The previous names were both misleading (the MachineLegalizer actually
contained the info tables) and inconsistent with the selector & translator (in
having a "Machine") prefix. This should make everything sensible again.
The only functional change is the name of a couple of command-line options.
llvm-svn: 284287
The core of the change is supposed to be NFC, however it also fixes
what I believe was an undefined behavior when calling:
va_start(ValueArgs, Desc);
with Desc being a StringRef.
Differential Revision: https://reviews.llvm.org/D25342
llvm-svn: 283671
Instead of producing a mapping for all the operands, we only generate a
mapping for the definition. Indeed, the other operands are not
constrained by the instruction and thus, we should leave the choice to
the actual definition to do the right thing.
In pratice this is almost NFC, but with one advantage. We will have only
one instance of OperandsMapping for each copy and phi that map to one
register bank instead of one different instance for each different
number of operands for each copy and phi.
llvm-svn: 282756
This is a step toward statically allocate InstructionMapping. Like the
previous few commits, the goal is to move toward a TableGen'ed like
structure with no dynamic allocation at all.
This should already improve compile time by getting rid of a bunch of
memmove of SmallVectors.
llvm-svn: 282643
This is a step toward statically allocate ValueMapping. Like the
previous few commits, the goal is to move toward a TableGen'ed like
structure with no dynamic allocation at all.
llvm-svn: 282324
Previously we were using the address of the unique instance of a partial
mapping in the related map to access this instance. However, when the
map grows, the whole set of instances may be moved elsewhere and the
previous addresses are not valid anymore.
Instead, keep the address of the unique heap allocated instance of a
partial mapping.
Note: I did not see any actual bugs for that problem as the number of
partial mappings dynamically allocated is small (<= 4).
llvm-svn: 282323
Collect statistics about the number of partial mappings dynamically
allocated and accessed. Ultimately, when the whole TableGen
infrastructure is set, those numbers should be zero.
llvm-svn: 282274
In the verify method of the ValueMapping class we used to check that the
mapping exactly matches the bits of the input value. This is problematic
for statically allocated mappings because we would need a different
mapping for each different size of the value that maps on one
instruction. For instance, with such scheme, we would need a different
mapping for a value of size 1, 5, 23 whereas they all end up on a 32-bit
wide instruction.
Therefore, change the verifier to check that the meaningful bits are
covered by the mapping instead of matching them.
llvm-svn: 282214
This is another step toward TableGen'ed like structures. The BreakDown of
the mapping of the value will be statically computed by TableGen, thus
we only have to point to the right entry in the table instead of
dynamically allocate the mapping for each instruction.
We still support the dynamic allocation through a factory of
PartialMapping to ease the bring-up of the targets while the TableGen
backend is not available.
llvm-svn: 282213
This commit is basically the first step toward what will
RegisterBankInfo look when it gets TableGen'ed.
It introduces a XXXGenRegisterBankInfo.def file that is what TableGen
will issue at some point. Moreover, the RegBanks field in
RegisterBankInfo changed to reflect the static (compile time) aspect of
the information.
llvm-svn: 282131
When initializing an instance of OperandsMapper, instead of using
SmallVector::resize followed by std::fill, use the function that
directly does that in SmallVector.
llvm-svn: 282130
We still don't really have an equivalent of "AssertXExt" in DAG, so we don't
exploit the guarantees on the receiving side yet, but this should produce
conservatively correct code on iOS ABIs.
llvm-svn: 282069
The only implementation that exists immediately looks it up anyway, and the
information is needed to handle various parameter attributes (stored on the
function itself).
llvm-svn: 282068
This should match the existing behaviour for passing complicated struct and
array types, in particular HFAs come through like that from Clang.
For C & C++ we still need to somehow support all the weird ABI flags, or at
least those that are present in the IR (signext, byval, ...), and stack-based
parameter passing.
llvm-svn: 281977
The OperandsMapper class is used heavy in RegBankSelect and each
instantiation triggered a heap allocation for the array of operands.
Instead, use a SmallVector with a big enough size such that most of the
cases do not have to use dynamically allocated memory.
This improves the compile time of the RegBankSelect pass.
llvm-svn: 281916
It was only really there as a sentinel when instructions had to have precisely
one type. Now that registers are typed, each register really has to have a type
that is sized.
llvm-svn: 281599
Otherwise everything that needs to work out what size they are has to keep a
DataLayout handy, which is a bit silly and very annoying.
llvm-svn: 281597
Unlike SDag, we use a separate G_GEP instruction (much simplified, only taking
a single byte offset) to preserve the pointer type information through
selection.
llvm-svn: 281205
These instructions were only necessary when type information was stored in the
MachineInstr (because only generic MachineInstrs possessed a type). Now that
it's in MachineRegisterInfo, COPY and PHI work fine.
llvm-svn: 281037
We want each register to have a canonical type, which means the best place to
store this is in MachineRegisterInfo rather than on every MachineInstr that
happens to use or define that register.
Most changes following from this are pretty simple (you need an MRI anyway if
you're going to be doing any transformations, so just check the type there).
But legalization doesn't really want to check redundant operands (when, for
example, a G_ADD only ever has one type) so I've made use of MCInstrDesc's
operand type field to encode these constraints and limit legalization's work.
As an added bonus, more validation is possible, both in MachineVerifier and
MachineIRBuilder (coming soon).
llvm-svn: 281035
They're another source of generic vregs, which are going to need a type on the
definition when we remove the register width from MachineRegisterInfo.
llvm-svn: 280412
More preparation for dropping source types from MachineInstrs: regsters coming
out of already-selected code (i.e. non-generic instructions) don't have a type,
but that information is needed so we must add it manually.
This is done via a new G_TYPE instruction.
llvm-svn: 280292
Legalization ends up creating many G_SEQUENCE/G_EXTRACT pairs which leads to
inefficient codegen (even for -O0), so add a quick pass over the function to
remove them again.
llvm-svn: 280155
Instead of putting all possible requests into a single table, we can perform
the extremely dense lookup based on opcode and type-index in constant time
using multi-dimensional array-like things.
This roughly halves the time spent doing legalization, which was dominated by
queries against the Actions table.
llvm-svn: 280011
There should be no functional change here, I'm just making the implementation
of "frem" (to libcall) legalization easier for a followup.
llvm-svn: 279987
It's unclear how the old
%res(32) = G_ICMP { s32, s32 } intpred(eq), %0, %1
is actually different from an s1 verison
%res(1) = G_ICMP { s1, s32 } intpred(eq), %0, %1
so we'll remove it for now.
llvm-svn: 279843
since 2015 (n4387), though it's allowed by a library DR so new implementations
accept it in their C++11 modes...
This should unbreak the build with libstdc++ 4.9.
llvm-svn: 279583
They really should have both types represented, but early variants were created
before MachineInstrs could have multiple types so they're rather ambiguous.
llvm-svn: 279567
Instructions like G_ICMP have multiple types that may need to be legalized (the
boolean output and nearly arbitrary inputs in this case). So the legalizer must
be capable of deciding what to do for each of them separately.
llvm-svn: 279554
This adds a G_INSERT instruction, which technically makes G_SEQUENCE redundant
(it's equivalent to a G_INSERT into an IMPLICIT_DEF). We'll leave G_SEQUENCE
for now though: it's likely to be far more common as it's a fundamental part of
legalization, so avoiding the mess and bloat of the extra IMPLICIT_DEFs is
probably worthwhile.
llvm-svn: 279306
First, make sure all types involved are represented, rather than being implicit
from the register width.
Second, canonicalize all types to scalar. These operations just act in bits and
don't care about vectors.
Also standardize spelling of Indices in the MachineIRBuilder (NFC here).
llvm-svn: 279294
Unsigned addition and subtraction can reuse the instructions created to
legalize large width operations (i.e. both produce and consume a carry flag).
Signed operations and multiplies get a dedicated op-with-overflow instruction.
Once this is produced the two values are combined into a struct register (which
will almost always be merged with a corresponding G_EXTRACT as part of
legalization).
llvm-svn: 279278
It's sharing the integer G_CONSTANT for now since I don't *think* it creates
any ambiguity (even on weird archs). If that turns out wrong we can create a
G_PTRCONSTANT or something.
llvm-svn: 278423
It's more than just inttoptr, but the others can't be tested until we have
support for non-trivial constants (they currently get unavoidably folded to a
ConstantInt).
llvm-svn: 278303
If the value produced by the bitcast hasn't been referenced yet, we can simply
reuse the input register avoiding an unnecessary COPY instruction.
llvm-svn: 278245
For now put them all in the entry block. This should be correct but may give
poor runtime performance. Hopefully MachineSinking combined with
isReMaterializable can solve those issues, but if not the interface is sound
enough to support alternatives.
llvm-svn: 278168
These are the operations that are trivially identical. Division is omitted for
now because you need to use the correct sign/zero extension.
llvm-svn: 277775
None of GlobalISel requires the property, but this lets us use the
verifier instead of rolling our own "all instructions selected" check.
llvm-svn: 277484
RegBankSelect and InstructionSelect run after the legalizer and
require a Legalized function: check that all instructions are legal.
Note that this should be in the MachineVerifier, but it can't use the
MachineLegalizer as it's currently in the separate GlobalISel library.
Note that the RegBankSelect verifier checks have the same layering
problem, but we only use inline methods so end up not needing to link
against the GlobalISel library.
llvm-svn: 277472
These come in two variants for now: G_INTRINSIC and G_INTRINSIC_W_SIDE_EFFECTS.
We may decide to split the latter up with finer-grained restrictions later, if
necessary.
llvm-svn: 277224
For MachineInstrBuilder, having to manually use RegState::Define is ugly and
makes register definitions clunkier than they need to be, so this adds two
convenience functions: addDef and addUse.
For MachineIRBuilder, we want to avoid BuildMI's first-reg-is-def rule because
it's hidden away and causes bugs. So this patch switches buildInstr to
returning a MachineInstrBuilder and adding *all* operands via addDef/addUse.
NFC.
llvm-svn: 277176
Mostly straightforward as we ignore addressing modes and just
use the base + unsigned immediate offset (always 0) variants.
This currently fails to select extloads because we have yet to
agree on a representation.
llvm-svn: 277171
Instead of an ad-hoc collection of "buildInstr" functions with varying numbers
of registers, this uses variadic templates to provide for as many regs as
needed!
Also make IRtranslator use new "buildBr" function instead of some weird generic
one that no-one else would really use.
llvm-svn: 276762
This adds LLVM's 3 main cast instructions (inttoptr, ptrtoint, bitcast) to the
IRTranslator. The first two are direct translations (with 2 MachineInstr types
each). Since LLT discards information, a bitcast might become trivial and we
emit a COPY in those cases instead.
llvm-svn: 276690
This adds the actual MachineLegalizeHelper to do the work and a trivial pass
wrapper that legalizes all instructions in a MachineFunction. Currently the
only transformation supported is splitting up a vector G_ADD into one acting on
smaller vectors.
llvm-svn: 276461
This should be all the low-level instruction selection needs to determine how
to implement an operation, with the remaining context taken from the opcode
(e.g. G_ADD vs G_FADD) or other flags not based on type (e.g. fast-math).
llvm-svn: 276158
We can freeze the registers after the MachineFrameInfo has been configured (by
telling it about calls, inline asm, ...). This doesn't happen at all yet, but
will be part of IR translation.
Fixes -verify-machineinstrs assertion.
llvm-svn: 275221
For complex rewrittings, which do not occur currently, the related
machine instruction may have been deleted in the process. Therefore, do
not try to print it after the mapping is applied.
llvm-svn: 272209
Refactor the code so that we do not compute in two different places the
end iterator for the range of new virtual registers for a given operand.
Although this refactoring was intended as NFC, this is not the case
because it actually fixes a bug where we were returning a range off by 1
(too long). Right now, this could not result in an actual bug because we
were accessing this range via the BreakDown size of the related operand.
llvm-svn: 272208
When repairing with a copy, instead of accounting for the cost of that
copy and actually inserting it, we may be able to use an alternative
source for the register to repair and just use it.
Make sure this is documented, so that we consider that opportunity at
some point.
llvm-svn: 272176
Now, the target will be able to provide its how implementation to remap
an instruction. This open the way to crazier optimizations, but to
beginning with, we will be able to handle something else than the
default mapping.
llvm-svn: 272165
When the command line option is set, it overrides any thing that the
target may have set. The rationale is that we get what we asked for.
Options are respectively regbankselect-fast and regbankselect-greedy for
fast and greedy mode.
llvm-svn: 272158
repairing.
Copies are easy because we repair only when there is a mismatch. For
non-copy repairing, i.e., cases that involves breaking down or gathering
up the value, one of the operand may not have a register bank yet. Thus,
derivate a cost from that, requires more work.
llvm-svn: 272157
The cost of a copy may be different based on how many bits we have to
copy around. E.g., a 8-bit copy may be different than a 32-bit copy.
llvm-svn: 272084
Prior to this patch, we were using 1 for all the repairing costs.
Now, we use the information from the target to get this information.
llvm-svn: 270304
The Fast mode takes the first mapping, the greedy mode loops over all
the possible mapping for an instruction and choose the cheaper one.
Test case will come with target specific code, since we currently do not
have instructions that have several mappings.
llvm-svn: 270249
computeMapping.
Computing the cost of a mapping takes some time.
Since in Fast mode, the cost is irrelevant, just spare some cycles by not
computing it.
In Greedy mode, we need to choose the best cost, that means that when
the local cost gets more expensive than the best cost, we can stop
computing the repairing and cost for the current mapping.
llvm-svn: 270245
The previous choice of the insertion points for repairing was
straightfoward but may introduce some basic block or edge splitting. In
some situation this is something we can avoid.
For instance, when repairing a phi argument, instead of placing the
repairing on the related incoming edge, we may move it to the previous
block, before the terminators. This is only possible when the argument
is not defined by one of the terminator.
llvm-svn: 270232
an instruction.
Use the previously introduced RepairingPlacement class to split the code
computing the repairing placement from the code doing the actual
placement. That way, we will be able to consider different placement and
then, only apply the best one.
llvm-svn: 270168
When assigning the register banks we may have to insert repairing code
to move already assigned values accross register banks.
Introduce a few helper classes to keep track of what is involved in the
repairing of an operand:
- InsertPoint and its derived classes record the positions, in the CFG,
where repairing has to be inserted.
- RepairingPlacement holds all the insert points for the repairing of an
operand plus the kind of action that is required to do the repairing.
This is going to be used to keep track of how the repairing should be
done, while comparing different solutions for an instruction. Indeed, we
will need the repairing placement to capture the cost of a solution and
we do not want to compute it a second time when we do the actual
repairing.
llvm-svn: 270167
register bank twice.
Prior to this change, we were checking if the assignment for the current
machine operand was matching, then we would check if the mismatch
requires to insert repair code.
We actually already have this information from the first check, so just
pass it along.
NFCI.
llvm-svn: 270166
This helper class will be used to represent the cost of mapping an
instruction to a specific register bank.
The particularity of these costs is that they are mostly local, thus the
frequency of the basic block is irrelevant. However, for few
instructions (e.g., phis and terminators), the cost may be non-local and
then, we need to account for the frequency of the involved basic blocks.
This will be used by the greedy mode I am working on.
llvm-svn: 270163
Instead of holding a mask, hold two value: the start index and the
length of the mapping. This is a more compact representation, although
less powerful. That being said, arbitrary masks would not have worked
for the generic so do not allow them in the first place.
llvm-svn: 267025
Although repairing definitions is not mandatory for correctness (only
phis would be impacted because of the RPO traversal), not repairing
might go against the cost model. Therefore, just repair when it is
possible.
llvm-svn: 266025
When assigning the register banks of an instruction, it is best to know
all the constraints of the input to have a good idea of how this will
impact the cost of the whole function.
llvm-svn: 265812
Do not give that much importance to the current register bank of an
operand. This is likely just a side effect of the current execution and
it is properly wise to prefer a register bank that can be extracted from
the information available statically (like encoding constraints and
type).
llvm-svn: 265810
Add verbose information when checking if the current and the desired
register banks match.
Detail what happens when we assign a register bank.
llvm-svn: 265804
specific type.
This will be used to find the default mapping of the instruction.
Also, this information is recorded, instead of computed, because it is
expensive from a type to know which register bank maps it.
Indeed, we need to iterate through all the register classes of all the
register banks to find the one that maps the given type.
llvm-svn: 265736
from a register.
On top of duplicating the logic, it was buggy! It would assert on
physical registers, since MachineRegisterInfo does not have any
information regarding register classes/banks for them.
llvm-svn: 265727
The pass walk through the machine function and assign the register banks
using the default mapping. In other words, there is no attempt to reduce
cross register copies.
llvm-svn: 265707
the mapping of an instruction on register bank.
For most instructions, it is possible to guess the mapping of the
instruciton by using the encoding constraints.
It remains instructions without encoding constraints.
For copy-like instructions, we try to propagate the information we get
from the other operands. Otherwise, the target has to give this
information.
llvm-svn: 265703
helper class.
The default constructor creates invalid (isValid() == false) instances
and may be used to communicate that a mapping was not found.
llvm-svn: 265699
getInstrMapping.
This implementation requires that the target implemented
getRegBankFromRegClass.
Indeed, the implementation uses the register classes for the encoding
constraints for the instructions to deduce the mapping of a value.
llvm-svn: 265624
This will be used by the register bank select pass to assign register banks
for generic virtual registers.
This was originally committed as r265573 but broke at least one windows bot.
The problem with the windows bot was that it was using a copy constructor for
the InstructionMappings class and could not synthesize it. Actually, the fact
that this class is not copy constructable is expected and the compiler should
use the move assignment constructor. Marking the problematic assignment
explicitly as using the move constructor has its own problems.
Indeed, with recent clang we get a warning that we may prevent the elision of
the copy by the compiler. A proper fix for both compilers would be to change the
API of getPossibleInstrMapping to take a InstructionMappings as input/output
parameter. This does not feel natural and since GISel is not used on windows
yet, I chose to workaround the problem by not compiling the problematic code on
windows.
llvm-svn: 265604
instruction on a register bank. This will be used by the register bank select
pass to assign register banks for generic virtual registers." and the follow-on
commits while I find out a way to fix the win7 bot:
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/19882
This reverts commit r265578, r265581, r265584, and r265585.
llvm-svn: 265587
helper class.
The default constructor creates invalid (isValid() == false) instances
and may be used to communicate that a mapping was not found.
llvm-svn: 265581
The method checks that the value is fully defined accross the different partial
mappings and that the partial mappings are compatible between each other.
llvm-svn: 265556
As part of the TRI argument of addRegBankCoverage we already have access to
the TargetRegisterClass through the ID of that register class.
Therefore, there is no point in needing a TargetRegisterClass instance,
the ID is enough to get to it.
llvm-svn: 265487
Change the default constructor to create invalid object.
The target will have to properly initialize the register banks before
using them.
llvm-svn: 265460
Original message:
Get rid of the ifdefs in TargetLowering.
Introduce a new API used only by GlobalISel: CallLowering.
This API will contain target hooks dedicated to call lowering.
llvm-svn: 260998
The rational for this change is that LLVMBuild cannot express conditional
dependencies. Therefore, when we start optionally using GlobalISel library for
say AArch64, without that change, all the tools that use the AArch64 library
would need to explicitly link with GlobalISel when we ask for it.
This does not scale.
Instead, we will set the dependencies between the target and GlobalISel and if
we did not ask to build GlobalISel, the library will just be empty.
Thanks to Chris Bieneman and Mehdi Animi for the idea.
llvm-svn: 260566
Summary:
Mark the LLVMGlobalISel library as optional in
LLVMBuild.txt, since the library is only built
if LLVM_BUILD_GLOBAL_ISEL is set. Without doing
this, llvm-config includes the library in the
list of components regardless of whether it's
built, and then will error out when asked for
the library names/paths.
Reviewers: qcolombet
Subscribers: joker.eph, llvm-commits, vkalintiris
Differential Revision: http://reviews.llvm.org/D16386
llvm-svn: 258379
This patch adds the necessary plumbing to cmake to build the sources related to
GlobalISel.
To build the sources related to GlobalISel, we need to add -DBUILD_GLOBAL_ISEL=ON.
By default, this is OFF, thus GlobalISel sources will not impact people that do
not explicitly opt-in.
Differential Revision: http://reviews.llvm.org/D15983
llvm-svn: 258344
Tim Northover