Use MachineInstr& to avoid implicit conversions from
MachineBasicBlock::iterator to MachineInstr*. In one case, this could
use a range-based for loop, but the other loops iterated in reverse
order.
One of the reverse-loops checked the MachineInstr* for nullptr, a
condition that is provably unreachable. (And even if my proof has a
flaw, UBSan would catch the bug.)
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This is mostly a mechanical change to make TargetInstrInfo API take
MachineInstr& (instead of MachineInstr* or MachineBasicBlock::iterator)
when the argument is expected to be a valid MachineInstr. This is a
general API improvement.
Although it would be possible to do this one function at a time, that
would demand a quadratic amount of churn since many of these functions
call each other. Instead I've done everything as a block and just
updated what was necessary.
This is mostly mechanical fixes: adding and removing `*` and `&`
operators. The only non-mechanical change is to split
ARMBaseInstrInfo::getOperandLatencyImpl out from
ARMBaseInstrInfo::getOperandLatency. Previously, the latter took a
`MachineInstr*` which it updated to the instruction bundle leader; now,
the latter calls the former either with the same `MachineInstr&` or the
bundle leader.
As a side effect, this removes a bunch of MachineInstr* to
MachineBasicBlock::iterator implicit conversions, a necessary step
toward fixing PR26753.
Note: I updated WebAssembly, Lanai, and AVR (despite being
off-by-default) since it turned out to be easy. I couldn't run tests
for AVR since llc doesn't link with it turned on.
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We have to modify V2SU before inserting new elements into the
CurrentVRegDefs set because that may move V2SU in memory invalidating
the reference.
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Usually subregister definitions are consider uses of the remaining
lanes that did not get defined. Add a comment why the code in
ScheduleDAGInstrs does not add use dependencies regardless.
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Summary:
While setting kill flags on instructions inside a BUNDLE, we bail out as soon
as we set kill flag on a register. But we are missing a check when all the
registers already have the correct kill flag set. We need to bail out in that
case as well.
This patch refactors the old code and simply makes use of the addRegisterKilled
function in MachineInstr.cpp in order to determine whether to set/remove kill
on an instruction.
Reviewers: apazos, t.p.northover, pete, MatzeB
Subscribers: MatzeB, davide, llvm-commits
Differential Revision: http://reviews.llvm.org/D17356
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An example from Hexagon where things went wrong:
%R0<def> = L2_loadrigp <ga:@fp04> ; load function address
J2_callr %R0<kill>, ..., %R0<imp-def> ; call *R0, return value in R0
ScheduleDAGInstrs::buildSchedGraph would visit all instructions going
backwards, and in each instruction it would visit all operands in their
order on the operand list. In the case of this call, it visited the use
of R0 first, then removed it from the set Uses after it visited the def.
This caused the DAG to be missing the data dependence edge on R0 between
the load and the call.
Differential Revision: http://reviews.llvm.org/D20102
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Summary:
In getUnderlyingObjectsForInstr(): Don't give up on instructions with
multiple MMOs, instead look through all the MMOs and if they all meet
the conservative criteria previously used for single MMO instructions,
then return all of the underlying objects derived from the MMOs.
The change to ScheduleDAGInstrs::buildSchedGraph() is needed to avoid
the case where multiple underlying objects are present and are related
in such a way that successive iterations of the loop end up adding a
dependency from an instruction to itself.
Reviewers: atrick, hfinkel
Subscribers: MatzeB, mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D18093
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Patch by Jonas Paulsson. Original description:
Bugfix in buildSchedGraph() to make -dag-maps-huge-region work properly
I found that the reduction of the maps did in fact never happen in this
test case. This was because *all* the stores / loads were made with
addresses from arguments and they thus became "unknown" stores / loads.
Fixed by removing continue statements and making sure that the test for
reduction always takes place.
Differential Revision: http://reviews.llvm.org/D18673
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Update APIs in MachineInstrBundle.h to take and return MachineInstr&
instead of MachineInstr* when the instruction cannot be null. Besides
being a nice cleanup, this is tacking toward a fix for PR26753.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@262141 91177308-0d34-0410-b5e6-96231b3b80d8
Take MachineInstr by reference instead of by pointer in SlotIndexes and
the SlotIndex wrappers in LiveIntervals. The MachineInstrs here are
never null, so this cleans up the API a bit. It also incidentally
removes a few implicit conversions from MachineInstrBundleIterator to
MachineInstr* (see PR26753).
At a couple of call sites it was convenient to convert to a range-based
for loop over MachineBasicBlock::instr_begin/instr_end, so I added
MachineBasicBlock::instrs.
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Delete MachineInstr::getIterator(), since the term "iterator" is
overloaded when talking about MachineInstr.
- Downcast to ilist_node in iplist::getNextNode() and getPrevNode() so
that ilist_node::getIterator() is still available.
- Add it back as MachineInstr::getInstrIterator(). This matches the
naming in MachineBasicBlock.
- Add MachineInstr::getBundleIterator(). This is explicitly called
"bundle" (not matching MachineBasicBlock) to disintinguish it clearly
from ilist_node::getIterator().
- Update all calls. Some of these I switched to `auto` to remove
boiler-plate, since the new name is clear about the type.
There was one call I updated that looked fishy, but it wasn't clear what
the right answer was. This was in X86FrameLowering::inlineStackProbe(),
added in r252578 in lib/Target/X86/X86FrameLowering.cpp. I opted to
leave the behaviour unchanged, but I'll reply to the original commit on
the list in a moment.
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This function was basically useless, since volatile memacesses or MIs with
unmodelled sideffects become global memory objects, and the other little
checks are also done elsewhere.
Reviewed by Andy Trick
http://reviews.llvm.org/D16881
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Recommited, after some fixing with test cases.
Updated test cases:
test/CodeGen/AArch64/arm64-misched-memdep-bug.ll
test/CodeGen/AArch64/tailcall_misched_graph.ll
Temporarily disabled test cases:
test/CodeGen/AMDGPU/split-vector-memoperand-offsets.ll
test/CodeGen/PowerPC/ppc64-fastcc.ll (partially updated)
test/CodeGen/PowerPC/vsx-fma-m.ll
test/CodeGen/PowerPC/vsx-fma-sp.ll
http://reviews.llvm.org/D8705
Reviewers: Hal Finkel, Andy Trick.
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The buildSchedGraph() was in need of reworking as the AA features had been
added on top of earlier code. It was very difficult to understand, and buggy.
There had been found cases where scheduling dependencies had actually been
missed (see r228686).
AliasChain, RejectMemNodes, adjustChainDeps() and iterateChainSucc() have
been removed. There are instead now just the four maps from Value to SUs, which
have been renamed to Stores, Loads, NonAliasStores and NonAliasLoads.
An unknown store used to become the AliasChain, but now becomes a store mapped
to 'unknownValue' (in Stores). What used to be PendingLoads is instead the
list of SUs mapped to 'unknownValue' in Loads.
RejectMemNodes and adjustChainDeps() used to be a safety-net for everything.
The SU maps were sometimes cleared and SUs were put in RejectMemNodes, where
adjustChainDeps() would look. Instead of this, a more straight forward approach
is used in maintaining the SU maps without clearing them and simply letting
them grow over time. Instead of the cutt-off in adjustChainDeps() search, a
reduction of maps will be done if needed (see below).
Each SUnit either becomes the BarrierChain, or is put into one of the maps. For
each SUnit encountered, all the information about previous ones are still
available until a new BarrierChain is set, at which point the maps are cleared.
For huge regions, the algorithm becomes slow, therefore the maps will get
reduced at a threshold (current default is 1000 nodes), by a fraction (default 1/2).
These values can be tuned by use of CL options in case some test case shows that
they need to be changed (-dag-maps-huge-region and -dag-maps-reduction-size).
There has not been any considerable change observed in output quality or compile
time. There may now be more DAG edges inserted than before (i.e. if A->B->C,
then A->C is not needed). However, in a comparison run there were fewer total
calls to AA, and a somewhat improved compile time, which means this seems to
be not a problem.
http://reviews.llvm.org/D8705
Reviewers: Hal Finkel, Andy Trick.
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Note that this is disabled by default and still requires a patch to
handleMove() which is not upstreamed yet.
If the TrackLaneMasks policy/strategy is enabled the MachineScheduler
will build a schedule graph where definitions of independent
subregisters are no longer serialised.
Implementation comments:
- Without lane mask tracking a sub register def also counts as a use
(except for the first one with the read-undef flag set), with lane
mask tracking enabled this is no longer the case.
- Pressure Diffs where previously maintained per definition of a
vreg with the help of the SSA information contained in the
LiveIntervals. With lanemask tracking enabled we cannot do this
anymore and instead change the pressure diffs for all uses of the vreg
as it becomes live/dead. For this changed style to work correctly we
ignore uses of instructions that define the same register again: They
won't affect register pressure.
- With lanemask tracking we remove all read-undef flags from
sub register defs when building the graph and re-add them later when
all vreg lanes have become dead.
Differential Revision: http://reviews.llvm.org/D14969
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Previously the RegisterOperands have only been used internally in
RegisterPressure.cpp. However this datastructure can be useful for other
tasks as well and allows refactoring of PDiff initialisation out of
RPTracker::recede().
This patch:
- Exposes RegisterOperands as public API
- Splits RPTracker::recede() into a part that skips DebugValues and
maintains the region borders, and the core that changes register
pressure when given a set of RegisterOperands.
- This allows to move the PDiff initialisation out recede() into a
method of the PressureDiffs class.
- The upcoming subregister scheduling code will also use
RegisterOperands to avoid pushing more unrelated functionality into
recede()/advance().
Differential Revision: http://reviews.llvm.org/D15473
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Summary:
In buildSchedGraph(), when adding memory dependencies for loads, move
the call to adjustChainDeps() after the call to
addChainDependency(AliasChain) to handle the case where
addChainDependency(AliasChain) ends up not adding a dependency and
instead putting the SU on the RejectMemNodes list. The call to
adjustChainDeps() must be done after the call to addChainDependency() in
order to process the SU added to the RejectMemNodes list to create
memory dependencies for it.
Reviewers: hfinkel, atrick, jonpa, resistor
Subscribers: mcrosier, llvm-commits
Differential Revision: http://reviews.llvm.org/D15927
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Now that ScheduleDAGInstrs doesn't need it anymore we can move the field
down the class hierarcy to ScheduleDAGMI.
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Re-comitting with a change that avoids undefined uses getting put into
the VRegUses list.
The new algorithm remembers the uses encountered while walking backwards
until a matching def is found. Contrary to the previous version this:
- Works without LiveIntervals being available
- Allows to increase the precision to subregisters/lanemasks
(not used for now)
The changes in the AMDGPU tests are necessary because the R600 scheduler
is not stable with respect to the order of nodes in the ready queues.
Differential Revision: http://reviews.llvm.org/D9068
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This works mostly fine but breaks some stage 1 builders when compiling
compiler-rt on i386. Revert for further investigation as I can't see an
obvious cause/fix.
This reverts commit r254577.
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The new algorithm remembers the uses encountered while walking backwards
until a matching def is found. Contrary to the previous version this:
- Works without LiveIntervals being available
- Allows to increase the precision to subregisters/lanemasks
(not used for now)
The changes in the AMDGPU tests are necessary because the R600 scheduler
is not stable with respect to the order of nodes in the ready queues.
Differential Revision: http://reviews.llvm.org/D9068
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ScheduleDAGInstrs doesn't behave differently before or after register
allocation. It was only used in a method of MachineSchedulerBase which
behaved differently in MachineScheduler/PostMachineScheduler. Change
this to let MachineScheduler/PostMachineScheduler just pass in a
parameter to that function.
The order of the LiveIntervals* and bool RemoveKillFlags paramters have
been switched to make out-of-tree code fail instead of unintentionally
passing a value intended for the IsPostRA flag to the (previously
following and default initialized) RemoveKillFlags.
Differential Revision: http://reviews.llvm.org/D14245
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This was a layering violation in ScheduleDAGInstrs (and
MachineSchedulerBase) they both shouldn't know directly whether they are
used by the PostMachineScheduler or the MachineScheduler.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251608 91177308-0d34-0410-b5e6-96231b3b80d8
With subregister liveness enabled we can detect the case where only
parts of a register are live in, this is expressed as a 32bit lanemask.
The current code only keeps registers in the live-in list and therefore
enumerated all subregisters affected by the lanemask. This turned out to
be too conservative as the subregister may also cover additional parts
of the lanemask which are not live. Expressing a given lanemask by
enumerating a minimum set of subregisters is computationally expensive
so the best solution is to simply change the live-in list to store the
lanemasks as well. This will reduce memory usage for targets using
subregister liveness and slightly increase it for other targets
Differential Revision: http://reviews.llvm.org/D12442
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@247171 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This change is part of a series of commits dedicated to have a single
DataLayout during compilation by using always the one owned by the
module.
This patch is quite boring overall, except for some uglyness in
ASMPrinter which has a getDataLayout function but has some clients
that use it without a Module (llmv-dsymutil, llvm-dwarfdump), so
some methods are taking a DataLayout as parameter.
Reviewers: echristo
Subscribers: yaron.keren, rafael, llvm-commits, jholewinski
Differential Revision: http://reviews.llvm.org/D11090
From: Mehdi Amini <mehdi.amini@apple.com>
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This will allow classes to implement the AA interface without deriving
from the class or referencing an internal enum of some other class as
their return types.
Also, to a pretty fundamental extent, concepts such as 'NoAlias',
'MayAlias', and 'MustAlias' are first class concepts in LLVM and we
aren't saving anything by scoping them heavily.
My mild preference would have been to use a scoped enum, but that
feature is essentially completely broken AFAICT. I'm extremely
disappointed. For example, we cannot through any reasonable[1] means
construct an enum class (or analog) which has scoped names but converts
to a boolean in order to test for the possibility of aliasing.
[1]: Richard Smith came up with a "solution", but it requires class
templates, and lots of boilerplate setting up the enumeration multiple
times. Something like Boost.PP could potentially bundle this up, but
even that would be quite painful and it doesn't seem realistically worth
it. The enum class solution would probably work without the need for
a bool conversion.
Differential Revision: http://reviews.llvm.org/D10495
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The patch is generated using this command:
tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
llvm/lib/
Thanks to Eugene Kosov for the original patch!
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that it is its own entity in the form of MemoryLocation, and update all
the callers.
This is an entirely mechanical change. References to "Location" within
AA subclases become "MemoryLocation", and elsewhere
"AliasAnalysis::Location" becomes "MemoryLocation". Hope that helps
out-of-tree folks update.
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MIOperands/ConstMIOperands are classes iterating over the MachineOperand
of a MachineInstr, however MachineInstr::mop_iterator does the same
thing.
I assume these two iterators exist to have a uniform interface to
iterate over the operands of a machine instruction bundle and a single
machine instruction. However in practice I find it more confusing to have 2
different iterator classes, so this patch transforms (nearly all) the
code to use mop_iterators.
The only exception being MIOperands::anlayzePhysReg() and
MIOperands::analyzeVirtReg() still needing an equivalent, I leave that
as an exercise for the next patch.
Differential Revision: http://reviews.llvm.org/D9932
This version is slightly modified from the proposed revision in that it
introduces MachineInstr::getOperandNo to avoid the extra counting
variable in the few loops that previously used MIOperands::getOperandNo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238539 91177308-0d34-0410-b5e6-96231b3b80d8
DEBUG_VALUE nodes do not take part in code generation. Ignore them when
performing KILL updates. Addresses PR23486.
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