Helper functions to identify sign- and zero-extending machine instruction is introduced in rL315888.
This patch makes PPCInstrInfo::optimizeCompareInstr use the helper functions. It simplifies the code and also makes possible more optimizations since the helper can do more analysis than the original check code; I observed about 5000 more compare instructions are eliminated while building LLVM.
Also, this patch fixes a bug in helpers on ANDIo instruction handling due to the order of checks. This bug causes a failure in an existing test case for optimizeCompareInstr.
Differential Revision: https://reviews.llvm.org/D38988
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316071 91177308-0d34-0410-b5e6-96231b3b80d8
This patch enables redundant sign- and zero-extension elimination in PowerPC MI Peephole pass.
If the input value of a sign- or zero-extension is known to be already sign- or zero-extended, the operation is redundant and can be eliminated.
One common case is sign-extensions for a method parameter or for a method return value; they must be sign- or zero-extended as defined in PPC ELF ABI.
For example of the following simple code, two extsw instructions are generated before the invocation of int_func and before the return. With this patch, both extsw are eliminated.
void int_func(int);
void ii_test(int a) {
if (a & 1) return int_func(a);
}
Such redundant sign- or zero-extensions are quite common in many programs; e.g. I observed about 60,000 occurrences of the elimination while compiling the LLVM+CLANG.
Differential Revision: https://reviews.llvm.org/D31319
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315888 91177308-0d34-0410-b5e6-96231b3b80d8
Add profitability checks for modifying counted loops to use the mtctr instruction.
The latency of mtctr is only justified if there are more than 4 comparisons that
will be removed as a result. Usually counted loops are formed relatively early
and before unrolling, so most low trip count loops often don't survive. However
we want to ensure that if they do, we do not mistakenly update them to mtctr loops.
Use CodeMetrics to ensure we are only doing this for small loops with small trip counts.
Differential Revision: https://reviews.llvm.org/D38212
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315592 91177308-0d34-0410-b5e6-96231b3b80d8
Currently we produce a bunch of unnecessary code when emitting the
prologue/epilogue for spills/restores. Namely, if the load from stack
slot/store to stack slot instruction is an X-Form instruction, we will
always produce an LIS/ORI sequence for the stack offset.
Furthermore, we have not exploited the P9 vector D-Form loads/stores for this
purpose.
This patch address both issues.
Specifying the D-Form load as the instruction to use for stack spills/reloads
should be safe because:
1. The stack should be aligned according to the ABI
2. If the stack isn't aligned, PPCRegisterInfo::eliminateFrameIndex() will
check for the offset being a multiple of 16 and will convert it to an
X-Form instruction if it isn't.
Differential Revision : https://reviews.llvm.org/D38758
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315500 91177308-0d34-0410-b5e6-96231b3b80d8
The issue is that we assume operand zero of the input to the add instruction
is a register. In this case, the input comes from inline assembly and
operand zero is not a register thereby causing a crash.
The code will bail anyway if the input instruction doesn't have the right
opcode. So do that check first and let short-circuiting prevent the crash.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315285 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This suppresses the generation of .Lcfi labels in our textual assembler.
It was annoying that this generated cascading .Lcfi labels:
llc foo.ll -o - | llvm-mc | llvm-mc
After three trips through MCAsmStreamer, we'd have three labels in the
output when none are necessary. We should only bother creating the
labels and frame data when making a real object file.
This supercedes D38605, which moved the entire .seh_ implementation into
MCObjectStreamer.
This has the advantage that we do more checking when emitting textual
assembly, as a minor efficiency cost. Outputting textual assembly is not
performance critical, so this shouldn't matter.
Reviewers: majnemer, MatzeB
Subscribers: qcolombet, nemanjai, javed.absar, eraman, hiraditya, JDevlieghere, llvm-commits
Differential Revision: https://reviews.llvm.org/D38638
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315259 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r314729.
Another bug has been encountered in an out-of-tree target reported by Quentin.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314814 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Take the target's endianness into account when splitting the
debug information in DAGTypeLegalizer::SetExpandedInteger.
This patch fixes so that, for big-endian targets, the fragment
expression corresponding to the high part of a split integer
value is placed at offset 0, in order to correctly represent
the memory address order.
I have attached a PPC32 reproducer where the resulting DWARF
pieces for a 64-bit integer were incorrectly reversed.
Original patch was reverted due to using -stop-after=isel in
the test case (but that is only working when AMDGPU target
is included in the llc build). The test case has now been
updated to use -stop-before=expand-isel-pseudos instead.
Patch by: dstenb
Reviewers: JDevlieghere, aprantl, dblaikie
Reviewed By: JDevlieghere, aprantl, dblaikie
Subscribers: nemanjai
Differential Revision: https://reviews.llvm.org/D38172
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314781 91177308-0d34-0410-b5e6-96231b3b80d8
Issues addressed since original review:
- Avoid bug in regalloc greedy/machine verifier when forwarding to use
in an instruction that re-defines the same virtual register.
- Fixed bug when forwarding to use in EarlyClobber instruction slot.
- Fixed incorrect forwarding to register definitions that showed up in
explicit_uses() iterator (e.g. in INLINEASM).
- Moved removal of dead instructions found by
LiveIntervals::shrinkToUses() outside of loop iterating over
instructions to avoid instructions being deleted while pointed to by
iterator.
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
doing so can break code that implicitly relies on the physical
register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
can break the machine verifier by creating LiveRanges that don't
end on a use (since the undef operand is not considered a use).
[MachineCopyPropagation] Extend pass to do COPY source forwarding
This change extends MachineCopyPropagation to do COPY source forwarding.
This change also extends the MachineCopyPropagation pass to be able to
be run during register allocation, after physical registers have been
assigned, but before the virtual registers have been re-written, which
allows it to remove virtual register COPY LiveIntervals that become dead
through the forwarding of all of their uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314729 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Take the target's endianness into account when splitting the
debug information in DAGTypeLegalizer::SetExpandedInteger.
This patch fixes so that, for big-endian targets, the fragment
expression corresponding to the high part of a split integer
value is placed at offset 0, in order to correctly represent
the memory address order.
I have attached a PPC32 reproducer where the resulting DWARF
pieces for a 64-bit integer were incorrectly reversed.
Patch by: dstenb
Reviewers: JDevlieghere, aprantl, dblaikie
Reviewed By: JDevlieghere, aprantl, dblaikie
Subscribers: nemanjai
Differential Revision: https://reviews.llvm.org/D38172
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314666 91177308-0d34-0410-b5e6-96231b3b80d8
This patch add a support of ISD::ZERO_EXTEND in PPCDAGToDAGISel::tryBitPermutation to increase the opportunity to use rotate-and-mask by reordering ZEXT and ANDI.
Since tryBitPermutation stops analyzing nodes if it hits a ZEXT node while traversing SDNodes, we want to avoid ZEXT between two nodes that can be folded into a rotate-and-mask instruction.
For example, we allow these nodes
t9: i32 = add t7, Constant:i32<1>
t11: i32 = and t9, Constant:i32<255>
t12: i64 = zero_extend t11
t14: i64 = shl t12, Constant:i64<2>
to be folded into a rotate-and-mask instruction.
Such case often happens in array accesses with logical AND operation in the index, e.g. array[i & 0xFF];
Differential Revision: https://reviews.llvm.org/D37514
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314655 91177308-0d34-0410-b5e6-96231b3b80d8
This is a follow-on of D37211.
D37211 eliminates a compare instruction if two conditional branches can be made based on the one compare instruction, e.g.
if (a == 0) { ... }
else if (a < 0) { ... }
This patch extends this optimization to support partially redundant cases, which often happen in while loops.
For example, one compare instruction is moved from the loop body into the preheader by this optimization in the following example.
do {
if (a == 0) dummy1();
a = func(a);
} while (a > 0);
Differential Revision: https://reviews.llvm.org/D38236
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314390 91177308-0d34-0410-b5e6-96231b3b80d8
This patch makes analyzeBranch eliminate unconditional branch to the next instruction.
After basic blocks are re-organized by optimizers, such as machine block placement, a BB may end with an unconditional branch to the next (fallthrough) BB. This patch removes such redundant branch instruction.
Differential Revision: https://reviews.llvm.org/D37730
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314297 91177308-0d34-0410-b5e6-96231b3b80d8
In the past while, I've committed a number of patches in the PowerPC back end
aimed at eliminating comparison instructions. However, this causes some failures
in proprietary source and these issues are not observed in SPEC or any open
source packages I've been able to run.
As a result, I'm pulling the entire series and will refactor it to:
- Have a single entry point for easy control
- Have fine-grained control over which patterns we transform
A side-effect of this is that test cases for these patches (and modified by
them) are XFAIL-ed. This is a temporary measure as it is counter-productive
to remove/modify these test cases and then have to modify them again when
the refactored patch is recommitted.
The failure will be investigated in parallel to the refactoring effort and
the recommit will either have a fix for it or will leave this transformation
off by default until the problem is resolved.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314244 91177308-0d34-0410-b5e6-96231b3b80d8
Summary: Conditional returns were not taken into consideration at all. Implement them by turning them into jumps and normal returns. This means there is a slightly higher performance penalty for conditional returns, but this is the best we can do, and it still disturbs little of the rest.
Reviewers: dberris, echristo
Subscribers: sanjoy, nemanjai, hiraditya, kbarton, llvm-commits
Differential Revision: https://reviews.llvm.org/D38102
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314005 91177308-0d34-0410-b5e6-96231b3b80d8
This patch re-commits the patch that was pulled out due to a
problem it caused, but with a fix for the problem. The fix
was reviewed separately by Eric Christopher and Hal Finkel.
Differential Revision: https://reviews.llvm.org/D38054
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313978 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
SelectionDAGISel::LowerArguments is associating arguments
with frame indices (FuncInfo->setArgumentFrameIndex). That
information is later on used by EmitFuncArgumentDbgValue to
create DBG_VALUE instructions that denotes that a variable
can be found on the stack.
I discovered that for our (big endian) out-of-tree target
the association created by SelectionDAGISel::LowerArguments
sometimes is wrong. I've seen this happen when a 64-bit value
is passed on the stack. The argument will occupy two stack
slots (frame index X, and frame index X+1). The fault is
that a call to setArgumentFrameIndex is associating the
64-bit argument with frame index X+1. The effect is that the
debug information (DBG_VALUE) will point at the least significant
part of the arguement on the stack. When printing the
argument in a debugger I will get the wrong value.
I managed to create a test case for PowerPC that seems to
show the same kind of problem.
The bugfix will look at the datalayout, taking endianness into
account when examining a BUILD_PAIR node, assuming that the
least significant part is in the first operand of the BUILD_PAIR.
For big endian targets we should use the frame index from
the second operand, as the most significant part will be stored
at the lower address (using the highest frame index).
Reviewers: bogner, rnk, hfinkel, sdardis, aprantl
Reviewed By: aprantl
Subscribers: nemanjai, aprantl, llvm-commits, igorb
Differential Revision: https://reviews.llvm.org/D37740
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313901 91177308-0d34-0410-b5e6-96231b3b80d8
This patch updates register allocation to enable spilling gprs to
volatile vector registers rather than the stack. It can be enabled
for Power9 with option -ppc-enable-gpr-to-vsr-spills.
Differential Revision: https://reviews.llvm.org/D34815
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313886 91177308-0d34-0410-b5e6-96231b3b80d8
Two blocks prior to the join each perform an li and the the join block has an
add using the initialized register. Optimize each predecessor block to instead
use addi and delete the li's and add.
Differential Revision: https://reviews.llvm.org/D36734
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313639 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
XRay had been assuming that the previous section is the "text" section
of the function when lowering the instrumentation map. Unfortunately
this is not a safe assumption, because we may be coming from lowering
debug type information for the function being lowered.
This fixes an issue with combining -gsplit-dwarf, -generate-type-units,
-debug-compile and -fxray-instrument for sole member functions. When the
split dwarf section is stripped, we're left with references from the
xray_instr_map to the debug section. The change now uses the function's
symbol instead of the previous section's start symbol.
We found the bug while attempting to strip the split debug sections off
an XRay-instrumented object file, which had a peculiar edge-case for
single-function classes where the single function is being lowered.
Because XRay had assocaited the instrumentation map for a function to
the debug types section instead of the function's section, the objcopy
call will fail due to the misplaced reference from the xray_instr_map
section.
Reviewers: pcc, dblaikie, echristo
Subscribers: llvm-commits, aprantl
Differential Revision: https://reviews.llvm.org/D37791
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313233 91177308-0d34-0410-b5e6-96231b3b80d8
Implementing this pass as a PowerPC specific pass. Branch coalescing utilizes
the analyzeBranch method which currently does not include any implicit operands.
This is not an issue on PPC but must be handled on other targets.
Pass is currently off by default. Enabled via -enable-ppc-branch-coalesce.
Differential Revision : https: // reviews.llvm.org/D32776
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@313061 91177308-0d34-0410-b5e6-96231b3b80d8
The lxv/stxv instructions require an offset that is 0 % 16. Previously we were
selecting lxv/stxv for loads and stores to the stack where the offset from the
slot was a multiple of 16, but the stack slot was not 16 or more byte aligned.
When the frame gets lowered these transform to r(1|31) + slot + offset.
If slot is not aligned, slot + offset may not be 0 % 16.
Now we require 16 byte or more alignment for select lxv/stxv to stack slots.
Includes a testcase that shows both sufficiently and insufficiently aligned
stack slots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312843 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This fixes code-gen for XRay in PPC. The regression wasn't caught by
codegen tests which we add in this change.
What happened was the following:
- For tail exits, we used to unconditionally prepend the returns/exits
with a pseudo-instruction that gets lowered to the instrumentation
sled (and leave the actual return/exit instruction as-is).
- Changes to the XRay instrumentation pass caused the tail exits to
suddenly also emit the tail exit pseudo-instruction, since the check
for whether a return instruction was also a call instruction meant it
was a tail exit instruction.
- None of the tests caught the regression either due to non-existent
tests, or the tests being disabled/removed for continuous breakage.
This change re-introduces some of the basic tests and verifies that
we're back to a state that allows the back-end to generate appropriate
XRay instrumented binaries for PPC in the presence of tail exits.
Reviewers: echristo, timshen
Subscribers: nemanjai, kbarton, llvm-commits
Differential Revision: https://reviews.llvm.org/D37570
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312772 91177308-0d34-0410-b5e6-96231b3b80d8
xscvdpspn was not introduced until the P8, so don't use it on the P7. Fixes a
regression introduced in r288152.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312612 91177308-0d34-0410-b5e6-96231b3b80d8
If multiple conditional branches are executed based on the same comparison, we can execute multiple conditional branches based on the result of one comparison on PPC. For example,
if (a == 0) { ... }
else if (a < 0) { ... }
can be executed by one compare and two conditional branches instead of two pairs of a compare and a conditional branch.
This patch identifies a code sequence of the two pairs of a compare and a conditional branch and merge the compares if possible.
To maximize the opportunity, we do canonicalization of code sequence before merging compares.
For the above example, the input for this pass looks like:
cmplwi r3, 0
beq 0, .LBB0_3
cmpwi r3, -1
bgt 0, .LBB0_4
So, before merging two compares, we canonicalize it as
cmpwi r3, 0 ; cmplwi and cmpwi yield same result for beq
beq 0, .LBB0_3
cmpwi r3, 0 ; greather than -1 means greater or equal to 0
bge 0, .LBB0_4
The generated code should be
cmpwi r3, 0
beq 0, .LBB0_3
bge 0, .LBB0_4
Differential Revision: https://reviews.llvm.org/D37211
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312514 91177308-0d34-0410-b5e6-96231b3b80d8
Issues addressed since original review:
- Moved removal of dead instructions found by
LiveIntervals::shrinkToUses() outside of loop iterating over
instructions to avoid instructions being deleted while pointed to by
iterator.
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
doing so can break code that implicitly relies on the physical
register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
can break the machine verifier by creating LiveRanges that don't
end on a use (since the undef operand is not considered a use).
[MachineCopyPropagation] Extend pass to do COPY source forwarding
This change extends MachineCopyPropagation to do COPY source forwarding.
This change also extends the MachineCopyPropagation pass to be able to
be run during register allocation, after physical registers have been
assigned, but before the virtual registers have been re-written, which
allows it to remove virtual register COPY LiveIntervals that become dead
through the forwarding of all of their uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312328 91177308-0d34-0410-b5e6-96231b3b80d8
From comments and code review it wasn't intended to be enabled by default yet.
This reverts commit r311588.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312214 91177308-0d34-0410-b5e6-96231b3b80d8
It caused PR34387: Assertion failed: (RegNo < NumRegs && "Attempting to access record for invalid register number!")
> Issues identified by buildbots addressed since original review:
> - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
> - The pass no longer forwards COPYs to physical register uses, since
> doing so can break code that implicitly relies on the physical
> register number of the use.
> - The pass no longer forwards COPYs to undef uses, since doing so
> can break the machine verifier by creating LiveRanges that don't
> end on a use (since the undef operand is not considered a use).
>
> [MachineCopyPropagation] Extend pass to do COPY source forwarding
>
> This change extends MachineCopyPropagation to do COPY source forwarding.
>
> This change also extends the MachineCopyPropagation pass to be able to
> be run during register allocation, after physical registers have been
> assigned, but before the virtual registers have been re-written, which
> allows it to remove virtual register COPY LiveIntervals that become dead
> through the forwarding of all of their uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312178 91177308-0d34-0410-b5e6-96231b3b80d8
Issues identified by buildbots addressed since original review:
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
doing so can break code that implicitly relies on the physical
register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
can break the machine verifier by creating LiveRanges that don't
end on a use (since the undef operand is not considered a use).
[MachineCopyPropagation] Extend pass to do COPY source forwarding
This change extends MachineCopyPropagation to do COPY source forwarding.
This change also extends the MachineCopyPropagation pass to be able to
be run during register allocation, after physical registers have been
assigned, but before the virtual registers have been re-written, which
allows it to remove virtual register COPY LiveIntervals that become dead
through the forwarding of all of their uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312154 91177308-0d34-0410-b5e6-96231b3b80d8
This change simplifies code that has to deal with
DIGlobalVariableExpression and mirrors how we treat DIExpressions in
debug info intrinsics. Before this change there were two ways of
representing empty expressions on globals, a nullptr and an empty
!DIExpression().
If someone needs to upgrade out-of-tree testcases:
perl -pi -e 's/(!DIGlobalVariableExpression\(var: ![0-9]*)\)/\1, expr: !DIExpression())/g' <MYTEST.ll>
will catch 95%.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@312144 91177308-0d34-0410-b5e6-96231b3b80d8
This goes back to a discussion about IR canonicalization. We'd like to preserve and convert
more IR to 'select' than we currently do because that's likely the best choice in IR:
http://lists.llvm.org/pipermail/llvm-dev/2016-September/105335.html
...but that's often not true for codegen, so we need to account for this pattern coming in
to the backend and transform it to better DAG ops.
Steps in this patch:
1. Add an EVT param to the existing convertSelectOfConstantsToMath() TLI hook to more finely
enable this transform. Other targets will probably want that anyway to distinguish scalars
from vectors. We're using that here to exclude AVX512 targets, but it may not be necessary.
2. Convert a vselect to ext+add. This eliminates a constant load/materialization, and the
vector ext is often free.
Implementing a more general fold using xor+and can be a follow-up for targets that don't have
a legal vselect. It's also possible that we can remove the TLI hook for the special case fold
implemented here because we're eliminating a constant, but it needs to be tested on other
targets.
Differential Revision: https://reviews.llvm.org/D36840
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311731 91177308-0d34-0410-b5e6-96231b3b80d8
Implementing this pass as a PowerPC specific pass. Branch coalescing utilizes
the analyzeBranch method which currently does not include any implicit operands.
This is not an issue on PPC but must be handled on other targets.
Differential Revision : https: // reviews.llvm.org/D32776
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311588 91177308-0d34-0410-b5e6-96231b3b80d8
- recommitting after fixing a test failure on MacOS
On PPC64, OR (XOR) with a 32-bit immediate can be done with only two instructions, i.e. ori + oris.
But the current LLVM generates three or four instructions for this purpose (and also it clobbers one GPR).
This patch makes PPC backend generate ori + oris (xori + xoris) for OR (XOR) with a 32-bit immediate.
e.g. (x | 0xFFFFFFFF) should be
ori 3, 3, 65535
oris 3, 3, 65535
but LLVM generates without this patch
li 4, 0
oris 4, 4, 65535
ori 4, 4, 65535
or 3, 3, 4
Differential Revision: https://reviews.llvm.org/D34757
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311538 91177308-0d34-0410-b5e6-96231b3b80d8
On PPC64, OR (XOR) with a 32-bit immediate can be done with only two instructions, i.e. ori + oris.
But the current LLVM generates three or four instructions for this purpose (and also it clobbers one GPR).
This patch makes PPC backend generate ori + oris (xori + xoris) for OR (XOR) with a 32-bit immediate.
e.g. (x | 0xFFFFFFFF) should be
ori 3, 3, 65535
oris 3, 3, 65535
but LLVM generates without this patch
li 4, 0
oris 4, 4, 65535
ori 4, 4, 65535
or 3, 3, 4
Differential Revision: https://reviews.llvm.org/D34757
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311526 91177308-0d34-0410-b5e6-96231b3b80d8
