Commit Graph

364077 Commits

Author SHA1 Message Date
Georgii Rymar 61152a71a1 Revert "[llvm-readobj/elf] - Refine the code for broken PT_DYNAMIC segment diagnostic."
This reverts commit 455d5a8a06.

It broke UBSan:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap-ubsan/builds/21386/steps/check-llvm%20ubsan/logs/stdio

/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/test/tools/llvm-readobj/ELF/malformed-pt-dynamic.test:62:10: error: WARN3: expected string not found in input
# WARN3: error: '[[FILE]]': Invalid data was encountered while parsing the file
         ^
<stdin>:2:1: note: scanning from here
/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/tools/llvm-readobj/ELFDumper.cpp:1956:46: runtime error: addition of unsigned offset to 0x0000020c5b30 overflowed to 0x0000020c5b2f
^
<stdin>:2:1: note: with "FILE" equal to "/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm_build_ubsan/test/tools/llvm-readobj/ELF/Output/malformed-pt-dynamic\\.test\\.tmp3"
/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/tools/llvm-readobj/ELFDumper.cpp:1956:46: runtime error: addition of unsigned offset to 0x0000020c5b30 overflowed to 0x0000020c5b2f
^
<stdin>:2:117: note: possible intended match here
/b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/tools/llvm-readobj/ELFDumper.cpp:1956:46: runtime error: addition of unsigned offset to 0x0000020c5b30 overflowed to 0x0000020c5b2f
                                                                                                                    ^
Input file: <stdin>
Check file: /b/sanitizer-x86_64-linux-bootstrap-ubsan/build/llvm-project/llvm/test/tools/llvm-readobj/ELF/malformed-pt-dynamic.test
2020-08-20 14:04:30 +03:00
Paul Walker 0015b8db8e [SVE] Add ISEL patterns for predicated shifts by an immediate.
For scalable vector shifts the prediacte is typically all active,
which gets selected to an unpredicated shift by immediate.  When
code generating for fixed length vectors the predicate is based
on the vector length and so additional patterns are required to
make use of SVE's predicated shift by immediate instructions.

Differential Revision: https://reviews.llvm.org/D86204
2020-08-20 11:47:20 +01:00
David Stenberg 8206257cb8 [GlobalOpt] Fix an incorrect Modified status
When removing a non-constant store to a global in
CleanupPointerRootUsers(), the GlobalOpt pass could incorrectly return
false.

This was caught using the check introduced by D80916.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D86149
2020-08-20 11:52:09 +02:00
David Stenberg 7a1029fd1e Reland "[LoopUnswitch] Fix incorrect Modified status"
Relanded since the buildbot issue was unrelated to this commit.

When hoisting simple values out from a loop, and an optsize attribute, a
convergent call, or an invoke instruction hindered the pass from
unswitching the loop, the pass would return an incorrect Modified
status.

This was caught using the check introduced by D80916.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D86085
2020-08-20 11:52:09 +02:00
Bjorn Pettersson b43235a76c [DebugInfo] Fix DwarfExpression::addConstantFP for float on big-endian
The byte swapping, when dealing with 4 byte (float) FP constants
in DwarfExpression::addConstantFP, added in commit ef8992b9f0
was not correct. It always performed byte swapping using an
uint64_t value. When dealing with 4 byte values the 4 interesting
bytes ended up in the big end of the uint64_t, but later we emitted
the 4 bytes at the little end. So we ended up with zeroes being
emitted and faulty debug information.

This patch simplifies things a bit, IMHO. Using the APInt
representation throughout the function, instead of looking at
the internal representation using getRawBytes and without using
reinterpret_cast etc. And using API.byteSwap() should result in
correct byte swapping independent of APInt being 4 or 8 bytes.

Differential Revision: https://reviews.llvm.org/D86272
2020-08-20 11:48:05 +02:00
Georgii Rymar 455d5a8a06 [llvm-readobj/elf] - Refine the code for broken PT_DYNAMIC segment diagnostic.
The code that reports "PT_DYNAMIC segment offset + size exceeds the size of the file"
has an issue: it is possible to bypass the validation by overflowing the size + offset result.

Differential revision: https://reviews.llvm.org/D85519
2020-08-20 12:28:34 +03:00
David Stenberg ca688ae497 Revert "[LoopUnswitch] Fix incorrect Modified status"
This reverts commit dfd447c220.

After I pushed this commit, llvm-sphinx-docs started failing, due to:

  Warning, treated as error:
  extension 'recommonmark' has no setup() function;
  is it really a Sphinx extension module?

I don't see how this commit may have caused that, but I'm still
reverting it since I don't know how to proceed with that
troubleshooting.
2020-08-20 11:14:23 +02:00
Evgeny Leviant d5b701b972 [ThinLTO] Import globals recursively
Differential revision: https://reviews.llvm.org/D73698
2020-08-20 12:13:43 +03:00
Sebastian Neubauer b8d1994778 [AMDGPU] Add A16/G16 to InstCombine
When sampling from images with coordinates that only have 16 bit
accuracy, convert the image intrinsic call to use a16 or g16.
This does only happen if the target hardware supports it.

An alternative would be to always apply this combination, independent of
the target hardware and extend 16 bit arguments to 32 bit arguments
during legalization. To me, this sounds like an unnecessary roundtrip
that could prevent some further InstCombine optimizations.

Differential Revision: https://reviews.llvm.org/D85887
2020-08-20 10:51:49 +02:00
Konstantin Schwarz 7497b861f4 [GlobalISel][IRTranslator] Support PHI instructions in landingpad blocks
The check for the landingpad instructions was overly restrictive. In optimimized builds PHI nodes can appear
before the landingpad instructions, resulting in a fallback to SelectionDAG.

This change relaxes the check to allow PHI nodes.

Reviewed By: arsenm

Differential Revision: https://reviews.llvm.org/D86141
2020-08-20 10:49:31 +02:00
Georgii Rymar a6436b0b3a [yaml2obj] - Make the 'Machine' key optional.
Currently we have to set 'Machine' to something in our
YAML descriptions. Usually we use 'EM_X86_64' for 64-bit targets
and 'EM_386' for 32-bit targets. At the same time, in fact, in most
cases our tests do not need a machine type and we can use
'EM_NONE'.

This is cleaner, because avoids the need of using a particular machine.

In this patch I've made the 'Machine' key optional (the default value,
when it is not specified is `EM_NONE`) and removed it (where possible)
from yaml2obj, obj2yaml and llvm-readobj tests.

There are few tests left where I decided not to remove it, because
I didn't want to touch CHECK lines or doing anything more complex
than a removing a "Machine: *" line and formatting lines around.

Differential revision: https://reviews.llvm.org/D86202
2020-08-20 11:40:51 +03:00
Bevin Hansson 44ebc2c8eb Refactor most of the fixed-point tests.
The tests were not written with update_cc_test_checks
in mind, which make them difficult to update. Fix this.

Also, some of the consteval tests were outright broken,
since the CHECK lines were wrong.

Other than this, the semantics of the tests are preserved.
2020-08-20 10:30:05 +02:00
Bevin Hansson f03b10f57e [IR] Add FixedPointBuilder.
This patch adds a convenience class for using FixedPointSemantics
to build fixed-point operations in IR.

RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-August/144025.html

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D85314
2020-08-20 10:29:57 +02:00
Bevin Hansson 1a995a0af3 [ADT] Move FixedPoint.h from Clang to LLVM.
This patch moves FixedPointSemantics and APFixedPoint
from Clang to LLVM ADT.

This will make it easier to use the fixed-point
classes in LLVM for constructing an IR builder for
fixed-point and for reusing the APFixedPoint class
for constant evaluation purposes.

RFC: http://lists.llvm.org/pipermail/llvm-dev/2020-August/144025.html

Reviewed By: leonardchan, rjmccall

Differential Revision: https://reviews.llvm.org/D85312
2020-08-20 10:29:45 +02:00
Bevin Hansson 1e7ec4842c [AST] Get field size in chars rather than bits in RecordLayoutBuilder.
In D79719, LayoutField was refactored to fetch the size of field
types in bits and then convert to chars, rather than fetching
them in chars directly. This is not ideal, since it makes the
calculations char size dependent, and breaks for sizes that
are not a multiple of the char size.

This patch changes it to use getTypeInfoInChars instead of
getTypeInfo.

Reviewed By: efriedma

Differential Revision: https://reviews.llvm.org/D85191
2020-08-20 10:29:29 +02:00
Arjun P 33f574672f [MLIR] Redundancy detection for FlatAffineConstraints using Simplex
This patch adds the capability to perform constraint redundancy checks for `FlatAffineConstraints` using `Simplex`, via a new member function `FlatAffineConstraints::removeRedundantConstraints`. The pre-existing redundancy detection algorithm runs a full rational emptiness check for each inequality separately for checking redundancy. Leveraging the existing `Simplex` infrastructure, in this patch we have an algorithm for redundancy checks that can check each constraint by performing pivots on the tableau, which provides an alternative to running Fourier-Motzkin elimination for each constraint separately.

Differential Revision: https://reviews.llvm.org/D84935
2020-08-20 13:38:51 +05:30
dfukalov 33e2f69a24 [AMDGPU][LoopUnroll] Increase BB size to analyze for complete unroll.
The `UnrollMaxBlockToAnalyze` parameter is used at the stage when we have no
information about a loop body BB cost. In some cases, e.g. for simple loop
```
for(int i=0; i<32; ++i){
  D = Arr2[i*8 + C1];
  Arr1[i*64 + C2] += C3 * D;
  Arr1[i*64 + C2 + 2048] += C4 * D;
}

```
current default parameter value is not enough to run deeper cost analyze so the
loop is not completely unrolled.

Reviewed By: rampitec

Differential Revision: https://reviews.llvm.org/D86248
2020-08-20 10:41:47 +03:00
Petr Hosek d58fd4e521 [compiler-rt] Compile assembly files as ASM not C
It isn't very wise to pass an assembly file to the compiler and tell it to compile as a C file and hope that the compiler recognizes it as assembly instead.
Instead enable the ASM language and mark the files as being ASM.

[525/634] Building C object lib/tsan/CMakeFiles/clang_rt.tsan-aarch64.dir/rtl/tsan_rtl_aarch64.S.o
FAILED: lib/tsan/CMakeFiles/clang_rt.tsan-aarch64.dir/rtl/tsan_rtl_aarch64.S.o
/opt/tooling/drive/host/bin/clang --target=aarch64-linux-gnu -I/opt/tooling/drive/llvm/compiler-rt/lib/tsan/.. -isystem /opt/tooling/drive/toolchain/opt/drive/toolchain/include -x c -Wall -Wno-unused-parameter -fno-lto -fPIC -fno-builtin -fno-exceptions -fomit-frame-pointer -funwind-tables -fno-stack-protector -fno-sanitize=safe-stack -fvisibility=hidden -fno-lto -O3 -gline-tables-only -Wno-gnu -Wno-variadic-macros -Wno-c99-extensions -Wno-non-virtual-dtor -fPIE -fno-rtti -Wframe-larger-than=530 -Wglobal-constructors --sysroot=. -MD -MT lib/tsan/CMakeFiles/clang_rt.tsan-aarch64.dir/rtl/tsan_rtl_aarch64.S.o -MF lib/tsan/CMakeFiles/clang_rt.tsan-aarch64.dir/rtl/tsan_rtl_aarch64.S.o.d -o lib/tsan/CMakeFiles/clang_rt.tsan-aarch64.dir/rtl/tsan_rtl_aarch64.S.o -c /opt/tooling/drive/llvm/compiler-rt/lib/tsan/rtl/tsan_rtl_aarch64.S
/opt/tooling/drive/llvm/compiler-rt/lib/tsan/rtl/tsan_rtl_aarch64.S:29:1: error: expected identifier or '('
.section .text
^
1 error generated.

Fixed Clang not being passed as the assembly compiler for compiler-rt runtime build.

Patch By: tambre

Differential Revision: https://reviews.llvm.org/D85706
2020-08-20 00:34:59 -07:00
Yvan Roux 0459f29e8b [ARM][MachineOutliner] Add default mode.
Use the stack to save and restore the link register when there is no
available register to do it.

Differential Revision: https://reviews.llvm.org/D76069
2020-08-20 09:25:33 +02:00
David Stenberg dfd447c220 [LoopUnswitch] Fix incorrect Modified status
When hoisting simple values out from a loop, and an optsize attribute, a
convergent call, or an invoke instruction hindered the pass from
unswitching the loop, the pass would return an incorrect Modified
status.

This was caught using the check introduced by D80916.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D86085
2020-08-20 09:04:16 +02:00
Johannes Doerfert 012819f301 [Attributor][FIX] Update the call graph properly when internalizing functions
The internal version is now part of the SCC, make sure to perform this
update.
2020-08-20 01:44:58 -05:00
Johannes Doerfert 3edea15f9a [Attributor] Simplify comparison against constant null pointer
Comparison against null is a common pattern that usually is followed by
error handling code and the likes. We now use AANonNull to simplify
these comparisons optimistically in order to make more code dead early
on.

Reviewed By: uenoku

Differential Revision: https://reviews.llvm.org/D86145
2020-08-20 01:44:58 -05:00
Johannes Doerfert d01ad217ba [Attributor][FIX] Do not use cyclic arguments for `nonnull`
`AADereferenceable::getAssumedDereferenceableBytes()` is actually
deducing `dereferenceable_or_null`. We should not use that information
to deduce `nonnull`, since it doesn't imply `nonnull`.
2020-08-20 01:44:58 -05:00
Johannes Doerfert a49dae0e38 [Attributor][AAIsDead][NFC] Skip uninteresting instructions early 2020-08-20 01:44:58 -05:00
Johannes Doerfert 5d6602b555 [Attributor][NFC] Improve the depgraph test to make differences clear 2020-08-20 01:44:58 -05:00
Johannes Doerfert 08f33756e6 [Attributor][NFC] Extract functionality into own member 2020-08-20 01:44:58 -05:00
Fangrui Song ac46bc35e9 [ELF][test] Fix some llvm-objdump RUN lines which don't actually test anything 2020-08-19 22:49:04 -07:00
Qiu Chaofan 131b3b9ed4 [PowerPC] Support constrained scalar fptosi/fptoui
This patch adds support for constrained scalar fp to int operations on
PowerPC. Besides, this fixes the FP exception bit of quad-precision
convert & truncate instructions.

Reviewed By: steven.zhang, uweigand

Differential Revision: https://reviews.llvm.org/D81537
2020-08-20 13:29:43 +08:00
Johannes Doerfert 2f38c755ba Revert "[IR] Intrinsics default attributes and opt-out flag"
This commit introduced a non-trivial compile time regression that needs
to be addressed: https://reviews.llvm.org/D70365#2227627
Given that it is unclear how long that will take, I'll revert it for
now.

This reverts commit eedf18fc1f.
2020-08-20 00:25:32 -05:00
Johannes Doerfert 1de70a724e Revert "[OpenMPOpt] ICV tracking for calls"
This commits breaks certain OpenMP codes (on power) because it expanded
the Attributor scope without telling the Attributor about the SCC
extend. See: https://reviews.llvm.org/D85544#2227611

This reverts commit b0b32e6490.
2020-08-20 00:00:35 -05:00
Shilei Tian 0289696751 [OpenMP] Introduce target memory manager
Target memory manager is introduced in this patch which aims to manage target
memory such that they will not be freed immediately when they are not used
because the overhead of memory allocation and free is very large. For CUDA
device, cuMemFree even blocks the context switch on device which affects
concurrent kernel execution.

The memory manager can be taken as a memory pool. It divides the pool into
multiple buckets according to the size such that memory allocation/free
distributed to different buckets will not affect each other.

In this version, we use the exact-equality policy to find a free buffer. This
is an open question: will best-fit work better here? IMO, best-fit is not good
for target memory management because computation on GPU usually requires GBs of
data. Best-fit might lead to a serious waste. For example, there is a free
buffer of size 1960MB, and now we need a buffer of size 1200MB. If best-fit,
the free buffer will be returned, leading to a 760MB waste.

The allocation will happen when there is no free memory left, and the memory
free on device will take place in the following two cases:
1. The program ends. Obviously. However, there is a little problem that plugin
library is destroyed before the memory manager is destroyed, leading to a fact
that the call to target plugin will not succeed.
2. Device is out of memory when we request a new memory. The manager will walk
through all free buffers from the bucket with largest base size, pick up one
buffer, free it, and try to allocate immediately. If it succeeds, it will
return right away rather than freeing all buffers in free list.

Update:
A threshold (8KB by default) is set such that users could control what size of memory
will be managed by the manager. It can also be configured by an environment variable
`LIBOMPTARGET_MEMORY_MANAGER_THRESHOLD`.

Reviewed By: jdoerfert, ye-luo, JonChesterfield

Differential Revision: https://reviews.llvm.org/D81054
2020-08-19 23:12:23 -04:00
Zi Xuan Wu (Zeson) fc18e48320 [NFC] It's a test commit, which updates CREDITS.TXT 2020-08-20 11:04:08 +08:00
Tony b690c1157e [AMDGPU] Correct DWARF register defintions
- Rename AMDGPU SCC DWARF register to STATUS since the scalar
  condition code is a bit within the STATUS register.

- Correct bit size of the VCC_64 register to 64 which is the size in
  wave64 mode.

Differential Revision: https://reviews.llvm.org/D86259
2020-08-20 01:15:04 +00:00
Jonas Devlieghere a6eb70c052 [lldb] Return empty string from getExtraMakeArgs when not implemented
No return statement means the method returns None which breaks a list
comprehension down the line that expects a str instance.
2020-08-19 17:52:50 -07:00
Craig Topper 8750d54cea [X86][AutoUpgrade] Simplify string management in UpgradeDataLayoutString a bit. NFCI
We don't need a std::string for a literal string, we can use a
StringRef.

The addition of StringRefs produces a Twine that we can just call
str() without converting to a SmallString ourselves. Twine will
do that internally.
2020-08-19 17:48:11 -07:00
Rahul Joshi 9c7b0c4aa5 [MLIR] Add PatternRewriter::mergeBlockBefore() to merge a block in the middle of another block.
- This utility to merge a block anywhere into another one can help inline single
  block regions into other blocks.
- Modified patterns test to use the new function.

Differential Revision: https://reviews.llvm.org/D86251
2020-08-19 16:24:59 -07:00
Craig Topper 724f570ad2 [X86] Add support 'tune' in target attribute
This adds parsing and codegen support for tune in target attribute.

I've implemented this so that arch in the target attribute implicitly disables tune from the command line. I'm not sure what gcc does here. But since -march implies -mtune. I assume 'arch' in the target attribute implies tune in the target attribute.

Differential Revision: https://reviews.llvm.org/D86187
2020-08-19 15:58:19 -07:00
Craig Topper 4a36711439 [X86] Add mtune command line test cases that should have gone with 4cbceb74bb 2020-08-19 15:58:06 -07:00
Matt Arsenault 31adc28d24 GlobalISel: Implement fewerElementsVector for G_CONCAT_VECTORS sources
This fixes <6 x s16> = G_CONCAT_VECTORS from <3 x s16> handling.
2020-08-19 18:53:24 -04:00
Richard Smith c1c1bed5d0 [c++14] Implement missed piece of N3323: use "converted constant" rules
for array bounds, not "integer constant" rules.

For an array bound of class type, this causes us to perform an implicit
conversion to size_t, instead of looking for a unique conversion to
integral or unscoped enumeration type. This affects which cases are
valid when a class has multiple implicit conversion functions to
different types.
2020-08-19 15:45:51 -07:00
Richard Smith 6f33936719 Explain why the array bound is non-constant in VLA diagnostics.
In passing, also use a more precise diagnostic to explain why an
expression is not an ICE if it's not of integral type.
2020-08-19 15:45:51 -07:00
Jonas Devlieghere 09ca3f41bb [lldb] Update TestSimulatorPlatform.py to set ARCH_CFLAGS instead of TRIPLE
I move the triple (de)composition logic into the builder in e5d08fcbac
but this test is relying on Make to construct the set the ARCH,
ARCH_CFLAGS and SDKROOT based on the given TRIPLE. This patch updates
the test to pass these variables directly.

Differential revision: https://reviews.llvm.org/D86244
2020-08-19 15:42:44 -07:00
Med Ismail Bennani 868b45b5b3 [lldb/interpreter] Add REPL-specific init file
This patch adds the infrastructure to have language specific REPL init
files. It's the foundation work to a following patch that will introduce
Swift REPL init file.

When lldb is launched with the `--repl` option, it will look for a REPL
init file in the home directory and source it. This overrides the
default `~/.lldbinit`, which content might make the REPL behave
unexpectedly. If the REPL init file doesn't exists, lldb will fall back
to the default init file.

rdar://65836048

Differential Revision: https://reviews.llvm.org/D86242

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>
2020-08-20 00:36:32 +02:00
Dokyung Song 428bebaf10 [libFuzzer] Fix value-profile-load test.
The behavior of the CrossOver mutator has changed with
bb54bcf849. This seems to affect the
value-profile-load test on Darwin. This patch provides a wider margin for
determining success of the value-profile-load test, by testing the targeted
functionality (i.e., GEP index value profile) more directly and faster. To this
end, LoadTest.cpp now uses a narrower condition (Size != 8) for initial pruning
of inputs, effectively preventing libFuzzer from generating inputs longer than
necessary and spending time on mutating such long inputs in the corpus - a
functionality not meant to be tested by this specific test.

Previously, on x86/Linux, it required 6,597,751 execs with -use_value_profile=1
and 19,605,575 execs with -use_value_profile=0 to hit the crash. With this
patch, the test passes with 174,493 execs, providing a wider margin from the
given trials of 10,000,000. Note that, without the value profile (i.e.,
-use_value_profile=0), the test wouldn't pass as it still requires 19,605,575
execs to hit the crash.

Differential Revision: https://reviews.llvm.org/D86247
2020-08-19 22:14:43 +00:00
Matt Morehouse 4deda57106 [DFSan] Handle mmap() calls before interceptors are installed.
InitializeInterceptors() calls dlsym(), which calls calloc().  Depending
on the allocator implementation, calloc() may invoke mmap(), which
results in a segfault since REAL(mmap) is still being resolved.

We fix this by doing a direct syscall if interceptors haven't been fully
resolved yet.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D86168
2020-08-19 15:07:41 -07:00
Siva Chandra Reddy e2645488ca [libc][obvious] Fix x86 long double conversion to integer.
Fixes incorrectly constructed ceill tests.
2020-08-19 14:48:55 -07:00
Francesco Petrogalli dac0b1d330 [llvm] Add default constructor of `llvm::ElementCount`.
This patch prevents failures like those reported in
http://lab.llvm.org:8011/builders/llvm-clang-lld-x86_64-scei-ps4-windows10pro-fast/builds/34173.

We have enabled the default constructor for
`llvm::ElementCount` to make sure the code compiles on Windows.

Reviewed By: ormris

Differential Revision: https://reviews.llvm.org/D86240
2020-08-19 21:39:24 +00:00
Petr Hosek 1ed1e16ab8 [CMake] Fix an issue where get_system_libname creates an empty regex capture on windows
Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=1119478

Patch By: haampie

Differential Revision: https://reviews.llvm.org/D86245
2020-08-19 14:33:52 -07:00
Kyungwoo Lee 7a028fe702 Force Remove Attribute
-force-attribute adds an attribute to function via command-line.
However, there was no counter-part to remove an attribute.  This patch
adds -force-remove-attribute that removes an attribute from function.

Differential Revision: https://reviews.llvm.org/D85586
2020-08-19 17:30:13 -04:00
Sanjay Patel 6f3511a01a [ValueTracking] define/use max recursion depth in header
There's a potential motivating case to increase this limit in PR47191:
http://bugs.llvm.org/PR47191

But first we should make it less hacky. The limit in InstCombine is directly tied
to this value because an increase there can cause asserts in the underlying value
tracking calls if not changed together. The usage in VectorUtils is independent,
but the comment suggests that we should use the same value unless there's a known
reason to diverge. There are similar limits in codegen analysis, but I think we
should leave those independent in case we intentionally want the optimization
power/cost to be different there.

Differential Revision: https://reviews.llvm.org/D86113
2020-08-19 16:56:59 -04:00