Commit Graph

360247 Commits

Author SHA1 Message Date
Shuhong Liu 85bed2f381 [AIX] Remove diff -a option on llvm-cov.test
Summary:
llvm-cov.test generates .gcov files and compared with target
sample files. Since the files do not contain any binary data
(files are plain ASCII texts), remove -a from diff. And this
fix will the error on AIX since the default diff tool on AIX
does not support -a option.

Reviewers: hubert.reinterpretcast, daltenty, stevewan

Subscribers: llvm-commits

Tags: #LLVM

Differential Revision: https://reviews.llvm.org/D83711
2020-07-14 12:24:36 -04:00
Rahul Joshi 256d44811e [MLIR] [TableGen] Avoid generating an assert which is always true.
- Avoid generating "assert(resultTypes.size() >= 0u)" which is always true

Differential Revision: https://reviews.llvm.org/D83735
2020-07-14 09:19:52 -07:00
Michael Kruse 322e7cfab5 [docs] Update llvm.loop metadata documentation.
Loop metadata nodes do not adhere to the documented property:

(a) LoopIDs are not unique: Any pass that duplicates IR will do it
    including its metadata (e.g. LoopVersioning) such that multiple
    loops are linked with the same LoopID. There is even a test case
    (Transforms/LoopUnroll/unroll-pragmas-disabled.ll) for multiple
    loops with the same LoopID.

(b) LoopIDs are not persistent: Adding or removing an item from a LoopID
    can only be done by creating a new MDNode and assigning it to the
    loop's branch(es). Passes such as LoopUnroll (llvm.loop.unroll.disable)
    and LoopVectorize (llvm.loop.isvectorized) use this to mark loops to
    not be transformed multiple times or to avoid that a LoopVersioned
    original loop is transformed.

Update the documentation according to how llvm.loop is used in practice.

Differential Revision: https://reviews.llvm.org/D55290
2020-07-14 11:03:57 -05:00
Logan Smith 2c2a297bb6 [clang][NFC] Add 'override' keyword to virtual function overrides
This patch adds override to several overriding virtual functions that were missing the keyword within the clang/ directory. These were found by the new -Wsuggest-override.
2020-07-14 08:59:57 -07:00
Louis Dionne e1ca7a6522 [libc++] Fix building the benchmarks after introducing a target for cxx-headers
The libc++ headers were included twice, which broke the #include_next
logic.
2020-07-14 11:50:12 -04:00
Fred Riss a4a00ced0c [lldb/Module] Allow for the creation of memory-only modules
Summary:
This patch extends the ModuleSpec class to include a
DataBufferSP which contains the module data. If this
data is provided, LLDB won't try to hit the filesystem
to create the Module, but use only the data stored in
the ModuleSpec.

Reviewers: labath, espindola

Subscribers: emaste, MaskRay, lldb-commits

Tags: #lldb

Differential Revision: https://reviews.llvm.org/D83512
2020-07-14 08:45:44 -07:00
Jonas Devlieghere 706cccb889 [lldb] Make `process connect` blocking in synchronous mode.
In synchronous mode, the process connect command and its aliases should
wait for the stop event before claiming the command is complete.
Currently, the stop event is always handled asynchronously by the
debugger.

The implementation takes the same approach as Process::ResumeSynchronous
which hijacks the event and handles it on the current thread. Similarly,
after this patch, the stop event is part of the command return object,
which is the property used by the test case.

Differential revision: https://reviews.llvm.org/D83728
2020-07-14 08:45:34 -07:00
Sam McCall 50a5fa8b9b [clangd] Add missing link dep after 8eb8c92eb4 2020-07-14 17:03:45 +02:00
Sam McCall ff616f74c3 [clangd] Cache config files for 5 seconds, without revalidating with stat.
Summary:
This is motivated by:
 - code completion: nice to do no i/o on the request path
 - background index: deciding whether to enqueue each file would stat the config
   file thousands of times in quick succession.

Currently it's applied uniformly to all requests though.

This gives up on performing stat() outside the lock, all this achieves is
letting multiple threads stat concurrently (and thus finish without contention
for nonexistent files).
The ability to finish without IO (just mutex lock + integer check) should
outweigh this, and is less sensitive to platform IO characteristics.

Reviewers: kadircet

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83755
2020-07-14 17:00:41 +02:00
Sanjay Patel e6c016420c [ValueTracking] fix library to intrinsic mapping to respect 'nobuiltin' attribute
This is another problem raised in:
http://bugs.llvm.org/PR46627
2020-07-14 10:04:24 -04:00
Sanjay Patel 9300de4d1c [InstSimplify] add test with nobuiltin attribute (PR46627); NFC 2020-07-14 10:04:24 -04:00
Sam McCall 6c16fbd0ac [clangd] Config: CompileFlags.Remove
Summary: While here, add documentation to CompileFlags and CompileFlags.Add.

Reviewers: hokein

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83705
2020-07-14 15:56:44 +02:00
Simon Tatham 86d362f489 [utils] New script `check_ninja_deps.py`
Summary:
This can be run after a ninja-based build, and analyzes the ninja
build files and dependency database to spot any missing dependencies
in the build scripts.

I wrote it in the course of investigating D82659, and it seems likely
to be useful again.

Reviewers: thakis, chandlerc, theraven

Reviewed By: thakis

Subscribers: riccibruno, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83032
2020-07-14 14:54:08 +01:00
Louis Dionne efa40eb194 [libc++] Use a proper CMake target to represent libc++ headers
Instead of having complex logic around how to include the libc++ headers
and __config_site, handle that by defining cxx-headers as an INTERFACE
library and linking against it. After this patch, linking against cxx-headers
is sufficient to get the right __config_site include and include paths
for libc++.

Differential Revision: https://reviews.llvm.org/D82702
2020-07-14 09:52:58 -04:00
Jacques Pienaar 3ae43a580e [ods] Enable getting forward decls allow
Summary: Currently forward decls are included with all the op classes. But there are cases (say when splitting up headers) where one wants the forward decls but not all the classes. Add an option to enable this. This does not change any current behavior (some further refactoring is probably due here).

Differential Revision: https://reviews.llvm.org/D83727
2020-07-14 06:52:32 -07:00
Dmitri Gribenko 8978032a17 Fix test for the hasExternalFormalLinkage matcher
Summary:
Names of local variables have no linkage (see C++20 [basic.link] p8).

Names of variables in unnamed namespace have internal linkage (see C++20
[basic.link] p4).

Reviewers: aaron.ballman, rsmith, ymandel

Reviewed By: ymandel

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D83700
2020-07-14 15:44:53 +02:00
Sam McCall 8eb8c92eb4 [clangd] Add library to semantically strip flags by name.
Summary:
This is designed for tweaking compile commands by specifying flags to add/remove
in a config file. Something like:
  CompileFlags: { Remove: -fcolor-diagnostics }

Having users tweak raw argv (e.g. with a regex) is going to end in tears: bugs
around clang-cl, xclang, aliases, joined-vs-separate args etc are inevitable.

This isn't in tooling because of the performance choices: build a big table
up-front to make subsequent actions fast. Maybe it should be though.

Reviewers: adamcz, hokein

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D81958
2020-07-14 15:41:46 +02:00
Jay Foad 8a24208977 [AMDGPU] Simplify AMDGPUSubtarget::getWavesPerEU. NFC. 2020-07-14 14:20:02 +01:00
Mott, Jeffrey T d083adb068 Prohibit use of _ExtInt in atomic intrinsic
The _ExtInt type allows custom width integers, but the atomic memory
access's operand must have a power-of-two size. _ExtInts with
non-power-of-two size should not be allowed for atomic intrinsic.

Before this change:

$ cat test.c

typedef unsigned _ExtInt(42) dtype;
void verify_binary_op_nand(dtype* pval1, dtype val2)
{    __sync_nand_and_fetch(pval1, val2); }

$ clang test.c

clang-11:
/home/ubuntu/llvm_workspace/llvm/clang/lib/CodeGen/CGBuiltin.cpp:117:
llvm::Value*
EmitToInt(clang::CodeGen::CodeGenFunction&, llvm::Value*,
clang::QualType, llvm::IntegerType*): Assertion `V->getType() ==
IntType' failed.
PLEASE submit a bug report to https://bugs.llvm.org/ and include the
crash backtrace, preprocessed source, and associated run script.

After this change:

$ clang test.c

test.c:3:30: error: Atomic memory operand must have a power-of-two size
{    __sync_nand_and_fetch(pval1, val2); }
^

List of the atomic intrinsics that have this
problem:

__sync_fetch_and_add
__sync_fetch_and_sub
__sync_fetch_and_or
__sync_fetch_and_and
__sync_fetch_and_xor
__sync_fetch_and_nand
__sync_nand_and_fetch
__sync_and_and_fetch
__sync_add_and_fetch
__sync_sub_and_fetch
__sync_or_and_fetch
__sync_xor_and_fetch
__sync_fetch_and_min
__sync_fetch_and_max
__sync_fetch_and_umin
__sync_fetch_and_umax
__sync_val_compare_and_swap
__sync_bool_compare_and_swap

Differential Revision: https://reviews.llvm.org/D83340
2020-07-14 06:11:04 -07:00
Roger Ferrer Ibanez 0cbdd2a82a [RISCV] Fix isStoreToStackSlot
Because of the layout of stores (that don't have a destination operand)
this check is exactly the same as the one in
RISCVInstrInfo::isLoadFromStackSlot.

Differential Revision: https://reviews.llvm.org/D81805
2020-07-14 12:36:42 +00:00
Roger Ferrer Ibanez c1d021e2cc [NFC][RISCV] Test for D81805
New test to show the changes after D81805 is committed.

Differential Revision: https://reviews.llvm.org/D83750
2020-07-14 12:35:31 +00:00
Sourabh Singh Tomar 3d0b76022d [flang][OpenMP] upstream OpenMP lowering
Summary:
This patch implements lowering of OpenMP barrier construct from
pft to OpenMPDialect.

Patch is carved out of following merged PR's from fir-dev branch
of https://github.com/flang-compiler/f18-llvm-project/

PR's:
https://github.com/flang-compiler/f18-llvm-project/pull/248
https://github.com/flang-compiler/f18-llvm-project/pull/251

Unfortunately primary tool `bbc` for functional validation is not
yet upstreamed. So this patch includes a unittest for lowering
`!OMP barrier` construct.

Some part of the these PR's still remains downstream(functional test
and dialect registration to legalizer) for obvious reasons.
Will upstream them when the dependencies are upstreamed.

Reviewed By: schweitz, kiranchandramohan

Differential Revision: https://reviews.llvm.org/D83659
2020-07-14 18:01:15 +05:30
serge-sans-paille 1cd1c1d62e Revert "[SCEV][IndVarSimplify] insert point should not be block front."
This reverts commit f1efb8bb4b.

Reverted because it doesn't correctly update the pass return status, see

http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-debian/builds/9441/steps/test-check-all/logs/FAIL%3A%20LLVM%3A%3Awiden-i32-i8ptr.ll
2020-07-14 14:24:26 +02:00
Raphael Isemann 6f51ceea1f [lldb] Refactor character printing in DumpDataExtractor
Summary: Just unifying all that copy-pasted code.

Reviewers: JDevlieghere

Reviewed By: JDevlieghere

Differential Revision: https://reviews.llvm.org/D83662
2020-07-14 14:22:03 +02:00
Georgii Rymar 90e34b563a [yaml2obj] - Refine handling of the NoHeaders key.
Imagine we have an YAML description for some object and we want to
produce 2 outputs: with and without the section header.
A natural way to do it would look like:

```
--- !ELF
FileHeader:
  Class:   ELFCLASS64
  Data:    ELFDATA2LSB
  Type:    ET_REL
  Machine: EM_X86_64
Sections:
...
SectionHeaderTable:
  NoHeaders: [[NOHEADERS]]

```
But currently, we do not distinguish between no `NoHeaders` key case
and `NoHeaders == false`. Because of this we can't simply specify
`NOHEADERS = false`, as tool starts to complain.

With this patch the behavior changed. When we have:

```
SectionHeaderTable:
  NoHeaders: false

```
it is the same as we have no `SectionHeaderTable` at all.
(`NoHeaders` key still can't be used with `Sections/Excluded` keys)

Differential revision: https://reviews.llvm.org/D83672
2020-07-14 15:09:06 +03:00
Sanjay Patel 34d35d4a42 [ValueTracking] fix miscompile in maxnum case of cannotBeOrderedLessThanZeroImpl (PR46627)
A miscompile with -0.0 is shown in:
http://bugs.llvm.org/PR46627

This is because maxnum(-0.0, +0.0) does not specify a fixed result:
http://llvm.org/docs/LangRef.html#llvm-maxnum-intrinsic

So we need to tighten the constraints for when it is ok to say the
result of maxnum is positive (including +0.0).

Differential Revision: https://reviews.llvm.org/D83601
2020-07-14 08:08:09 -04:00
Sanjay Patel 9cc669d22d [InstCombine][InstSimplify] add tests for sign of maxnum; NFC
More coverage for D83601.
2020-07-14 08:08:09 -04:00
Georgii Rymar 84a1bc7f2c [test/Object][llvm-objdump] - llvm-objdump: don't abort() when the e_phoff field is invalid and refine testing.
llvm-objdump currently calls report_fatal_error() when the e_phoff field is invalid.

This is tested by elf-invalid-phdr.test which has the following issues:
1) It uses a precompiled object.
2) it could be a part of invalid.test.
3) It tests the Object lib, but we have no separate test for llvm-objdump.

This patch addresses issues mentioned.

Differential revision: https://reviews.llvm.org/D83559
2020-07-14 14:45:18 +03:00
Georgii Rymar 7ef17638d5 [llvm-readobj] - Stop using unwrapOrError() for all program_headers() calls.
program_headers() returns the list of program headers. This change allows
to continue attempt of dumping when something is wrong with program headers.

Differential revision: https://reviews.llvm.org/D83554
2020-07-14 14:16:57 +03:00
Paul Walker 6e198aae1d [SelectionDAG] Prevent warnings when extracting fixed length vector from scalable.
ComputeNumSignBits and computeKnownBits both trigger "Scalable flag
may be dropped" warnings when a fixed length vector is extracted
from a scalable vector.  This patch assumes nothing about the
demanded elements thus matching the behaviour when extracting a
scalable vector from a scalable vector.

Differential Revision: https://reviews.llvm.org/D83642
2020-07-14 11:12:56 +00:00
Pavel Labath 3cdbacc464 [lldb/test] Avoid globbing in log file handling code
The glob expression for a test called "test" could match a log file for
a the test "test_foo". Instead of globbing, maintain an explicit list of
log files relevant to the current test.
2020-07-14 13:10:59 +02:00
Xing GUO b539f01221 [DWARFYAML] Add support for emitting value forms of strx, addrx, etc.
This patch adds support for emitting value forms of DW_FORM_strx,
DW_FORM_addrx, DW_FORM_loclistx and DW_FORM_rnglistx.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D83749
2020-07-14 19:10:15 +08:00
Rainer Orth f0e9b76c35 [compiler-rt][sanitizers] Fix GetPcSpBp determination of SP on 32-bit Solaris/x86
A dozen 32-bit `AddressSanitizer` testcases FAIL on the latest beta of Solaris 11.4/x86, e.g.
`AddressSanitizer-i386-sunos :: TestCases/null_deref.cpp` produces

  AddressSanitizer:DEADLYSIGNAL
  =================================================================
  ==29274==ERROR: AddressSanitizer: stack-overflow on address 0x00000028 (pc 0x08135efd bp 0xfeffdfd8 sp 0x00000000 T0)
      #0 0x8135efd in NullDeref(int*) /vol/llvm/src/llvm-project/dist/compiler-rt/test/asan/TestCases/null_deref.cpp:15:10
      #1 0x8135ea6 in main /vol/llvm/src/llvm-project/dist/compiler-rt/test/asan/TestCases/null_deref.cpp:21:3
      #2 0x8084b85 in _start (null_deref.cpp.tmp+0x8084b85)

   SUMMARY: AddressSanitizer: stack-overflow /vol/llvm/src/llvm-project/dist/compiler-rt/test/asan/TestCases/null_deref.cpp:15:10 in NullDeref(int*)
  ==29274==ABORTING

instead of the expected

  AddressSanitizer:DEADLYSIGNAL
  =================================================================
  ==29276==ERROR: AddressSanitizer: SEGV on unknown address 0x00000028 (pc 0x08135f1f bp 0xfeffdf48 sp 0xfeffdf40 T0)
  ==29276==The signal is caused by a WRITE memory access.
  ==29276==Hint: address points to the zero page.
      #0 0x8135f1f in NullDeref(int*) /vol/llvm/src/llvm-project/local/compiler-rt/test/asan/TestCases/null_deref.cpp:15:10
      #1 0x8135efa in main /vol/llvm/src/llvm-project/local/compiler-rt/test/asan/TestCases/null_deref.cpp:21:3
      #2 0x8084be5 in _start (null_deref.cpp.tmp+0x8084be5)

  AddressSanitizer can not provide additional info.
   SUMMARY: AddressSanitizer: SEGV /vol/llvm/src/llvm-project/local/compiler-rt/test/asan/TestCases/null_deref.cpp:15:10 in NullDeref(int*)
  ==29276==ABORTING

I managed to trace this to a change in `<sys/regset.h>`: previously the header would
primarily define the short register indices (like `UESP`). While they are required by the
i386 psABI, they are only required in `<ucontext.h>` and could previously leak into
unsuspecting user code, polluting the namespace and requiring elaborate workarounds
like that in `llvm/include/llvm/Support/Solaris/sys/regset.h`. The change fixed that by restricting
the definition of the short forms appropriately, at the same time defining all `REG_` prefixed
forms for compatiblity with other systems.  This exposed a bug in `compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp`, however:
Previously, the index for the user stack pointer would be hardcoded if `REG_ESP`
wasn't defined. Now with that definition present, it turned out that `REG_ESP` was the wrong index to use: the previous value 17 (and `REG_SP`) corresponds to `REG_UESP`
instead.

With that change, the failures are all gone.

Tested on `amd-pc-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D83664
2020-07-14 12:56:18 +02:00
Georgii Rymar 3001569323 [yaml2obj] - Add a syntax to override e_phoff, e_phentsize and e_phnum fields.
This adds `EPhOff`, `EPhEntSize` and `EPhNum` keys.
Will be useful for creating broken objects for testing llvm-readelf.

Differential revision: https://reviews.llvm.org/D83482
2020-07-14 13:16:19 +03:00
Sam Elliott 1d15bbb9d9 Revert "[RISCV] Avoid Splitting MBB in RISCVExpandPseudo"
This reverts commit 97106f9d80.

This is based on feedback from https://reviews.llvm.org/D82988#2147105
2020-07-14 11:15:01 +01:00
Sam Parker a5405a2f05 [NFC][ARM] Add SimplifyCFG tests 2020-07-14 11:10:11 +01:00
Frederik Gossen 1ee0d22f26 [MLIR][Standard] Erase redundant assertions `std.assert`
Differential Revision: https://reviews.llvm.org/D83118
2020-07-14 10:09:39 +00:00
Frederik Gossen bcedc4fa0a [MLIR][Standard] Add `assert` operation to the standard dialect
Differential Revision: https://reviews.llvm.org/D83117
2020-07-14 10:00:54 +00:00
Victor Campos dad1868772 [AArch64][AsmParser] Add rcpc support in .arch_extension
AArch64 does not support enabling rcpc via .arch_extension in assembly.
GCC, on the other hand, does.

This patch adds 'rcpc' as a valid value to .arch_extension handling.

Differential Revision: https://reviews.llvm.org/D83685
2020-07-14 10:57:11 +01:00
LLVM GN Syncbot 3ae9f5d179 [gn build] Port dd6faf13d8 2020-07-14 09:36:07 +00:00
Igor Kudrin ec9f0c7d4a [DebugInfo] Fix a possible crash when reading a malformed .debug_*lists section.
DWARFListTableHeader::length() handles the zero value of HeaderData.Length
in a special way, which makes the result different from the calculated
value of FullLength, which leads to triggering an assertion. The patch
moves the assertion a bit later when `FullLength` is already checked for
minimal allowed value.

Differential Revision: https://reviews.llvm.org/D82886
2020-07-14 16:35:17 +07:00
Igor Kudrin dd6faf13d8 [DebugInfo] Add unit tests for DWARFListTableHeader::length().
This adds unit tests to check the expected behavior of the method in
case the unit length field is truncated.

Differential Revision: https://reviews.llvm.org/D83673
2020-07-14 16:35:17 +07:00
Igor Kudrin c4fc26b4c0 [ELF] Do not leave undefined symbols (specified by -init and -fini) if they are defined in non-fetched archive members
After D69985, symbols for "-init" and "-fini" were unconditionally
marked as used even if they were just lazy symbols seen when scanning
archives. That resulted in exposing them in the symbol table of an
output file, as Undefined, which added unwanted dependencies. The patch
fixes the issue by checking the kind of the symbols before the marking.

Differential Revision: https://reviews.llvm.org/D83549
2020-07-14 16:35:17 +07:00
LLVM GN Syncbot 242a736a14 [gn build] Port c15e04ee5e 2020-07-14 09:31:18 +00:00
Rainer Orth 2d1fe0c372 [llvm][unittests] Fix ProgramEnvTest.TestExecuteAndWaitStatistics on Solaris
The new `LLVM-Unit :: Support/./SupportTests/ProgramEnvTest.TestExecuteAndWaitStatistics` test currently FAILs on Solaris:

  [ RUN      ] ProgramEnvTest.TestExecuteAndWaitStatistics
  /vol/llvm/src/llvm-project/local/llvm/unittests/Support/ProgramTest.cpp:360: Failure
  Expected: (ProcStat->PeakMemory) > (0U), actual: 0 vs 0
  [  FAILED  ] ProgramEnvTest.TestExecuteAndWaitStatistics (22 ms)

According to `llvm/lib/Support/Unix/Program.inc (llvm::sys::Wait)`, `PeakMemory`
corresponds to `struct rusage.ru_maxrss`.

However, Solaris `getrusage(3C)` documents

  NOTES
         The ru_maxrss, ru_ixrss, ru_idrss, and ru_isrss members of  the  rusage
         structure are set to 0 in this implementation.

Since changing the test to check for `PeakMemory >= 0` instead is pointless
and would generate a warning on targets where `ru_maxrss` is unsigned, this
patch removes the check.

Tested on `amd64-pc-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D83661
2020-07-14 11:29:47 +02:00
Oliver Stannard 57909b0a53 [llvm-objdump] Add entry_value and stack_value opcodes
Add the DW_OP_entry_value and DW_OP_stack_value opcodes to the DWARF
expression printer.

Differential revision: https://reviews.llvm.org/D74843
2020-07-14 10:24:59 +01:00
Oliver Stannard 1d7311e052 [llvm-objdump] Add simple memory expressions to variable display
Add the DW_OP_breg0..DW_OP_breg31 and DW_OP_bregx opcodes to the DWARF
expression printer.

Differential revision: https://reviews.llvm.org/D74841
2020-07-14 10:24:59 +01:00
Oliver Stannard c15e04ee5e [DebugInfo] Add unit test for compact expression printer
Add a unit test for the compact DWARF expression printer which will be
used by the llvm-objdump --debug-vars option.

Differential revision: https://reviews.llvm.org/D75250
2020-07-14 10:24:59 +01:00
Jay Foad 5ab2e14d31 [AMDGPU] Fix typos in performCtlz_CttzCombine()
Fix two obvious errors in the code and also update the test check.
Also add one test to catch the failure.

Patch by Ruiling Song!

Differential Revision: https://reviews.llvm.org/D83280
2020-07-14 10:18:18 +01:00
Sjoerd Meijer 959eaa50d6 [ARM][MVE] Only tail-fold integer add reductions
If a vector body has live-out values, it is probably a reduction, which needs a
final reduction step after the loop. MVE has a VADDV instruction to reduce
integer vectors, but doesn't have an equivalent one for float vectors. A
live-out value that is not recognised as reduction later in the optimisation
pipeline will result in the tail-predicated loop to be reverted to a
non-predicated loop and this is very expensive, i.e. it has a significant
performance impact, which is what we hope to avoid with fine tuning the ARM TTI
hook preferPredicateOverEpilogue implementation.

Differential Revision: https://reviews.llvm.org/D82953
2020-07-14 10:15:07 +01:00