Nirav Dave [Wed, 13 Mar 2019 17:07:09 +0000 (17:07 +0000)]
[DAGCombiner] If a TokenFactor would be merged into its user, consider the user later.
Summary:
A number of optimizations are inhibited by single-use TokenFactors not
being merged into the TokenFactor using it. This makes we consider if
we can do the merge immediately.
Most tests changes here are due to the change in visitation causing
minor reorderings and associated reassociation of paired memory
operations.
CodeGen tests with non-reordering changes:
X86/aligned-variadic.ll -- memory-based add folded into stored leaq
value.
X86/constant-combiners.ll -- Optimizes out overlap between stores.
X86/pr40631_deadstore_elision -- folds constant byte store into
preceding quad word constant store.
Alex Bradbury [Wed, 13 Mar 2019 16:33:45 +0000 (16:33 +0000)]
[RISCV] Only mark fp as reserved if the function has a dedicated frame pointer
This follows similar logic in the ARM and Mips backends, and allows the free
use of s0 in functions without a dedicated frame pointer. The changes in
callee-saved-gprs.ll most clearly show the effect of this patch.
Alex Bradbury [Wed, 13 Mar 2019 16:14:16 +0000 (16:14 +0000)]
[RISCV] Add tests for callee-saved GPRs, FPR32s, and FPR64s
Note that s0 need not be marked reserved if the frame pointer isn't used. For
the ILP32 and LP64 soft float ABIS that are currently support, all FPRs are
always considered temporaries.
Sanjay Patel [Wed, 13 Mar 2019 14:49:52 +0000 (14:49 +0000)]
[x86] limit extractelement of setcc to pre-legalization
A fuzzer found the crasher:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=13700
The bug was introduced recently here:
rL355741
This is the quick fix. If we need to do this transform
later, then we'd have to extend/truncate the vector setcc
element type to the scalar setcc type (i8).
Simon Atanasyan [Wed, 13 Mar 2019 13:09:30 +0000 (13:09 +0000)]
[mips] Map SW instruction to its microMIPS R6 variant
To provide mapping between standard and microMIPS R6 variants of the
`sw` command we have to rename SWSP_xxx commands from "sw" to "swsp".
Otherwise `tablegen` starts to show the error `Multiple matches found
for `SW'`. After that to restore printing SWSP command as `sw`, I add
an appropriate `MipsInstAlias` instance.
We also need to implement "size reduction" for microMIPS R6. But this
task is for separate patch. After that the `micromips-lwsp-swsp.ll` test
case will be extended.
Simon Pilgrim [Wed, 13 Mar 2019 12:20:39 +0000 (12:20 +0000)]
[X86][AVX] lowerShuffleAsBroadcast - improve load folding by avoiding bitcasts
AVX1 broadcasts were failing as we were adding bitcasts that caused MayFoldLoad's hasOneUse to return false.
This patch stops introducing bitcasts so early and also replaces the broadcast index scaling through bitcasts (which can't succeed in some cases) to instead just keep track of the bitoffset which can be converted back to the broadcast index later on.
Jeremy Morse [Wed, 13 Mar 2019 11:43:13 +0000 (11:43 +0000)]
[DebugInfo][Docs] Document how dbg.value intrinsics are interpreted in optimized code
This patch adds a section, ``Object lifetime in optimized code'', that
documents how such intrinsics are supposed to be handled. It sets out some of
the principles of how they specify variable locations, and how long those
locations are valid for.
This patch also documents one of the objectives behind the variable-location
design, that we should never allow the debugger to observe a state of the
program that would not have appeared without optimization.
Simon Pilgrim [Wed, 13 Mar 2019 11:08:57 +0000 (11:08 +0000)]
[DAG] Move integer setcc %x, %x folding into FoldSetCC
First step towards PR40800 - I intend to move the float case in a separate future patch.
I had to tweak the (overly reduced) thumb2 test and the x86 widening test change is annoying (no longer rematerializable) but we should address this separately.
Simon Atanasyan [Wed, 13 Mar 2019 11:04:38 +0000 (11:04 +0000)]
[MIPS][microMIPS] Fix PseudoMTLOHI_MM matching and expansion
On micromips MipsMTLOHI is always matched to PseudoMTLOHI_DSP regardless
of +dsp argument. This patch checks is HasDSP predicate is present for
PseudoMTLOHI_DSP so PseudoMTLOHI_MM can be matched when appropriate.
Add expansion of PseudoMTLOHI_MM instruction into a mtlo/mthi pair.
Jonas Hahnfeld [Wed, 13 Mar 2019 10:38:17 +0000 (10:38 +0000)]
[ELF] Fix GCC8 warnings about "fall through", NFCI
Add break statements in Object/ELF.cpp since the code should consider the
generic tags for Hexagon, MIPS, and PPC. Add a test (copied from llvm-readobj)
to show that this works correctly (earlier versions of this patch would have
asserted).
The warnings in X86ELFObjectWriter.cpp are actually false-positives since
the nested switch() handles all possible values and returns in all cases.
Make this explicit by adding llvm_unreachable's.
Jonas Hahnfeld [Wed, 13 Mar 2019 10:37:56 +0000 (10:37 +0000)]
[Support] Treat truncation of fullpath as error
If the concatenation of arguments dir and bin has at least PATH_MAX
characters the call to snprintf will truncate. The result will usually
not exist, but if it does it's actually incorrect to return that the
path exists.
(Motivated by GCC compiler warning about format truncation.)
Heejin Ahn [Wed, 13 Mar 2019 00:37:31 +0000 (00:37 +0000)]
[WebAssembly] Place 'try' and 'catch' correctly wrt EH_LABELs
Summary:
After instruction selection phase, possibly-throwing calls, which were
previously invoke, are wrapped in `EH_LABEL` instructions. For example:
```
EH_LABEL <mcsymbol .Ltmp0>
CALL_VOID @foo ...
EH_LABEL <mcsymbol .Ltmp1>
```
`EH_LABEL` is placed also in the beginning of EH pads:
```
bb.1 (landing-pad):
EH_LABEL <mcsymbol .Ltmp2>
...
```
And we'd like to maintian this relationship, so when we place a `try`,
```
TRY ...
EH_LABEL <mcsymbol .Ltmp0>
CALL_VOID @foo ...
EH_LABEL <mcsymbol .Ltmp1>
```
When we place a `catch`,
```
bb.1 (landing-pad):
EH_LABEL <mcsymbol .Ltmp2>
%0:except_ref = CATCH ...
...
```
Previously we didn't treat EH_LABELs specially, so `try` was placed
right before a call, and `catch` was placed in the beginning of an EH
pad.
Hubert Tong [Wed, 13 Mar 2019 00:12:43 +0000 (00:12 +0000)]
Use AIX version detection at LLVM run-time
Summary:
AIX compilers define macros based on the version of the operating
system.
This patch implements updating of versionless AIX triples to include the
host AIX version. Also, the host triple detection in the build system is
adjusted to strip the AIX version information so that the run-time
detection is preferred.
Craig Topper [Tue, 12 Mar 2019 23:48:07 +0000 (23:48 +0000)]
[X86] Add ImmArg markings to intrinsics.
Remove test cases that checked for not crashing when immediate operands were passed not an immediate. These are now considered ill-formed in IR.
This was done by manually scanning the intrinsic file for llvm_i32_ty and llvm_i8_ty which are the predominant types we use for immediates. Most of them are on vector intrinsics. I might have missed some other intrinsics.
Jason Liu [Tue, 12 Mar 2019 22:01:10 +0000 (22:01 +0000)]
Add XCOFF triple object format type for AIX
This patch adds an XCOFF triple object format type into LLVM.
This XCOFF triple object file type will be used later by object file and assembly generation for the AIX platform.
Reland "[Remarks] Add -foptimization-record-passes to filter remark emission"
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Philip Reames [Tue, 12 Mar 2019 21:05:31 +0000 (21:05 +0000)]
For faulting ops, include a comment w/the fault destination
A faulting_op is one that has specified behavior when a fault occurs, generally redirecting control flow to another location. This change just adds a comment to the assembly output which makes it both human readable, and machine checkable w/o having to parse the FaultMap section. This is used to split a test file into two parts, so that I can (in a near future commit) easily extend the test file to demonstrate another case.
Matt Arsenault [Tue, 12 Mar 2019 21:02:54 +0000 (21:02 +0000)]
IR: Add immarg attribute
This indicates an intrinsic parameter is required to be a constant,
and should not be replaced with a non-constant value.
Add the attribute to all AMDGPU and generic intrinsics that comments
indicate it should apply to. I scanned other target intrinsics, but I
don't see any obvious comments indicating which arguments are intended
to be only immediates.
This breaks one questionable testcase for the autoupgrade. I'm unclear
on whether the autoupgrade is supposed to really handle declarations
which were never valid. The verifier fails because the attributes now
refer to a parameter past the end of the argument list.
Matt Arsenault [Tue, 12 Mar 2019 20:42:12 +0000 (20:42 +0000)]
MIR: Stop reinitializing target information for every use
Every time a physical register reference was parsed, this would
initialize a string map for every register in in target, and discard
it for the next. The same applies for the other fields initialized
from target information.
Follow along with how the function state is tracked, and add a new
tracking class for target information.
The string->register class/register bank for some reason were kept
separately, so track them in the same place.
[Remarks] Add -foptimization-record-passes to filter remark emission
Currently we have -Rpass for filtering the remarks that are displayed as
diagnostics, but when using -fsave-optimization-record, there is no way
to filter the remarks while generating them.
This adds support for filtering remarks by passes using a regex.
Ex: `clang -fsave-optimization-record -foptimization-record-passes=inline`
will only emit the remarks coming from the pass `inline`.
This adds:
* `-fsave-optimization-record` to the driver
* `-opt-record-passes` to cc1
* `-lto-pass-remarks-filter` to the LTOCodeGenerator
* `--opt-remarks-passes` to lld
* `-pass-remarks-filter` to llc, opt, llvm-lto, llvm-lto2
* `-opt-remarks-passes` to gold-plugin
Philip Reames [Tue, 12 Mar 2019 20:15:05 +0000 (20:15 +0000)]
[SROA] Fix a crash when trying to convert a memset to an non-integral pointer type
The included test case currently crashes on tip of tree. Rather than adding a bailout, I chose to restructure the code so that the existing helper function could be used. Given that, the majority of the diff is NFC-ish, but the key difference is that canConvertValue returns false when only one side is a non-integral pointer.
Philip Reames [Tue, 12 Mar 2019 19:12:33 +0000 (19:12 +0000)]
[CodeGen] Add MMOs to statepoint nodes during SelectionDAG
The existing statepoint lowering code does something odd; it adds machine memory operands post instruction selection. This was copied from the stackmap/patchpoint implementation, but appears to be non-idiomatic.
This change is largely NFC. It moves the MMO creation logic into SelectionDAG building. It ends up not quite being NFC because the size of the stack slot is reflected in the MMO. The old code blindly used pointer size for the MMO size, which appears to have always been incorrect for larger values. It just happened nothing actually relied on the MMOs, so it worked out okay.
For context, I'm planning on removing the MOVolatile flag from these in a future commit, and then removing the MOStore flag from deopt spill slots in a separate one. Doing so is motivated by a small test case where we should be able to better schedule spill slots, but don't do so due to a memory use/def implied by the statepoint.
Teresa Johnson [Tue, 12 Mar 2019 18:28:05 +0000 (18:28 +0000)]
[SCEV] Use depth limit for trunc analysis
Summary:
This fixes an extremely long compile time caused by recursive analysis
of truncs, which were not previously subject to any depth limits unlike
some of the other ops. I decided to use the same control used for
sext/zext, since the routines analyzing these are sometimes mutually
recursive with the trunc analysis.
Craig Topper [Tue, 12 Mar 2019 18:20:25 +0000 (18:20 +0000)]
[SanitizerCoverage] Avoid splitting critical edges when destination is a basic block containing unreachable
This patch adds a new option to SplitAllCriticalEdges and uses it to avoid splitting critical edges when the destination basic block ends with unreachable. Otherwise if we split the critical edge, sanitizer coverage will instrument the new block that gets inserted for the split. But since this block itself shouldn't be reachable this is pointless. These basic blocks will stick around and generate assembly, but they don't end in sane control flow and might get placed at the end of the function. This makes it look like one function has code that flows into the next function.
This showed up while compiling the linux kernel with clang. The kernel has a tool called objtool that detected the code that appeared to flow from one function to the next. https://github.com/ClangBuiltLinux/linux/issues/351#issuecomment-461698884
James Henderson [Tue, 12 Mar 2019 17:00:25 +0000 (17:00 +0000)]
[yaml2obj]Allow explicit symbol indexes in relocations and emit error for bad names
Prior to this change, the "Symbol" field of a relocation would always be
assumed to be a symbol name, and if no such symbol existed, the
relocation would reference index 0. This confused me when I tried to use
a literal symbol index in the field: since "0x1" was not a known symbol
name, the symbol index was set as 0. This change falls back to treating
unknown symbol names as integers, and emits an error if the name is not
found and the string is not an integer.
Note that the Symbol field is optional, so if a relocation doesn't
reference a symbol, it shouldn't be specified. The new error required a
number of test updates.
Nikita Popov [Tue, 12 Mar 2019 16:57:25 +0000 (16:57 +0000)]
[SDAG] Expand pow2 mulo using shifts
Expand MULO with constant power of two operand into a shift. The
overflow is checked with (x << shift) >> shift == x, where the right
shift will be logical for umulo and arithmetic for smulo (with
exception for multiplications by signed_min).
Kristina Brooks [Tue, 12 Mar 2019 15:44:18 +0000 (15:44 +0000)]
[Docs] Add note about legacy PM to Ch4 of tutorial
Add a note about legacy FunctionPassManager to the LLVM tutorial.
It seems to confuse some people, worth adding a warning to the tutorial
to elaborate and suggest using `llvm::legacy::FunctionPassManager` for
now. Not a perfect solution but hopefully will avoid confusion
in the meantime.
James Henderson [Tue, 12 Mar 2019 15:42:38 +0000 (15:42 +0000)]
[llvm-cxxfilt]Add test to show that empty lines can be handled
I recently discovered a bug in llvm-cxxfilt introduced in r353743 but
was fixed later incidentally due to r355031. Specifically, llvm-cxxfilt
was attempting to call .back() on an empty string any time there was a
new line in the input. This was causing a crash in my debug builds only.
This patch simply adds a test that explicitly tests that llvm-cxxfilt
handles empty lines correctly. It may pass under release builds under
the broken behaviour, but it fails at least in debug builds.
James Henderson [Tue, 12 Mar 2019 15:37:34 +0000 (15:37 +0000)]
[FileCheck]Remove assertions that prevent matching an empty string at file start before CHECK-NEXT/SAME
This patch removes two assertions that were preventing writing of a test
that checked an empty line followed by some text. For example:
CHECK: {{^$}}
CHECK-NEXT: foo()
The assertion was because the current location the CHECK-NEXT was
scanning from was the start of the buffer. A similar issue occurred with
CHECK-SAME. These assertions don't protect against anything, as there is
already an error check that checks that CHECK-NEXT/EMPTY/SAME don't
appear first in the checks, and the following code works fine if the
pointer is at the start of the input.
Tim Northover [Tue, 12 Mar 2019 15:22:23 +0000 (15:22 +0000)]
CodeGenPrep: preserve inbounds attribute when sinking GEPs.
Targets can potentially emit more efficient code if they know address
computations never overflow. For example ILP32 code on AArch64 (which only has
64-bit address computation) can ignore the possibility of overflow with this
extra information.
Fangrui Song [Tue, 12 Mar 2019 14:20:22 +0000 (14:20 +0000)]
[SimplifyLibCalls] Simplify optimizePuts
The code might intend to replace puts("") with putchar('\n') even if the
return value is used. It failed because use_empty() was used to guard
the whole block. While returning '\n' (putchar('\n')) is technically
correct (puts is only required to return a nonnegative number on
success), doing this looks weird and there is really little benefit to
optimize puts whose return value is used. So don't do that.
Jinsong Ji [Tue, 12 Mar 2019 14:01:29 +0000 (14:01 +0000)]
[NFC][PowerPC]Assert when trying to generate directmove below P8.
This was found when we generated COPY from G8RC to F8RC in
EmitInstrWithCustomInserter without checking proper architecture,
we silently generated mtvsrd, which require P8 and up.
This is a NFC patch to add assert when we call copyPhysReg, in case
someone accidentally generate COPY between G8RC to F8RC for P7 and
below.
Simon Pilgrim [Tue, 12 Mar 2019 11:51:59 +0000 (11:51 +0000)]
Revert rL355906: [SLP] Remove redundancy of performing operand reordering twice: once in buildTree() and later in vectorizeTree().
This is a refactoring patch that removes the redundancy of performing operand reordering twice, once in buildTree() and later in vectorizeTree().
To achieve this we need to keep track of the operands within the TreeEntry struct while building the tree, and later in vectorizeTree() we are just accessing them from the TreeEntry in the right order.
This patch is the first in a series of patches that will allow for better operand reordering across chains of instructions (e.g., a chain of ADDs), as presented here: https://www.youtube.com/watch?v=gIEn34LvyNo
Simon Pilgrim [Tue, 12 Mar 2019 10:51:51 +0000 (10:51 +0000)]
[SLP] Remove redundancy of performing operand reordering twice: once in buildTree() and later in vectorizeTree().
This is a refactoring patch that removes the redundancy of performing operand reordering twice, once in buildTree() and later in vectorizeTree().
To achieve this we need to keep track of the operands within the TreeEntry struct while building the tree, and later in vectorizeTree() we are just accessing them from the TreeEntry in the right order.
This patch is the first in a series of patches that will allow for better operand reordering across chains of instructions (e.g., a chain of ADDs), as presented here: https://www.youtube.com/watch?v=gIEn34LvyNo
Sjoerd Meijer [Tue, 12 Mar 2019 09:48:02 +0000 (09:48 +0000)]
[TTI] Enable analysis of clib functions in getIntrinsicCosts. NFCI.
This is addressing the issue that we're not modeling the cost of clib functions
in TTI::getIntrinsicCosts and thus we're basically addressing this fixme:
// FIXME: This is wrong for libc intrinsics.
To enable analysis of clib functions, we not only need an intrinsic ID and
formal arguments, but also the actual user of that function so that we can e.g.
look at alignment and values of arguments. So, this is the initial plumbing to
pass the user of an intrinsinsic on to getCallCosts, which queries
getIntrinsicCosts.
Simon Tatham [Tue, 12 Mar 2019 09:28:19 +0000 (09:28 +0000)]
[TableGen] Allow 2^63-1 and 2^63-2 as int literals.
These two values correspond to the 'Empty' and 'Tombstone' special
keys defined by DenseMapInfo<int64_t>, which means that neither one
can be used as a key in DenseMap<int64_t, anything>. Hence, if you try
to use either of those values as an int literal, IntInit::get() fails
an assertion when it tries to insert them into its static cache of
int-literal objects.
Fixed by replacing the DenseMap with a std::map, which doesn't intrude
on the space of legal values of the key type.
Alex Bradbury [Tue, 12 Mar 2019 09:26:53 +0000 (09:26 +0000)]
[RISCV] Add test cases for the lp64 ABI
These are closely modeled on similar tests for the ilp32 ABI. Like those
tests, we group together tests that should be common cross lp64, lp64+lp64f,
and lp64+lp64f+lp64d ABIs.
Nathan Lanza [Mon, 11 Mar 2019 23:27:59 +0000 (23:27 +0000)]
Add Swift enumerator value for CodeView::SourceLanguage
Summary:
Swift now generates PDBs for debugging on Windows. llvm and lldb
need a language enumerator value too properly handle the output
emitted by swiftc.
David Blaikie [Mon, 11 Mar 2019 23:10:33 +0000 (23:10 +0000)]
Hexagon RDF: Replace function template (plus explicit specializations) with non-template overloads
For the design in question, overloads seem to be a much simpler and less subtle solution.
This removes ODR issues, and errors of the kind where code that uses the
specialization in question will accidentally and erroneously specialize
the primary template. This only "works" by accident; the program is
ill-formed NDR.
Craig Topper [Mon, 11 Mar 2019 22:29:00 +0000 (22:29 +0000)]
[X86] Remove ProcModel and ProcFeatures tablegen classes. Move all feature lists into a ProcessorFeatures class.
ProcFeatures was a class that just concatenated two feature lists together and gave it a name. We used it to inherit features between CPUs.
ProcModel took a two CPU feature lists and concatenated them before deferring to ProcessorModel. This was to allow inherited features and specific features to be passed to each CPU.
Both of these allowed for only very rigid CPU inheritance rules.
With this patch we now store all of the lists we were using for inheritance in one object and do any list oncatenation we want there. Then we just pass whatever list we want from this class into the ProcessorModel class for each CPU.
Hopefully this gives us more flexibility to build up feature lists in whatever ways we think make sense. Perhaps untangling ISA flags and tuning flags.
I've only touched the CPUs that were directly affected by the removal of the ProcModel and ProcFeatures classes. We should move more of the feature lists into ProcessorFeatures.
Alex Bradbury [Mon, 11 Mar 2019 21:41:22 +0000 (21:41 +0000)]
[RISCV] Do a sign-extension in a compare-and-swap of 32 bit in RV64A
AtomicCmpSwapWithSuccess is legalised into an AtomicCmpSwap plus a comparison.
This requires an extension of the value which, by default, is a
zero-extension. When we later lower AtomicCmpSwap into a PseudoCmpXchg32 and then expanded in
RISCVExpandPseudoInsts.cpp, the lr.w instruction does a sign-extension.
This mismatch of extensions causes the comparison to fail when the compared
value is negative. This change overrides TargetLowering::getExtendForAtomicOps
for RISC-V so it does a sign-extension instead.
Differential Revision: https://reviews.llvm.org/D58829
Patch by Ferran Pallarès Roca.
Alex Bradbury [Mon, 11 Mar 2019 21:35:26 +0000 (21:35 +0000)]
[RISCV] Allow fp as an alias of s0
The RISC-V Assembly Programmer's Manual defines fp as another alias of x8.
However, our tablegen rules only recognise s0. This patch adds fp as another
alias of x8. GCC also accepts fp.
Differential Revision: https://reviews.llvm.org/D59209
Patch by Ferran Pallarès Roca.
Implement basic legalizations (PromoteIntRes, PromoteIntOp,
ExpandIntRes, ScalarizeVecOp, WidenVecOp) for VECREDUCE opcodes.
There are more legalizations missing (esp float legalizations),
but there's no way to test them right now, so I'm not adding them.
This also includes a few more changes to make this work somewhat
reasonably:
* Add support for expanding VECREDUCE in SDAG. Usually
experimental.vector.reduce is expanded prior to codegen, but if the
target does have native vector reduce, it may of course still be
necessary to expand due to legalization issues. This uses a shuffle
reduction if possible, followed by a naive scalar reduction.
* Allow the result type of integer VECREDUCE to be larger than the
vector element type. For example we need to be able to reduce a v8i8
into an (nominally) i32 result type on AArch64.
* Use the vector operand type rather than the scalar result type to
determine the action, so we can control exactly which vector types are
supported. Also change the legalize vector op code to handle
operations that only have vector operands, but no vector results, as
is the case for VECREDUCE.
* Default VECREDUCE to Expand. On AArch64 (only target using VECREDUCE),
explicitly specify for which vector types the reductions are supported.
This does not handle anything related to VECREDUCE_STRICT_*.
Jonas Paulsson [Mon, 11 Mar 2019 19:00:37 +0000 (19:00 +0000)]
[RegAlloc] Avoid compile time regression with multiple copy hints.
As a fix for https://bugs.llvm.org/show_bug.cgi?id=40986 ("excessive compile
time building opencollada"), this patch makes sure that no phys reg is hinted
more than once from getRegAllocationHints().
This handles the case were many virtual registers are assigned to the same
physreg. The previous compile time fix (r343686) in weightCalcHelper() only
made sure that physical/virtual registers are passed no more than once to
addRegAllocationHint().
Brian Gesiak [Mon, 11 Mar 2019 18:31:28 +0000 (18:31 +0000)]
[coroutines][PR40979] Ignore unreachable uses across suspend points
Summary:
Depends on https://reviews.llvm.org/D59069.
https://bugs.llvm.org/show_bug.cgi?id=40979 describes a bug in which the
-coro-split pass would assert that a use was across a suspend point from
a definition. Normally this would mean that a value would "spill" across
a suspend point and thus need to be stored in the coroutine frame. However,
in this case the use was unreachable, and so it would not be necessary
to store the definition on the frame.
To prevent the assert, simply remove unreachable basic blocks from a
coroutine function before computing spills. This avoids the assert
reported in PR40979.
projects / llvm / log