This caused miscompiles of Chromium (https://crbug.com/1023818). The reduced
repro is small enough to fit here:

  $ cat /tmp/a.c
  unsigned char f(unsigned char *p) {
    unsigned char result = 0;
    for (int shift = 0; shift < 1; ++shift)
      result |= p[0] << (shift * 8);
    return result;
  }
  $ bin/clang -O2 -S -o - /tmp/a.c | grep -A4 f:
  f:                                      # @f
          .cfi_startproc
  # %bb.0:                                # %entry
          xorl    %eax, %eax
          retq

That's nicely optimized, but I don't think it's the right result :-)

> Same as D60846 but with a fix for the problem encountered there which
> was a missing context adjustment in the handling of PHI nodes.
>
> The test that caused D60846 to be reverted was added in e15ab8f2.
>
> Reviewers: nikic, nlopes, mkazantsev,spatel, dlrobertson, uabelho, hakzsam
>
> Subscribers: hiraditya, bollu, llvm-commits
>
> Tags: #llvm
>
> Differential Revision: https://reviews.llvm.org/D69571

This reverts commit 57dd4b03.

Instruction ldi.fmt can be considered cheap enough to avoid spill and restore
of value that it produces since it's loaded from immediate.

Differential Revision: https://reviews.llvm.org/D69898

When a 64-bit triple is used emit an error if the CPU only supports
32-bit code.

Patch by Miloš Stojanović.

Differential Revision: https://reviews.llvm.org/D70018

Adding tests check all available CPUs on Mips.

Patch by Miloš Stojanović.

Differential Revision: https://reviews.llvm.org/D70017

Add the remaining half (fp16) vector data load and store builtin
functions from the OpenCL C specification.

Patch by Pierre Gondois and Sven van Haastregt.

Revert due to sanitizer-windows buildbot failure.

This reverts commit bbb29738.

Summary:
Entry values are considered for parameters that have register-described
DBG_VALUEs in the entry block (along with other conditions).

If a parameter's value has been propagated from the caller to the
callee, then the parameter's DBG_VALUE in the entry block may be
described using a register defined by some instruction, and entry values
should not be emitted for the parameter, which can currently occur.
One such case was seen in the attached test case, in which the second
parameter, which is described by a redefinition of the first parameter's
register, would incorrectly get an entry value using the first
parameter's register. This commit intends to solve such cases by keeping
track of register defines, and ignoring DBG_VALUEs in the entry block
that are described by such registers.

In a RelWithDebInfo build of clang-8, the average size of the set was
27, and in a RelWithDebInfo+ASan build it was 30.

Reviewers: djtodoro, NikolaPrica, aprantl, vsk

Reviewed By: djtodoro, vsk

Subscribers: hiraditya, llvm-commits

Tags: #debug-info, #llvm

Differential Revision: https://reviews.llvm.org/D69889

Summary:
The conditions that are used to determine if entry values should be
emitted for a parameter are quite many, and will grow slightly
in a follow-up commit, so move those to a helper function, as was
suggested in the code review for D69889.

Reviewers: djtodoro, NikolaPrica

Reviewed By: djtodoro

Subscribers: probinson, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69955

This patch allows the register allocator to spill SVE registers to the stack.

Reviewers: ostannard, efriedma, rengolin, cameron.mcinally

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D70082

In case when all incoming values of a PHI are equal pointers, this
transformation inserts a definition of such a pointer right after
definition of the base pointer and replaces with this value both PHI and
all it's incoming pointers. Primary goal of this transformation is
canonicalization of this pattern in order to enable optimizations that
can't handle PHIs. Non-inbounds pointers aren't currently supported.

Reviewers: spatel, RKSimon, lebedev.ri, apilipenko

Reviewed By: apilipenko

Tags: #llvm

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D68128

This patch adds a target interface to set the StackID for a given type,
which allows scalable vectors (e.g. `<vscale x 16 x i8>`) to be assigned a
'sve-vec' StackID, so it is allocated in the SVE area of the stack frame.

Reviewers: ostannard, efriedma, rengolin, cameron.mcinally

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D70080

MVE includes instructions that extract an 8- or 16-bit lane from a
vector and sign-extend it into the output 32-bit GPR. `ARMInstrMVE.td`
already included isel patterns to select those instructions in
response to the `ARMISD::VGETLANEs` selection-DAG node type. But
`ARMISD::VGETLANEs` was never actually generated, because the code
that creates it was conditioned on NEON only.

It's an easy fix to enable the same code for integer MVE, and now IR
that sign-extends the result of an extractelement (whether explicitly
or as part of the function call ABI) will use `vmov.s8` instead of
`vmov.u8` followed by `sxtb`.

Reviewers: SjoerdMeijer, dmgreen, ostannard

Subscribers: kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70132

Summary:
Replaces
```
unsigned getShiftAmountThreshold(EVT VT)
```
by

```
bool shouldAvoidTransformToShift(EVT VT, unsigned amount)
```
thus giving more flexibility for targets to decide whether particular shift amounts must be considered expensive or not.

Updates the MSP430 target with a custom implementation.

This continues  D69116, D69120, D69326 and updates them, so all of them must be committed before this.

Existing tests apply, a few more have been added.

Reviewers: asl, spatel

Reviewed By: spatel

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70042

This is no longer needed after widening legalization as we
custom legalize v8i8 ourselves.

Added entries to the cost model, but bumped the cost slightly
to account for the truncate shuffle that wasn't costed before.

Commit 395124 "NVPTX: Don't insert an extra empty line at the end of the last section"
changed the length of the kernel payload. Update the regression test to the new binary size.

If lldb was run in capture mode, but no reproducer was generated, make
sure we clean up the reproducer directory.

Summary:
This patch adds a custom ISA for vector functions for internal use
in LLVM. The <isa> token is set to "_LLVM_", and it is not attached
to any specific instruction Vector ISA, or Vector Function ABI.

The ISA is used as a token for handling Vector Function ABI-style
vectorization for those vector functions that are not directly
associated to any existing Vector Function ABI (for example, some of
the vector functions exposed by TargetLibraryInfo). The demangling
function for this ISA in a Vector Function ABI context is set to be
the same as the common one shared between X86 and AArch64.

Reviewers: jdoerfert, sdesmalen, simoll

Subscribers: kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70089

8548 CPU is GCC's name for the e500v2, so accept this in clang.  The
e500v2 doesn't support lwsync, so define __NO_LWSYNC__ for this as well,
as GCC does.

Differential Revision:  https://reviews.llvm.org/D67787

This is the same as the add case, but inverts the operation type.

This avoids regressions in a future patch.

Previously this would default to 256, not the maximum supported size
of 1024. Using a maximum lower than the hardware maximum requires
language runtimes to enforce this limit for correctness, which no
language has correctly done. Switch the default to the conservatively
correct maximum, and force frontends to opt-in to the more optimal 256
default maximum.

I don't really understand why the changes in occupancy-levels.ll
increased the computed occupancy, which I expected to decrease. I'm
not sure if these tests should be forcing the old maximum.

While some targets allow encoding 2048, this was never tested or
supported.

This patch adds core definitions in lldb ArchSpecs for armv8l and armv7l cores.

This was needed because on Linux running on 32-bit Arm v8 we are returned
armv8l in case we are running 32-bit sysroot on 64bit kernel. In case of 32-bit
kernel and 32-bit sysroot running on arm v8 hardware we are returned armv7l.
This is quite common when we run 32 bit arm using docker container.

Signed-off-by: Muhammad Omair Javaid <omair.javaid@linaro.org>

Differential Revision: https://reviews.llvm.org/D69904

'clang'.

This is not true in practice in some content-addressed file systems.

This is a fix for PR43315. An assertion error is hit for this minimal example:

```
//clang -cc1 -triple x86_64-- -S tstVMStructRC-min.cpp
int (a b)();  // Assertion `Chunk.Kind == DeclaratorChunk::Function' failed.
```

This is because we do not cover the case in the FunctionTypeUnwrapper where it
receives a MacroQualifiedType. We have not run into this earlier because this
is a unique case where the __attribute__ contains both __cdecl__ and
__regparm__ (in that order), and we are compiling for x86_64. Changing the
architecture or the order of __cdecl__ and __regparm__ does not raise the
assertion.

Differential Revision: https://reviews.llvm.org/D67992

Reverting to figure out if it's a problem in python or the compiler for now.

This reverts commit 885a05f4.

A few years back a similar change was made for getenv since neither function is supported on the PS4 platform.

Recently, commit d889d1ef added a call to setenv in compiler-rt which was causing linking errors because the symbol was not found. This fixes that issue by putting in a shim similar to how we previously dealt with the lack of getenv.

Differential Revision: https://reviews.llvm.org/D70033

This avoids some nasty issues with argument passing and lowering of
arbitrary v64i8 shuffles.

[X86] Only pass v64i8/v32i16 as v16i32 on non-avx512bw targets if the v16i32 type won't be split by prefer-vector-width=256

Otherwise just let the v64i8/v32i16 types be split to v32i8/v16i16.

In reality this shouldn't happen because it means we have a 512-bit
vector argument, but min-legal-vector-width says a value less than
512. But a 512-bit argument should have been factored into the
preferred vector width.

Summary:
This patch fixes two problems with the crtbegin.c as written:

1. In do_init, register_frame_info is not guarded by a #define, but in
do_fini, deregister_frame_info is guarded by #ifndef
CRT_HAS_INITFINI_ARRAY. Thus when CRT_HAS_INITFINI_ARRAY is not
defined, frames are registered but then never deregistered.

The frame registry mechanism builds a linked-list from the .so's
static variable do_init.object, and when the .so is unloaded, this
memory becomes invalid and should be deregistered.

Further, libgcc's crtbegin treats the frame registry as independent
from the initfini array mechanism.

This patch fixes this by adding a new #define,
"EH_USE_FRAME_INFO_REGISTRY", which is set by the cmake option
COMPILER_RT_CRT_USE_EH_FRAME_REGISTRY Currently, do_init calls
register_frame_info, and then calls the binary's constructors. This
allows constructors to safely use libunwind. However, do_fini calls
deregister_frame_info and then calls the binary's destructors. This
prevents destructors from safely using libunwind.

This patch also switches that ordering, so that destructors can safely
use libunwind. As it happens, this is a fairly common scenario for
thread sanitizer.

Some warnings in -Wtautological-compare subgroups are DefaultIgnore.
Adding this group to -Wmost, which is part of -Wall, will aid in their
discoverability.

Differential Revision: https://reviews.llvm.org/D69292

Enable to generate BTF_KIND_VARs for non-static
default-section globals which is not allowed previously.
Modified the existing test case to accommodate the new change.

Also removed unused linkage enum members VAR_GLOBAL_TENTATIVE and
VAR_GLOBAL_EXTERNAL.

Differential Revision: https://reviews.llvm.org/D70145

Summary:
If there are any internal methods whose address was taken, conclude there is nothing known in relation of any other internal method and a global.

Reviewers: nlopes, sanjoy.google

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D69690

This fixes the following warning for developers:

  Target 'liblldb' was changed to a FRAMEWORK sometime after install().  This
  may result in the wrong install DESTINATION.  Set the FRAMEWORK property
  earlier.

The solution is to pass the FRAMEWORK flag to add_lldb_library and set
the target property before install(). For now liblldb is the only
customer.

Resolves PR38906, PR40898.

Summary:
By additional regex match, grouping of main include can be enabled in files that are not normally considered as a C/C++ source code.
For example, this might be useful in templated code, where template implementations are being held in *Impl.hpp files.
On the occassion, 'assume-filename' option description was reworded as it was misleading. It has nothing to do with `style=file` option and it does not influence sourced style filename.

Reviewers: rsmith, ioeric, krasimir, sylvestre.ledru, MyDeveloperDay

Reviewed By: MyDeveloperDay

Subscribers: MyDeveloperDay, cfe-commits

Patch by:  furdyna

Tags: #clang

Differential Revision: https://reviews.llvm.org/D67750