t2 = sdiv exact i8 %t0, %t1
%r = sext i8 %t2 to i16

Name: narrow srem
Pre: C0 <= 127 && C1 <= 127 && C0 >= -128 && C1 >= -128 && !(C0 == -128 && C1 == -1)
%r = srem i16 C0, C1
  =>
%t0 = trunc i16 C0 to i8
%t1 = trunc i16 C1 to i8
%t2 = srem i8 %t0, %t1
%r = sext i8 %t2 to i16


The ConstantRangeTest.losslessSignedTruncationSignext test sanity-checks
the logic, that we can losslessly truncate ConstantRange to
`getMinSignedBits()` and signext it back, and it will be identical
to the original CR.

On vanilla llvm test-suite + RawSpeed, this fires 1262 times,
while the same fold for UDiv/URem only fires 384 times. Sic!

Additionally, this causes +606.18% (+1079) extra cases of
aggressive-instcombine.NumDAGsReduced, and +473.14% (+1145)
of aggressive-instcombine.NumInstrsReduced folds.

Implement a new kind of Pass: dynamic pass pipeline

Instead of performing a transformation, such pass yields a new pass pipeline
to run on the currently visited operation.
This feature can be used for example to implement a sub-pipeline that
would run only on an operation with specific attributes. Another example
would be to compute a cost model and dynamic schedule a pipeline based
on the result of this analysis.

Discussion: https://llvm.discourse.group/t/rfc-dynamic-pass-pipeline/1637

Recommit after fixing an ASAN issue: the callback lambda needs to be
allocated to a temporary to have its lifetime extended to the end of the
current block instead of just the current call expression.

Reviewed By: silvas

Differential Revision: https://reviews.llvm.org/D86392

Revert "[lldb] XFAIL TestMemoryHistory on Linux"

This reverts commit 7518006d75accd21325747430d6bced66b2c5ada.

This test apparently works on the Swift CI ubuntu bot, so it shouldn't be
XFAIL'd on Linux.

[flang][msvc] Add explicit function template argument to applyFunction. NFC.

Msvc has difficulties deducing the template argument here. The error message is:
```
basic-parsers.h(790,12): error C2672: 'applyFunction': no matching overloaded function found
```
Explicitly pass the first template argument to help it.

This patch is part of the series to make flang compilable with MS Visual Studio <http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html>.

Reviewed By: DavidTruby

Differential Revision: https://reviews.llvm.org/D87961

[flang][msvc] Add explicit function template argument to applyLamda. NFC.

Like in D87961, msvc has difficulties deducing the template argument. The error message is:
```
expr-parsers.cpp(383): error C2672: 'applyLambda': no matching overloaded function found
```
Explicitly pass the first template argument to help it.

This patch is part of the series to make flang compilable with MS Visual Studio <http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html>.

Reviewed By: DavidTruby

Differential Revision: https://reviews.llvm.org/D88001

[flang][msvc] Explicitly reference "this" inside closure. NFC.

The Microsoft compiler seems to have difficulties to decide between a const/non-const method of a captured object context in a closure. The error message is:
```
symbol.cpp(261): error C2668: 'Fortran::semantics::Symbol::detailsIf': ambiguous call to overloaded function
symbol.h(535): note: could be 'const D *Fortran::semantics::Symbol::detailsIf<Fortran::semantics::DerivedTypeDetails>(void) const'
symbol.h(534): note: or       'D *Fortran::semantics::Symbol::detailsIf<Fortran::semantics::DerivedTypeDetails>(void)'
symbol.cpp(261): note: while trying to match the argument list '()'
```
Explicitly using the this-pointer resolves this problem.

This patch is part of the series to make flang compilable with MS Visual Studio <http://lists.llvm.org/pipermail/flang-dev/2020-July/000448.html>.

Reviewed By: DavidTruby

Differential Revision: https://reviews.llvm.org/D88052

Revert "The wrong placement of add pass with optimizations led to -funique-internal-linkage-names being disabled."

This reverts commit 6950db36d33d85d18e3241ab6c87494c05ebe0fb.

Two patches to fix the broken build.
One to fix a C++ compiler warning.
One to allow Sphinx to find a new document.

[lldb][test] Remove accidental import pdb in 783dc7dc7ed7487d0782c2feb8854df949b98e69

[compiler-rt][AIX] Add CMake support for 32-bit Power builds

This patch enables support for building compiler-rt builtins for 32-bit
Power arch on AIX. For now, we leave out the specialized ppc builtin
implementations for 128-bit long double and friends since those will
need some special handling for AIX.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D87383

[ThinLTO] Option to bypass function importing.

This completes the circle, complementing -lto-embed-bitcode
(specifically, post-merge-pre-opt). Using -thinlto-assume-merged skips
function importing. The index file is still needed for the other data it
contains.

Differential Revision: https://reviews.llvm.org/D87949

[AArch64] Avoid pairing loads with same result reg

When pairing ldr instructions to an ldp instruction, we cannot pair two ldr
destination registers where one is a sub or super register of the other.

Reviewed By: fhahn

Differential Revision: https://reviews.llvm.org/D86906

[LoopInfo] empty() -> isInnermost(), add isOutermost()

Differential Revision: https://reviews.llvm.org/D82895

Revert "[CodeGen] emit CG profile for COFF object file"

This reverts commit 91aed9bf975f1e4346cc8f4bdefc98436386ced2, it is
causing link errors.

Small fixes for "[LoopInfo] empty() -> isInnermost(), add isOutermost()"

Change LoopInfo::empty to isInnermost after D82895

[libc++] Implement LWG1203

Libc++ had an issue where nonsensical code like

  decltype(std::stringstream{} << std::vector<int>{});

would compile, as long as you kept the expression inside decltype in
an unevaluated operand. This turned out to be that we didn't implement
LWG1203, which clarifies what we should do in that case.

rdar://58769296

Fix build due to renaming in LoopInfo.

[AArch64] Teach analyzeBranch to remove branch equivelent to fallthrough

The motivation here is that MachineBlockPlacement relies on analyzeBranch to remove branches to fallthrough blocks when the branch is not fully analyzeable. With the introduction of the FAULTING_OP psuedo for implicit null checking (see D87861), this case becomes important. Note that it's hard to otherwise exercise this path as BranchFolding handle's any fully analyzeable branch sequence without using this interface.

p.s. For anyone who saw my comment in the original review, what I thought was an issue in BranchFolding originally turned out to simply be a bug in my patch. (Now fixed.)

Differential Revision: https://reviews.llvm.org/D88035

[libc++] NFC: Collocate C++20 removed members of std::allocator

[libc++] NFC: Reindent the feature test macro generation script

Each feature-test macro is now a clear block indentation-wise.

[SLP]Fix coding style, NFC.

Update recipe for flang-aarch64 slaves

- Update compiler location for flang-aarch64-ubuntu-{clang and gcc10}
- Add another email to the extra recipient for flang-aarch64
- Make flang-aarch64 slaves build new flang driver by default
- Add a missing coma to flang-aarch64-ubuntu-gcc10 recipe

Differential Revision: https://reviews.llvm.org/D87125

clang-x86-ninja-win10 - replacing backslashes

in buildbot.tac with forward slashes to address re-configuration
cycles in cmake