integer group:
vredsum/vredmaxu/vredmax/vredminu/vredmin/vredand/vredor/vredxor
float group:
vfredosum/vfredsum/vfredmax/vfredmin

We work with @rogfer01 from BSC to come out this patch.

Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Zakk Chen <zakk.chen@sifive.com>

Differential Revision: https://reviews.llvm.org/D93746

[LoopIdiom] 'left-shift-until-bittest': keep no-wrap flags on shift, fix edge-case miscompilation for %x.next

While `%x.curr` is always safe to compute, because `LoopBackedgeTakenCount`
will always be smaller than `bitwidth(X)`, i.e. we never get poison,
rewriting `%x.next` is more complicated, however, because `X << LoopTripCount`
will be poison iff `LoopTripCount == bitwidth(X)` (which will happen
iff `BitPos` is `bitwidth(x) - 1` and `X` is `1`).

So unless we know that isn't the case (as alive2 notes, we know it's safe
to do iff shift had no-wrap flags, or bitpos does not indicate signbit,
or we know that %x is never `1`), we'll need to emit an alternative,
safe IR, by either just shifting the `%x.curr`, or conditionally selecting
between the computed `%x.next` and `0`..
Former IR looks better so let's do that.

While there, ensure that we don't drop no-wrap flags from said shift.

In particular, add tests with no-wrap flags on shift,
a test where %x is not `1`, and ensure that tests where %bit
is a constant bitwidth-1, or is not a constant bitwidth-1
test both liveout values.

This is one of the deficiencies that can be observed in
https://godbolt.org/z/YPczsG after D91038 patch set.

This exposed two missing folds, one was fixed by the previous commit,
another one is `(A ^ B) | ~(A ^ B) --> -1` / `(A ^ B) & ~(A ^ B) --> 0`.

`-early-cse` will catch it: https://godbolt.org/z/4n1T1v,
but isn't meaningful to fix it in InstCombine,
because we'd need to essentially do our own CSE,
and we can't even rely on `Instruction::isIdenticalTo()`,
because there are no guarantees that the order of operands matches.
So let's just accept it as a loss.

```
----------------------------------------
define i32 @and_xor_not_common_op(i32 %a, i32 %b) {
%0:
  %b2 = xor i32 %b, 4294967295
  %t2 = xor i32 %a, %b2
  %t4 = and i32 %t2, %a
  ret i32 %t4
}
=>
define i32 @and_xor_not_common_op(i32 %a, i32 %b) {
%0:
  %t4 = and i32 %a, %b
  ret i32 %t4
}
Transformation seems to be correct!
```

... which is a variation of `a & (a ^ ~b)` --> a & b`.
A follow-up patch exposes this missing fold, so we need to fix it first.

A pattern to ignore ConstantExpr's is quite common, since they frequently
lead into infinite combine loops, so let's make writing it easier.

Thanks to Luke Benes for pointing it out.

The last use of the function was removed on Sep 13, 2010 in commit
1094c802.

Replace the local compute*SignedMinMaxValuesFromKnownBits methods with the equivalent KnownBits helpers to determine the min/max value ranges.

Add unit test coverage - a followup will update InstCombineCompares.cpp to use this and could be used by D86578 as well.

Update the comment to make this clear, following the same approach as APInt.

Make test case x86 specific.

Reviewed By: xbolva00

Differential Revision: https://reviews.llvm.org/D93803

This reverts commit 899faa50.

Upon further consideration, this does not fix the right issue.
Doing this fold for non-inbounds GEPs is legal, because the
resulting pointer is still based-on null, which has no associated
address range, and as such and access to it is UB.

https://bugs.llvm.org/show_bug.cgi?id=48577#c3

Currently 'resume' is lowered to _Unwind_Resume with out "noreturn" attribute. Semantically _Unwind_Resume  library call is expected to never return and should be marked as such. Though I didn't find any changes in behavior of existing tests there will be a difference once https://reviews.llvm.org/D79485 lands.

I was not able to come up with the test case anything better than just checking for presence of "noreturn" attribute. Please let me know if there is a better way to test the change.

Reviewed By: xbolva00

Differential Revision: https://reviews.llvm.org/D93682

Currently, the compiler crashes in instruction selection of global
load/stores in gfx600 due to the lack of FLAT instructions. This patch
fix the crash by selecting MUBUF instructions for global load/stores
in gfx600.

Authored-by: Praveen Velliengiri <Praveen.Velliengiri@amd.com>

Reviewed by: t-tye

Differential revision: https://reviews.llvm.org/D92483

This reverts commit eb79fd3c.

This causes stage2 crashes, possibly due to StringMap being
miscompiled. Reverting for now.

When something is wrong with the GNU hash table header we dump
its context as a raw data.

Currently we have the calculation overflow issue and it is possible to
bypass the validation we have (and crash).

The patch fixes it.

Differential revision: https://reviews.llvm.org/D93760

The function was introduced without a user on Jan 3, 2011 in commit
0f87ca77.  We still don't have a user
yet.

This adds tests in directories missing from https://reviews.llvm.org/rGdb7a2f347f132b3920415013d62d1adfb18d8d58

This commit copies existing tests at llvm/Transforms and replaces
'insertelement undef' in those files with 'insertelement poison'.
(see https://reviews.llvm.org/D93586)

Tests listed using this script:

grep -R -E '^[^;]*insertelement <.*> undef,' . | cut -d":" -f1 | uniq |
wc -l

Tests updated:

file_org=llvm/test/Transforms/$1
file=${file_org%.ll}-inseltpoison.ll
cp $file_org $file
sed -i -E 's/^([^;]*)insertelement <(.*)> undef/\1insertelement <\2> poison/g' $file
head -1 $file | grep "Assertions have been autogenerated by utils/update_test_checks.py" -q
if [ "$?" == 1 ]; then
  echo "$file : should be manually updated"
  # I manually updated the script
  exit 1
fi
python3 ./llvm/utils/update_test_checks.py --opt-binary=./build-releaseassert/bin/opt $file

Some predicates, can be considered the same as long as the operands are
flipped. For example, a > b gives the same result as b > a. This maps
instructions in a greater than form, to their appropriate less than
form, swapping the operands in the IRInstructionData only, allowing for
more flexible matching.

Tests:

llvm/test/Transforms/IROutliner/outlining-isomorphic-predicates.ll
llvm/unittests/Analysis/IRSimilarityIdentifierTest.cpp

Reviewers: jroelofs, paquette

Recommit of commit 05039266

Differential Revision: https://reviews.llvm.org/D87310

Fixes a bug introduced by D91589.

When folding `(sext (not i1 x)) -> (add (zext i1 x), -1)`, we try to replace the not first when possible. If we replace the not in-visit, then the now invalidated node will be returned, and subsequently we will return an invalid sext. In cases where the not is replaced in-visit we can simply return SDValue, as the not in the current sext should have already been replaced.

Thanks @jgorbe, for finding the below reproducer.

The following reduced test case crashes clang when built with `clang -O1 -frounding-math`:

```
template <class> class a {
  int b() { return c == 0.0 ? 0 : -1; }
  int c;
};
template class a<long>;
```

A debug build of clang produces this "assertion failed" error:
```
clang: /home/jgorbe/code/llvm/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:264: void {anonymous}::DAGCombiner::AddToWorklist(llvm::
SDNode*): Assertion `N->getOpcode() != ISD::DELETED_NODE && "Deleted Node added to Worklist"' failed.
```

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D93274

Add support for stdin to SourceManager and FileManager. Adds
FileManager::getSTDIN, which adds a FileEntryRef for `<stdin>` and reads
the MemoryBuffer, which is stored as `FileEntry::Content`.

Eventually the other buffers in `ContentCache` will sink to here as well
-- we probably usually want to load/save a MemoryBuffer eagerly -- but
it's happening early for stdin to get rid of
CompilerInstance::InitializeSourceManager's final call to
`SourceManager::overrideFileContents`.

clang/test/CXX/modules-ts/dcl.dcl/dcl.module/dcl.module.export/p1.cpp
relies on building a module from stdin; supporting that requires setting
ContentCache::BufferOverridden.

Differential Revision: https://reviews.llvm.org/D93148

Handle named pipes natively in SourceManager and FileManager, removing a
call to `SourceManager::overrideFileContents` in
`CompilerInstance::InitializeSourceManager` (removing a blocker for
sinking the content cache to FileManager (which will incidently sink
this new named pipe logic with it)).

SourceManager usually checks if the file entry's size matches the
eventually loaded buffer, but that's now skipped for named pipes since
the `stat` won't reflect the full size.  Since we can't trust
`ContentsEntry->getSize()`, we also need shift the check for files that
are too large until after the buffer is loaded... and load the buffer
immediately in `createFileID` so that no client gets a bad value from
`ContentCache::getSize`. `FileManager::getBufferForFile` also needs to
treat these files as volatile when loading the buffer.

Native support in SourceManager / FileManager means that named pipes can
also be `#include`d, and clang/test/Misc/dev-fd-fs.c was expanded to
check for that.

This is a new version of 3b18a594, which
was reverted in b3463220 since it was
missing the `SourceManager` changes.

Differential Revision: https://reviews.llvm.org/D92531

If we happen to extract a non-dword subreg that breaks the
logic of the function and it may shrink the dmask because
it does not recognize the use of a lane(s).

This bug is next to impossible to trigger with the current
lowering in the BE, but it breaks in one of my future patches.

Differential Revision: https://reviews.llvm.org/D93782

D93491 implemented `--version` for the MachO LLD port, but asserts that the string contains something like "LLD N.N". However, this is just the cmake default for `LLD_VERSION_STRING`, and downstream users may choose a different value, e.g. a rolling distro may print "LLD trunk".

Rename the basic block symbols in the test to reflect the new names.

Use early return to reduce the levels of indentation. Extract logic to
find object in container into helper function.

See https://github.com/clangd/clangd/issues/631

Reverting due to unit test errors between commits.

This reverts commit 05039266.

With which you can add a space before the colon of a case or default
statement.

Differential Revision: https://reviews.llvm.org/D93240

Differential Revision: https://reviews.llvm.org/D93163

As Nuno is noting in post-commit review in
https://reviews.llvm.org/D87188#2467915
it is not correct to keep NSW for negated abs pattern,
so don't do that.