Changes

Move code for checking loop metadata into Analysis [nfc]

I need the mustprogress loop metadata in ScalarEvolution and it makes sense to keep all the accessors for quering loop metadate together.

Move variable only used inside an assert into the assert.

This prevents build failures with -Wunused.

[SCEV] Use mustprogress flag on loops (in addition to function attribute)

This addresses a performance regression reported against 3c6e4191.  That change (correctly) limited a transform based on assumed finiteness to mustprogress loops, but the previous change (38540d7) which introduced the mustprogress check utility only handled function attributes, not the loop metadata form.

It turns out that clang uses the function attribute form for C++, and the loop metadata form for C.  As a result, 3c6e4191 ended up being a large regression in practice for C code as loops weren't being considered mustprogress despite the language semantics.

[ELF][RISCV] Resolve branch relocations referencing undefined weak to current location if not using PLT

In a -no-pie link we optimize R_PLT_PC to R_PC. Currently we resolve a branch
relocation to the link-time zero address. However such a choice tends to cause
relocation overflow possibility for RISC architectures.

* aarch64: GNU ld: rewrite the instruction to a NOP; ld.lld: branch to the next instruction
* mips: GNU ld: branch to the start of the text segment (?); ld.lld: branch to zero
* ppc32: GNU ld: rewrite the instruction to a NOP; ld.lld: branch to the current instruction
* ppc64: GNU ld: rewrite the instruction to a NOP; ld.lld: branch to the current instruction
* riscv: GNU ld: branch to the absolute zero address (with instruction rewriting)
* i386/x86_64: GNU ld/ld.lld: branch to the link-time zero address

I think that resolving to the same location is a good choice. The instruction,
if triggered, is clearly an undefined behavior. Resolving to the same location
can cause an infinite loop (making the user aware of the issue) while ensuring
no overflow.

Reviewed By: jrtc27

Differential Revision: https://reviews.llvm.org/D103001

[ELF] Simplify getAArch64UndefinedRelativeWeakVA. NFC

[libc++] Remove unnecessary header in enable_view.h (which caused a cycle)

[LI] Add a cover function for checking if a loop is mustprogress [nfc]

Essentially, the cover function simply combines the loop level check and the function level scope into one call.  This simplifies several callers and is (subjectively) less error prone.

[ARM] Fix Changed status in MVEGatherScatterLoweringPass.

Now that we are calling SimplifyInstructionsInBlock, make sure we update
Changed when it reports alterations.

[clang] NRVO: Improvements and handling of more cases.

This expands NRVO propagation for more cases:

Parse analysis improvement:
* Lambdas and Blocks with dependent return type can have their variables
  marked as NRVO Candidates.

Variable instantiation improvements:
* Fixes crash when instantiating NRVO variables in Blocks.
* Functions, Lambdas, and Blocks which have auto return type have their
  variables' NRVO status propagated. For Blocks with non-auto return type,
  as a limitation, this propagation does not consider the actual return
  type.

This also implements exclusion of VarDecls which are references to
dependent types.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: Quuxplusone

Differential Revision: https://reviews.llvm.org/D99696

[SimplifyCFG] avoid 'tmp' variables in test file; NFC

[LV] Parallel annotated loop does not imply all loads can be hoisted.

As noted in https://bugs.llvm.org/show_bug.cgi?id=46666, the current behavior of assuming if-conversion safety if a loop is annotated parallel (`!llvm.loop.parallel_accesses`), is not expectable, the documentation for this behavior was since removed from the LangRef again, and can lead to invalid reads.
This was observed in POCL (https://github.com/pocl/pocl/issues/757) and would require similar workarounds in current work at hipSYCL.

The question remains why this was initially added and what the implications of removing this optimization would be.
Do we need an alternative mechanism to propagate the information about legality of if-conversion?
Or is the idea that conditional loads in `#pragma clang loop vectorize(assume_safety)` can be executed unmasked without additional checks flawed in general?
I think this implication is not part of what a user of that pragma (and corresponding metadata) would expect and thus dangerous.

Only two additional tests failed, which are adapted in this patch. Depending on the further direction force-ifcvt.ll should be removed or further adapted.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D103907

2d Arm Neon sdot op, and lowering to the intrinsic.

This adds Sdot2d op, which is similar to the usual Neon
intrinsic except that it takes 2d vector operands, reflecting the
structure of the arithmetic that it's performing: 4 separate
4-dimensional dot products, whence the vector<4x4xi8> shape.

This also adds a new pass, arm-neon-2d-to-intr, lowering
this new 2d op to the 1d intrinsic.

Reviewed By: nicolasvasilache

Differential Revision: https://reviews.llvm.org/D102504

[MLIR] Document that Dialect Conversion traverses in preorder

Reviewed By: rriddle

Differential Revision: https://reviews.llvm.org/D102525

[AArch64][GlobalISel] Legalize scalar G_CTTZ + G_CTTZ_ZERO_UNDEF

This adds legalization for scalar G_CTTZ and G_CTTZ_ZERO_UNDEF. Vector support
requires handling vector G_BITREVERSE, which I haven't gotten around to yet.

For G_CTTZ_ZERO_UNDEF, we just lower it to G_CTTZ.

For G_CTTZ, we match SelectionDAG's lowering to a G_BITREVERSE + G_CTLZ.

e.g. https://godbolt.org/z/nPEseYh1s

(With this patch, we have slightly worse codegen than SDAG for types smaller
than s32; it seems like we're missing a combine.)

Also, this adds in a function to build G_BITREVERSE to MachineIRBuilder.

Differential Revision: https://reviews.llvm.org/D104065

[libcxx][ranges] removes default_initializable from weakly_incrementable and view

also:

* removes default constructors from predefined iterators
* makes span and string_view views

Partially implements P2325.
Partially resolves LWG3326.

Differential Revision: https://reviews.llvm.org/D102468

Preserve more MD_mem_parallel_loop_access and MD_access_group in SROA

SROA sometimes preserves MD_mem_parallel_loop_access and MD_access_group metadata on loads/stores, and sometimes fails to do so. This change adds copying of the MD after other CreateAlignedLoad/CreateAlignedStores. Also fix a case where the metadata was being copied from a load, rather than the store.

Added a LIT test to catch one case.

Patch by Mark Mendell

Differential Revision: https://reviews.llvm.org/D103254

[clang] Implement P2266 Simpler implicit move

This Implements [[http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2021/p2266r1.html|P2266 Simpler implicit move]].

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: Quuxplusone

Differential Revision: https://reviews.llvm.org/D99005

[Profile] Handle invalid profile data

This mostly follows LLVM's InstrProfReader.cpp error handling.
Previously, attempting to merge corrupted profile data would result in
crashes. See https://crbug.com/1216811#c4.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D104050

[IR] make -warn-frame-size into a module attr

-Wframe-larger-than= is an interesting warning; we can't know the frame
size until PrologueEpilogueInsertion (PEI); very late in the compilation
pipeline.

-Wframe-larger-than= was propagated through CC1 as an -mllvm flag, then
was a cl::opt in LLVM's PEI pass; this meant it was dropped during LTO
and needed to be re-specified via -plugin-opt.

Instead, make it part of the IR proper as a module level attribute,
similar to D103048. Introduce -fwarn-stack-size CC1 option.

Reviewed By: rsmith, qcolombet

Differential Revision: https://reviews.llvm.org/D103928

[Profile] Remove redundant check

This is already checked outside the loop.

Followup to D104050.

LoadStoreVectorizer: support different operand orders in the add sequence match

First we refactor the code which does no wrapping add sequences
match: we need to allow different operand orders for
the key add instructions involved in the match.

Then we use the refactored code trying 4 variants of matching operands.

Originally the code relied on the fact that the matching operands
of the two last add instructions of memory index calculations
had the same LHS argument. But which operand is the same
in the two instructions is actually not essential, so now we allow
that to be any of LHS or RHS of each of the two instructions.
This increases the chances of vectorization to happen.

Reviewed By: volkan

Differential Revision: https://reviews.llvm.org/D103912

[static initializers] Emit global_ctors and global_dtors in reverse order when .ctors/.dtors are used.

Reviewed By: rnk, MaskRay, efriedma

Differential Revision: https://reviews.llvm.org/D103495

[IR] Value: Fix OpCode checks

Value::SubclassID cannot be directly compared to Instruction enums, such as
Instruction::{Call,Invoke,CallBr}. We have to first subtract InstructionVal
from the SubclassID to get the OpCode, similar to Instruction::getOpCode().

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D104043

[RISCV] Add test cases that show failure to use some W instructions if they are proceeded by a load. NFC

The loads end up becoming sextload/zextload which prevent our
isel patterns from finding the sign_extend_inreg or AND instruction
we need.

The easiest way to fix this is to use computeKnownBits or
ComputeNumSignBits in our isel matching to catch this.

[SDAG] Fix pow2 assumption when splitting vectors

When reducing vector builds to shuffles it possible that
the DAG combiner may try to extract invalid subvectors.

This happens as the existing code assumes vectors will be power
of 2 sizes, which is already untrue, but becomes more noticable
with v6 and v7 types.
Specifically the existing code assumes that half PowerOf2Ceil of
a given vector index will fit twice into a given vector.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D103880

[ValueTypes] Define MVTs for v6i32, v6f32, v7i32, v7f32

For use in AMDGPU selection DAG.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D103881

[AArch64][GlobalISel] Fix incorrectly generating uxtw/sxtw for addressing modes.

When the extend is from 8 or 16 bits, the addressing modes don't support those
extensions, but we weren't checking that and therefore always generated the 32->64b
extension mode. Fun.

Differential Revision: https://reviews.llvm.org/D104070

[mlir][IR] Move MemRefElementTypeInterface to a new BuiltinTypeInterfaces file

This allows for using other type interfaces in the builtin dialect, which currently results in a compile time failure (as it generates duplicate interface declarations).

[mlir] Add new SubElementAttr/SubElementType Interfaces

These interfaces allow for a composite attribute or type to opaquely provide access to any held attributes or types. There are several intended use cases for this interface. The first of which is to allow the printer to create aliases for non-builtin dialect attributes and types. In the future, this interface will also be extended to allow for SymbolRefAttr to be placed on other entities aside from just DictionaryAttr and ArrayAttr.

To limit potential test breakages, this revision only adds the new interfaces to the builtin attributes/types that are currently hardcoded during AsmPrinter alias generation. In a followup the remaining builtin attributes/types, and non-builtin attributes/types can be extended to support it.

Differential Revision: https://reviews.llvm.org/D102945

[mlir-ir-printing] Prefix the dump message with the split marker(// -----)

This allows for better interaction with tools (such as mlir-lsp-server), as it separates the IR into separate modules for consecutive dumps.

Differential Revision: https://reviews.llvm.org/D104073

[Flang] Compile fix after D99459.

Fix Flang build after addition of a new OpenMP clauses for a Clang
patch (D99459). Flang is using TableGen to generation the declaration
of clause checks and the new clause was missing a definiton.

[RISCV] Use ComputeNumSignBits/MaskedValueIsZero in RISCVDAGToDAGISel::selectSExti32/selectZExti32.

This helps us select W instructions in more cases. Most of the
affected tests have had the sign_extend_inreg or AND folded into
sextload/zextload.

Differential Revision: https://reviews.llvm.org/D104079

[VectorCombine] Fix alignment in single element store

This fixes the concern in single element store scalarization that the
alignment of new store may be larger than it should be. It calculates
the largest alignment if index is constant, and a safe one if not.

Reviewed By: lebedev.ri, spatel

Differential Revision: https://reviews.llvm.org/D103419