After loop interchange, the (old) outer loop header should not jump to
the `LoopExit`. Note that the old outer loop becomes the new inner loop
after interchange. If we branched to `LoopExit` then after interchange
we would jump directly from the (new) inner loop header to `LoopExit`
without executing the rest of outer loop.

This patch modifies adjustLoopBranches() such that the old outer
loop header (which becomes the new inner loop header) jumps to the
old inner loop latch which becomes the new outer loop latch after
interchange.

Reviewed By: bmahjour

Differential Revision: https://reviews.llvm.org/D98475

Add InstAlias that allows the last operand to be an imm for following instructions:

1. Zbb or Zbp:
    - ror
    - rorw (RV64 Only)

2. Zbs
    - best
    - bclr
    - binv
    - bext

Reviewed By: craig.topper, jrtc27

Differential Revision: https://reviews.llvm.org/D100083

The smax case shows up in https://llvm.org/PR49885 .
The others seem unlikely, but we might as well try
for uniformity (although that could mean an extra
instruction to create "nabs").

smax -- https://alive2.llvm.org/ce/z/8yYaGy
smin -- https://alive2.llvm.org/ce/z/0_7zc_
umax -- https://alive2.llvm.org/ce/z/EcsZWs
umin -- https://alive2.llvm.org/ce/z/Xw6WvB

The backend can't handle this and will throw a fatal error from
type legalization. It's easy enough to fix that for this intrinsic
by just splitting the IR intrinsic since it works on individual bytes.

There will be other intrinsics in the future that would be harder
to support through splitting, for example grev, gorc, and shfl. Those
would require a compare and a select be inserted to check the MSB of
their control input.

This patch adds support for preventing this in the frontend with
a nice diagnostic.

Reviewed By: frasercrmck

Differential Revision: https://reviews.llvm.org/D99984

clang++ uses llvm.compiler.used in certain cases to preserve
symbol which is fully inlined. D96087 has resulted in undefined
symbols in such cases. Set it to false by default to preserve
old behavior but keep the option for specific uses where we
want to ignore these (e.g. to detect a potential indirect call
to a function).

Differential Revision: https://reviews.llvm.org/D99897

Swift builds seem to use it. All it requires is emitting the
corresponding paths as STABS.

Fixes llvm.org/PR49385.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D100076

This reverts commit 3b9a15d9.

Added punctuation and changed "So for instance" to "For instance".

Fixes https://llvm.org/PR42017

Differential revision: https://reviews.llvm.org/D100053

Reviewed By: mravishankar

Differential Revision: https://reviews.llvm.org/D100112

This patch supports std::data and std::addressof functions.

rdar://73463300

Differential Revision: https://reviews.llvm.org/D99260

rdar://68954187

Differential Revision: https://reviews.llvm.org/D99181

Reverted due to failure on the sanitizer-x86_64-linux-fast bot.

This reverts commit e10493eb.

Watch for fork(2)/vfork(2) (also fork/vfork-style clone(2) on Linux)
notifications and explicitly detach the forked child process, and add
initial tests for these cases.  The code covers FreeBSD, Linux
and NetBSD process plugins.  There is no new user-visible functionality
provided -- this change lays foundations over subsequent work on fork
support.

Differential Revision: https://reviews.llvm.org/D98822

Also makes LINK_TEST customizable from commandline with `--test` option.

The tests compare IPC statistics that MCA provides with IPC values
measured on Cortex-A55 hardware. For hardware tests, each snippet is
run in a loop unrolled by 1000, and IPC is measured by linux-perf.

Several tests do not match the hardware: the skewed ALU is not
supported, LDR seem to be missing a forwarding path.

Differential Revision: https://reviews.llvm.org/D98174

Addresses an old TODO.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D100082

The test is loosely based off LLD-ELF's `thinlto.ll`. However, I
found that test questionable because the the -save_temps behavior it
checks for is identical regardless of whether we are running in single-
or multi-threaded mode. I tried writing a test based on `--time-trace`
but couldn't get it to run deterministically... so I've opted to just
skip checking that behavior for now.

Reviewed By: #lld-macho, gkm

Differential Revision: https://reviews.llvm.org/D99356

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D100114

During SelectionDAG, we must track the SDNodes that each SDDbgValue depends on
to compute its value. These are ultimately derived from the location operands to
the SDDbgValue, but were stored in a separate vector prior to this patch. This
resulted in cases where one of the lists was updated incorrectly, resulting in
crashes during compilation. This patch fixes the issue by directly recomputing
the dependency list from the SDDbgOperands in getDependencies().

Differential Revision: https://reviews.llvm.org/D99423

This is just to stop a future patch from optimizing away the things that
we actually want to check for.

This reverts commit 053dc958. It causes perf regressions - see discussion in D97116.

These tests were added in:
1daa48f0
59e422c9

malloc_zero.c and realloc_too_big.c fail when only
leak sanitizer is enabled.
http://lab.llvm.org:8011/#/builders/59/builds/1635
(also in an armv8 32 bit build)

(I would XFAIL them but the same test is run with
address and leak sanitizer enabled and that one does
pass)

If the debug info is missing the terminating null die, we would crash
when trying to access the nonexisting children/siblings. This was
discovered because the test case for D98619 accidentaly produced such
input.

The test is flaky (sleeps didn't help).

Look through copies to find more cases where the two values being
selected are identical. The motivation for this is just to be able to
remove the weird special case where tryFoldCndMask was called from
foldInstOperand, part way through folding a move-immediate into its
users, without regressing any lit tests.

Instead of passing the start value and the defined value to
widenPHIInstruction, pass the VPWidenPHIRecipe directly, which can be
used to get both (and more in future patches).

It is common to zero-initialize not only scalar variables,
but also structs.  This is also defensive programming and
we shouldn't complain about that.

rdar://34122265

Differential Revision: https://reviews.llvm.org/D99262

This allows mapping larger files, delaying OOM failures until too many
pages of them are accessed.  This is makes the behavior of the
mapped_file_region in this regard consistent between its "Unix" and
"Windows" implementations.

Guard the code witih #if defined(MAP_NORESERVE), consistent with other
uses of MAP_NORESERVE in llvm-project, because some FreeBSD versions do
not provide this flag.

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D96626

ScratchExecCopy needs to be marked as live, we cannot use that register
while EXEC is stored in there.

Marking SGPRForFPSaveRestoreCopy and SGPRForBPSaveRestoreCopy as
available is unnecessary, they should not be live at that point anway.

Differential Revision: https://reviews.llvm.org/D100098

Goes with D100095

Differential Revision: https://reviews.llvm.org/D99883