Previously, we formed ISD::PARITY by looking for (and (ctpop X), 1)
but the AND might be separated from the ctpop. For example if the
parity result is multiplied by 2, we'll pull the AND through the
shift.

So to handle more cases, move to SimplifyDemandedBits where we
can handle more cases that result in only the LSB of the CTPOP
being used.

gcov 4.7 introduced the two options.
https://sourceware.org/pipermail/gcc-patches/2011-November/328782.html

-r only dumps files with relative paths or absolute paths with the prefix
specified by -s. The two options are useful filtering out system header files.

As well as vector commuted operands.

Reduces the chance of confusion when calling the function with
autocomplete (will show the more accurate/informative variable name),
etc.

Turns out this was use-after-move of function_ref, which is trivially
copyable and movable, so the move did nothing and use after move was
safe.

But since this function_ref is being copied into a std::function, change
the function_ref to be std::function to avoid extra layers of type
erasure indirection - and then it's a real use after move, and fix that
by referring to the moved-to member variable rather than the moved-from
parameter.

[SelectionDAG] Remove default for 'unsigned' Alignment for getLoad/getStore/getExtLoad/getTruncStore. Add default for MaybeAlign version. NFCI

We want to remove the unsigned signatures eventually. This change
migrates any that don't explicitly pass an alignment.

Right now the ASTImporter assumes for most Expr nodes that they are always equal
which leads to non-compatible declarations ending up being merged. This patch
adds the basic framework for comparing Stmts (and with that also Exprs) and
implements the custom checks for a few Stmt subclasses. I'll implement the
remaining subclasses in follow up patches (mostly because there are a lot of
subclasses and some of them require further changes like having GNU language in
the testing framework)

The motivation for this is that in LLDB we try to import libc++ source code and
some of the types we are importing there contain expressions (e.g. because they
use `enable_if<expr>`), so those declarations are currently merged even if they
are completely different (e.g. `enable_if<value> ...` and `enable_if<!value>
...` are currently considered equal which is clearly not true).

Reviewed By: martong, balazske

Differential Revision: https://reviews.llvm.org/D87444

DAG combiner folds (fma a 1.0 b) into (fadd a b) but the flag isn't
propagated into new fadd. This patch fixes that.

Some code in visitFMA is redundant and such support for vector constants
is missing. Need follow-up patch to clean.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D87037

The recently added optimizePhiType algorithm had no checks to make sure
it didn't continually iterate backward and forth between float and int
types. This means that given an input like store(phi(bitcast(load))), we
could convert that back and forth to store(bitcast(phi(load))). This
particular case would usually have been simplified to a different load
type (folding the bitcast into the load) before CGP, but other cases can
occur. The one that came up was phi(bitcast(phi)), where the two phi's
of different types were bitcast between. That was not helped by a dead
bitcast being kept around which could make conversion look profitable.

This adds an extra check of the bitcast Uses or Defs, to make sure that
at least one is grounded and will not end up being converted back. It
also makes sure that dead bitcasts are removed, and there is a minor
change to include newly created Phi nodes in the Visited set so that
they do not need to be revisited.

Differential Revision: https://reviews.llvm.org/D82676

Demonstrates that redundant masked stores may be removed, as long as we're able to replace the AVX/AVX2 masked store with a generic masked store (constant mask or sign-extended bool vector mask).

Commit 3c0b3250 introduced store fusion for PowerPC target, but it
brought failure under UB sanitizer and was reverted. This patch fixes
them.

This is weird.

gcov is an "Edge Profiling with Edge Counters" application according to
Optimally Profiling and Tracing Programs (1994).

The minimum number of counters necessary is |E|-(|V|-1). The unmeasured edges
form a spanning tree. Both GCC --coverage and clang -fprofile-generate leverage
this optimization. This patch implements the optimization for clang --coverage.
The produced .gcda files are much smaller now.

This makes the generated IR much more readable.

Also guard against infinite recursion if GCOV_ARC_ON_TREE edges contain a cycle.

Adds link/code sample to avoid rendering two dashes as non-ASCII "en dash".
Also make wording a complete sentence.

Reviewed By: nickdesaulniers, tmfink

Differential Revision: https://reviews.llvm.org/D85596

CTTZ, CTLZ, CTPOP, and FCANONICALIZE all have the same input and
output types so the operand should have already been legalized when the
result type was legalized.

[X86] Use ISD::PARITY directly instead of emitting CTPOP and AND from combineHorizontalPredicateResult.

We have a PARITY ISD node now so might as well use it. It will
get re-expanded later.

Differential Revision: https://reviews.llvm.org/D77187

Also add the +mutable-globals features in clang when
building with `-fPIC` since the linker will generate mutable
globals imports and exports in that case.

Differential Revision: https://reviews.llvm.org/D87537

[gcov] Process .gcda immediately after the accompanying .gcno instead of doing all .gcda after all .gcno

i.e. change the work flow from

* .gcno for function A
* .gcno for function B
* .gcno for function C
* .gcda for function A
* .gcda for function B
* .gcda for function C

to

* .gcno for function A
* .gcda for function A
* .gcno for function B
* .gcda for function B
* .gcno for function C
* .gcda for function C

Currently there is duplicate logic in .gcno & .gcda processing: how functions
are filtered, which edges are instrumented, etc. This refactor enables simplification.

Since we always process .gcno, in -fprofile-arcs -fno-test-coverage mode,
__llvm_internal_gcov_emit_function_args.0 will have non-zero checksums.

Revert "[gcov] emitProfileArcs: iterate over GCOVFunction's instead of Function's to avoid duplicated filtering"

This reverts commit 412c9c0b.

[gcov] emitProfileArcs: iterate over GCOVFunction's instead of Function's to avoid duplicated filtering

It builds fine for MinGW on Windows.

Differential Revision: https://reviews.llvm.org/D87539

It builds without errors and makes possible to use
CLANG_LINK_CLANG_DYLIB=1.

Differential Revision: https://reviews.llvm.org/D87547

In MinGW world, UNIX like lib prefix is preferred for the libraries.
This patch adjusts CMake files to do that.

Differential Revision: https://reviews.llvm.org/D87517

[SelectionDAG][X86][ARM][AArch64] Add ISD opcode for __builtin_parity. Expand it to shifts and xors.

Clang emits (and (ctpop X), 1) for __builtin_parity. If ctpop
isn't natively supported by the target, this leads to poor codegen
due to the expansion of ctpop being more complex than what is needed
for parity.

This adds a DAG combine to convert the pattern to ISD::PARITY
before operation legalization. Type legalization is updated
to handled Expanding and Promoting this operation. If after type
legalization, CTPOP is supported for this type, LegalizeDAG will
turn it back into CTPOP+AND. Otherwise LegalizeDAG will emit a
series of shifts and xors followed by an AND with 1.

I've avoided vectors in this patch to avoid more legalization
complexity for this patch.

X86 previously had a custom DAG combiner for this. This is now
moved to Custom lowering for the new opcode. There is a minor
regression in vector-reduce-xor-bool.ll, but a follow up patch
can easily fix that.

Fixes PR47433

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D87209