Summary:
Preserve call site info for duplicated instructions. We copy over the
call site info in CloneMachineInstrBundle to avoid repeated calls to
copyCallSiteInfo in CloneMachineInstr.
(Alternatively, we could copy call site info higher up the stack, e.g.
into TargetInstrInfo::duplicate, or even into individual backend passes.
However, I don't see how that would be safer or more general than the
current approach.)
Reviewers: aprantl, djtodoro, dstenb
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77685
Summary:
When narrowing G_IMPLICIT_DEF where the original size is not a multiple
of the narrow size, emit a smaller G_IMPLICIT_DEF and use G_ANYEXT.
To prevent a potential endless loop in the legalizer, the condition
to combine G_ANYEXT(G_IMPLICIT_DEF) is changed from isInstUnsupported
to !isInstLegal, since in this case the combine is only valid if
consequent legalization of the newly combined G_IMPLICIT_DEF does not
introduce G_ANYEXT due to narrowing.
Although this legalization for G_IMPLICIT_DEF would also be valid for
the general case, it actually caused a lot of code regressions when
tried due to superfluous COPYs and combines not getting hit anymore.
Reviewers: dsanders, aemerson, volkan, arsenm, aditya_nandakumar
Reviewed By: arsenm
Subscribers: jvesely, nhaehnle, kerbowa, wdng, rovka, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76598
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790
Reviewers: courbet
Subscribers: jyknight, sdardis, nemanjai, hiraditya, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, jfb, PkmX, jocewei, Jim, lenary, s.egerton, pzheng, sameer.abuasal, apazos, luismarques, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77059
Summary:
The existing helper function can only create a libcall to functions available in
RTLIB. Add a helper function that can create a libcall to a given function name
using the provided calling convention.
Reviewers: aditya_nandakumar, t.p.northover, rovka, arsenm, dsanders
Reviewed By: arsenm
Subscribers: wdng, hiraditya, volkan, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76845
For some operations, the type is unimportant and only the number of
bits matters. For example I don't want to treat <4 x s8> as a legal
type, but I also don't want to decompose loads of this into smaller
pieces to get legal register types.
On AMDGPU in SelectionDAG, we legalize a number of operations (most
notably load and store) by coercing all types to vectors of i32. For
GlobalISel, I'm trying very hard to avoid doing this for every type,
but I don't think this strategy can be completely avoided. I'm trying
to avoid bitcasts for any legitimately legal type we can operate on,
since the intervening bitcasts have proven to be a hassle.
For loads, I think I can get away without ever casting the result
type, and handling any arbitrary bitwidth during selection (I will
eventually want new tablegen support to help with this, rather than
having to add every possible type as legal). The unmerge required to
do anything with the value should expand to the expected shifts. This
is trickier for stores, since it would now require handling a wide
array of truncates during selection which I don't want.
Future potentially interesting case are for vector indexing, where
sub-dword type should be indexed in s32 pieces.
Summary:
Widening G_UNMERGE_VALUES to a type which is larger than the
original source type is the same as widening it to the same
type as the source type: in both cases, G_UNMERGE_VALUES has
to be replaced with bit arithmetic which. Although the arithmetic
itself is independent of whether the source type is smaller
or equal to the widen type, widening the source type to the
widen type should result in less artifacts being emitted,
since this is the type that the user explicitly requested.
Reviewers: arsenm, dsanders, aemerson, aditya_nandakumar
Reviewed By: arsenm, dsanders
Subscribers: jvesely, wdng, nhaehnle, rovka, hiraditya, volkan, kerbowa, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76494
I used the implementation for floor instead of round. It also turns
out the OpenCL builtin library wasn't using the round builtin, but
implemented the expanded form.
Summary: When narrowing a scalar G_EXTRACT where the destination lines up perfectly with a single result of the emitted G_UNMERGE_VALUES a COPY should be emitted instead of unconditionally trying to emit a G_MERGE_VALUES.
Reviewers: arsenm, dsanders
Reviewed By: arsenm
Subscribers: wdng, rovka, hiraditya, volkan, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D75743
Way back in D24994, the combination of LexicalScopes::dominates and
LiveDebugValues was identified as having worst-case quadratic complexity,
but it wasn't triggered by any code path at the time. I've since run into a
scenario where this occurs, in a very large basic block where large numbers
of inlined DBG_VALUEs are present.
The quadratic-ness comes from LiveDebugValues::join calling "dominates" on
every variable location, and LexicalScopes::dominates potentially touching
every instruction in a block to test for the presence of a scope. We have,
however, already computed the presence of scopes in blocks, in the
"InstrRanges" of each scope. This patch switches the dominates method to
examine whether a block is present in a scope's InsnRanges, avoiding
walking through the whole block.
At the same time, fix getMachineBasicBlocks to account for the fact that
InsnRanges can cover multiple blocks, and add some unit tests, as Lexical
Scopes didn't have any.
Differential revision: https://reviews.llvm.org/D73725
Unlike what I claimed in my previous commit. The caching is
actually not NFC on PHIs.
When we put a big enough max depth, we end up simulating loops.
The cache is effectively cutting the simulation short and we
get less information as a result.
E.g.,
```
v0 = G_CONSTANT i8 0xC0
jump
v1 = G_PHI i8 v0, v2
v2 = G_LSHR i8 v1, 1
```
Let say we want the known bits of v1.
- With cache:
Set v1 cache to we know nothing
v1 is v0 & v2
v0 gives us 0xC0
v2 gives us known bits of v1 >> 1
v1 is in the cache
=> v1 is 0, thus v2 is 0x80
Finally v1 is v0 & v2 => 0x80
- Without cache and enough depth to do two iteration of the loop:
v1 is v0 & v2
v0 gives us 0xC0
v2 gives us known bits of v1 >> 1
v1 is v0 & v2
v0 is 0xC0
v2 is v1 >> 1
Reach the max depth for v1...
unwinding
v1 is know nothing
v2 is 0x80
v0 is 0xC0
v1 is 0x80
v2 is 0xC0
v0 is 0xC0
v1 is 0xC0
Thus now v1 is 0xC0 instead of 0x80.
I've added a unittest demonstrating that.
NFC
When analyzing PHIs, we gather the known bits for every operand and
merge them together to get the known bits of the result of the PHI.
It is not unusual that merging the information leads to know nothing
on the result (e.g., phi a: i8 3, b: i8 unknown, ..., after looking at the
second argument we know we will know nothing on the result), thus, as
soon as we reach that state, stop analyzing the following operand (i.e.,
on the previous example, we won't process anything after looking at `b`).
This improves compile time in particular with PHIs with a large number
of operands.
NFC.
Allows more flexible use of buildMerge in places where
use operands are available as SrcOp since it does not
require explicit conversion to Register.
Simplify code with new buildMerge.
Differential Revision: https://reviews.llvm.org/D74223
The type passed to lower was invalid, so I'm not sure how this was
even working before. The source and destination type also do not have
to match, so make sure to use the right ones.
The legalizer produces a lot of these, and they make reading legalized
MIR annoying. For some reason, this does seem to sometimes introduce
copies of implicit def, which is dumb.
Teach the GISelKnowBits analysis how to deal with PHI operations.
PHIs are essentially COPYs happening on edges, so we can just reuse
the code for COPY.
This is NFC COPY-wise has we leave Depth untouched when calling
computeKnownBitsImpl for COPYs, like it was before this patch.
Increasing Depth is however required for PHIs as they may loop back to
themselves and we would end up in an infinite loop if we were not
increasing Depth.
Differential Revision: https://reviews.llvm.org/D73317
Summary:
Added MIRFormatter for target specific MIR formating and parsing with
immediate and custom pseudo source values. Target machine can subclass
MIRFormatter and implement custom logic for printing and parsing
immediate and custom pseudo source values for better readability.
* Target specific immediate mnemonic need to start with "." follows by
identifier string. When MIR parser sees immediate it will call target
specific parsing function.
* Custom pseudo source value need to start with custom follows by
double-quoted string. MIR parser will pass the quoted string to target
specific PSV parsing function.
* MIRFormatter have 2 helper functions to facilitate LLVM value printing
and parsing for custom PSV if they refers LLVM values.
Patch by Peng Guo
Reviewers: dsanders, arsenm
Reviewed By: dsanders
Subscribers: wdng, jvesely, nhaehnle, hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69836
Summary:
Added MIRFormatter for target specific MIR formating and parsing with
immediate and custom pseudo source values. Target machine can subclass
MIRFormatter and implement custom logic for printing and parsing
immediate and custom pseudo source values for better readability.
* Target specific immediate mnemonic need to start with "." follows by
identifier string. When MIR parser sees immediate it will call target
specific parsing function.
* Custom pseudo source value need to start with custom follows by
double-quoted string. MIR parser will pass the quoted string to target
specific PSV parsing function.
* MIRFormatter have 2 helper functions to facilitate LLVM value printing
and parsing for custom PSV if they refers LLVM values.
Reviewers: dsanders, arsenm
Reviewed By: dsanders
Subscribers: wdng, jvesely, nhaehnle, hiraditya, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69836
Legalization algorithm is complicated by two facts:
1) While regular instructions should be possible to legalize in
an isolated, per-instruction, context-free manner, legalization
artifacts can only be eliminated in pairs, which could be deeply, and
ultimately arbitrary nested: { [ () ] }, where which paranthesis kind
depicts an artifact kind, like extend, unmerge, etc. Such structure
can only be fully eliminated by simple local combines if they are
attempted in a particular order (inside out), or alternatively by
repeated scans each eliminating only one innermost pair, resulting in
O(n^2) complexity.
2) Some artifacts might in fact be regular instructions that could (and
sometimes should) be legalized by the target-specific rules. Which
means failure to eliminate all artifacts on the first iteration is
not a failure, they need to be tried as instructions, which may
produce more artifacts, including the ones that are in fact regular
instructions, resulting in a non-constant number of iterations
required to finish the process.
I trust the recently introduced termination condition (no new artifacts
were created during as-a-regular-instruction-retrial of artifacts not
eliminated on the previous iteration) to be efficient in providing
termination, but only performing the legalization in full if and only if
at each step such chains of artifacts are successfully eliminated in
full as well.
Which is currently not guaranteed, as the artifact combines are applied
only once and in an arbitrary order that has to do with the order of
creation or insertion of artifacts into their worklist, which is a no
particular order.
In this patch I make a small change to the artifact combiner, making it
to re-insert into the worklist immediate (modulo a look-through copies)
artifact users of each vreg that changes its definition due to an
artifact combine.
Here the first scan through the artifacts worklist, while not
being done in any guaranteed order, only needs to find the innermost
pair(s) of artifacts that could be immediately combined out. After that
the process follows def-use chains, making them shorter at each step, thus
combining everything that can be combined in O(n) time.
Reviewers: volkan, aditya_nandakumar, qcolombet, paquette, aemerson, dsanders
Reviewed By: aditya_nandakumar, paquette
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71448
and introducing new unittests/CodeGen/GlobalISel/LegalizerTest.cpp
relying on it to unit test the entire legalizer algorithm (including the
top-level main loop).
See also https://reviews.llvm.org/D71448
* Implements scalable size queries for MVTs, split out from D53137.
* Contains a fix for FindMemType to avoid using scalable vector type
to contain non-scalable types.
* Explicit casts for several places where implicit integer sign
changes or promotion from 32 to 64 bits caused problems.
* CodeGenDAGPatterns will treat scalable and non-scalable vector types
as different.
Reviewers: greened, cameron.mcinally, sdesmalen, rovka
Reviewed By: rovka
Differential Revision: https://reviews.llvm.org/D66871
Summary:
After D70211, Pass.h does not include InitializePasses.h anymore, so
these files need to include InitializePasses.h directly.
Reviewers: rnk
Subscribers: MatzeB, mehdi_amini, zzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70217
Summary:
Fixes some things from original commit at https://reviews.llvm.org/D69136. The main
change is that the heap alloc marker is always stored as ExtraInfo in the machine
instruction instead of in the PointerSumType because it cannot hold more than
4 pointer types.
Add instruction marker to MachineInstr ExtraInfo. This does almost the
same thing as Pre/PostInstrSymbols, except that it doesn't create a label until
printing instructions. This allows for labels to be put around instructions that
are deleted/duplicated somewhere.
Use this marker to track heap alloc site call instructions.
Reviewers: rnk
Subscribers: MatzeB, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69536
Summary:
Add instruction marker to MachineInstr ExtraInfo. This does almost the
same thing as Pre/PostInstrSymbols, except that it doesn't create a label until
printing instructions. This allows for labels to be put around instructions that
are deleted/duplicated somewhere.
Also undo the workaround in r375137.
Reviewers: rnk
Subscribers: MatzeB, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D69136
Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790
Reviewers: courbet
Subscribers: jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, sbc100, jgravelle-google, hiraditya, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, jsji, Jim, lenary, s.egerton, pzheng, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68993
llvm-svn: 375084
After r368065, all the tests using GISelMITest must call setUp() before
doing anything, otherwise the TargetMachine is not going to be set up.
A few tests added after that commit were not doing that and ended up
testing effectively nothing.
Fix the setup of all the tests and fix the failing tests.
llvm-svn: 374595
Teach buildMerge how to deal with scalar to vector kind of requests.
Prior to this patch, buildMerge would issue either a G_MERGE_VALUES
when all the vregs are scalars or a G_CONCAT_VECTORS when the destination
vreg is a vector.
G_CONCAT_VECTORS was actually not the proper instruction when the source
vregs were scalars and the compiler would assert that the sources must
be vectors. Instead we want is to issue a G_BUILD_VECTOR when we are
in this situation.
This patch fixes that.
llvm-svn: 374588
In GISel we have both G_CONSTANT and G_FCONSTANT, but because
in GISel we don't really have a concept of Float vs Int value
the only difference between the two is where the data originates
from.
What both G_CONSTANT and G_FCONSTANT return is just a bag of bits
with the constant representation in it.
By making getConstantVRegVal() return G_FCONSTANTs bit representation
as well we allow ConstantFold and other things to operate with
G_FCONSTANT.
Adding tests that show ConstantFolding to work on mixed G_CONSTANT
and G_FCONSTANT sources.
Differential Revision: https://reviews.llvm.org/D68739
llvm-svn: 374458
* Adds a TypeSize struct to represent the known minimum size of a type
along with a flag to indicate that the runtime size is a integer multiple
of that size
* Converts existing size query functions from Type.h and DataLayout.h to
return a TypeSize result
* Adds convenience methods (including a transparent conversion operator
to uint64_t) so that most existing code 'just works' as if the return
values were still scalars.
* Uses the new size queries along with ElementCount to ensure that all
supported instructions used with scalable vectors can be constructed
in IR.
Reviewers: hfinkel, lattner, rkruppe, greened, rovka, rengolin, sdesmalen
Reviewed By: rovka, sdesmalen
Differential Revision: https://reviews.llvm.org/D53137
llvm-svn: 374042
Summary:
Remove use of FileCheckPatternContext and FileCheckString concrete types
from FileCheck API to allow moving it and the other implementation only
only declarations into a private header file.
Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D68186
llvm-svn: 373211
Now that we look through copies, it's possible to visit registers that
have a register class constraint but not a type constraint. Avoid looking
through copies when this occurs as the SrcReg won't be able to determine
it's bit width or any known bits.
Along the same lines, if the initial query is on a register that doesn't
have a type constraint then the result is a default-constructed KnownBits,
that is, a 1-bit fully-unknown value.
llvm-svn: 371116
Now that we've moved to C++14, we no longer need the llvm::make_unique
implementation from STLExtras.h. This patch is a mechanical replacement
of (hopefully) all the llvm::make_unique instances across the monorepo.
llvm-svn: 369013
https://reviews.llvm.org/D66039
We were using getIndexSize instead of getIndexSizeInBits().
Added test case for G_PTRTOINT and G_INTTOPTR.
llvm-svn: 368618
Summary:
Targets often have instructions that can sign-extend certain cases faster
than the equivalent shift-left/arithmetic-shift-right. Such cases can be
identified by matching a shift-left/shift-right pair but there are some
issues with this in the context of combines. For example, suppose you can
sign-extend 8-bit up to 32-bit with a target extend instruction.
%1:_(s32) = G_SHL %0:_(s32), i32 24 # (I've inlined the G_CONSTANT for brevity)
%2:_(s32) = G_ASHR %1:_(s32), i32 24
%3:_(s32) = G_ASHR %2:_(s32), i32 1
would reasonably combine to:
%1:_(s32) = G_SHL %0:_(s32), i32 24
%2:_(s32) = G_ASHR %1:_(s32), i32 25
which no longer matches the special case. If your shifts and extend are
equal cost, this would break even as a pair of shifts but if your shift is
more expensive than the extend then it's cheaper as:
%2:_(s32) = G_SEXT_INREG %0:_(s32), i32 8
%3:_(s32) = G_ASHR %2:_(s32), i32 1
It's possible to match the shift-pair in ISel and emit an extend and ashr.
However, this is far from the only way to break this shift pair and make
it hard to match the extends. Another example is that with the right
known-zeros, this:
%1:_(s32) = G_SHL %0:_(s32), i32 24
%2:_(s32) = G_ASHR %1:_(s32), i32 24
%3:_(s32) = G_MUL %2:_(s32), i32 2
can become:
%1:_(s32) = G_SHL %0:_(s32), i32 24
%2:_(s32) = G_ASHR %1:_(s32), i32 23
All upstream targets have been configured to lower it to the current
G_SHL,G_ASHR pair but will likely want to make it legal in some cases to
handle their faster cases.
To follow-up: Provide a way to legalize based on the constant. At the
moment, I'm thinking that the best way to achieve this is to provide the
MI in LegalityQuery but that opens the door to breaking core principles
of the legalizer (legality is not context sensitive). That said, it's
worth noting that looking at other instructions and acting on that
information doesn't violate this principle in itself. It's only a
violation if, at the end of legalization, a pass that checks legality
without being able to see the context would say an instruction might not be
legal. That's a fairly subtle distinction so to give a concrete example,
saying %2 in:
%1 = G_CONSTANT 16
%2 = G_SEXT_INREG %0, %1
is legal is in violation of that principle if the legality of %2 depends
on %1 being constant and/or being 16. However, legalizing to either:
%2 = G_SEXT_INREG %0, 16
or:
%1 = G_CONSTANT 16
%2:_(s32) = G_SHL %0, %1
%3:_(s32) = G_ASHR %2, %1
depending on whether %1 is constant and 16 does not violate that principle
since both outputs are genuinely legal.
Reviewers: bogner, aditya_nandakumar, volkan, aemerson, paquette, arsenm
Subscribers: sdardis, jvesely, wdng, nhaehnle, rovka, kristof.beyls, javed.absar, hiraditya, jrtc27, atanasyan, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61289
llvm-svn: 368487
https://reviews.llvm.org/D65698
This adds a KnownBits analysis pass for GISel. This was done as a
pass (compared to static functions) so that we can add other features
such as caching queries(within a pass and across passes) in the future.
This patch only adds the basic pass boiler plate, and implements a lazy
non caching knownbits implementation (ported from SelectionDAG). I've
also hooked up the AArch64PreLegalizerCombiner pass to use this - there
should be no compile time regression as the analysis is lazy.
llvm-svn: 368065
Adds a two way mapping between the scalable vector IR type and
corresponding SelectionDAG ValueTypes.
Reviewers: craig.topper, jeroen.dobbelaere, fhahn, rengolin, greened, rovka
Reviewed By: greened
Differential Revision: https://reviews.llvm.org/D47770
llvm-svn: 367832
Extract the sources to the GCD of the original size and target size,
padding with implicit_def as necessary.
Also fix the case where the requested source type is wider than the
original result type. This was ignoring the type, and just using the
destination. Do the operation in the requested type and truncate back.
llvm-svn: 366367
Use an anyext to the requested type for the leftover operand to
produce a slightly wider type, and then truncate the final merge.
I have another implementation almost ready which handles arbitrary
widens, but I think it produces worse code in this example (which I
think is 90% due to not folding redundant copies or folding out
implicit_def users), so I wanted to add this as a baseline first.
llvm-svn: 366366
Avoids using a plain unsigned for registers throughoug codegen.
Doesn't attempt to change every register use, just something a little
more than the set needed to build after changing the return type of
MachineOperand::getReg().
llvm-svn: 364191
This was ignoring the flag on fneg, and using the source instruction's
flags. Also fixes tests missing from r358702.
Note the expansion itself isn't correct without nnan, but that should
be fixed separately.
llvm-svn: 363637
Over a year ago, MachineInstr gained a fourth boolean parameter that occurs
before the TII pointer. When this happened, several places started accidentally
passing TII into this boolean parameter instead of the TII parameter.
llvm-svn: 362312
We were hashing the string pointer, not the string, so two instructions
could be identical (isIdenticalTo), but have different hash codes.
This showed up as a very rare, non-deterministic assertion failure
rehashing a DenseMap constructed by MachineOutliner. So there's no
"real" testcase, just a unittest which checks that the hash function
behaves correctly.
I'm a little scared fixing this is going to cause a regression in
outlining or MachineCSE, but hopefully we won't run into any issues.
Differential Revision: https://reviews.llvm.org/D61975
llvm-svn: 362281
Summary:
Use KnownBits::computeForAddSub/computeForAddCarry
in SelectionDAG::computeKnownBits when doing value
tracking for addition/subtraction.
This should improve the precision of the known bits,
as we only used to make a simple estimate of known
zeroes. The KnownBits support functions are also
able to deduce bits that are known to be one in the
result.
Reviewers: spatel, RKSimon, nikic, lebedev.ri
Reviewed By: nikic
Subscribers: nikic, javed.absar, lebedev.ri, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D60460
llvm-svn: 358372
Because CodeGen can't depend on GlobalISel, we need a way to encapsulate the CSE
configs that can be passed between TargetPassConfig and the targets' custom
pass configs. This CSEConfigBase allows targets to create custom CSE configs
which is then used by the GISel passes for the CSEMIRBuilder.
This support will be used in a follow up commit to allow constant-only CSE for
-O0 compiles in D60580.
llvm-svn: 358368
These arrays are both keyed by CPU name and go into the same tablegenerated file. Merge them so we only need to store keys once.
This also removes a weird space saving quirk where we used the ProcDesc.size() to create to build an ArrayRef for ProcSched.
Differential Revision: https://reviews.llvm.org/D58939
llvm-svn: 355431
Summary:
Prior to r310876 one of our out-of-tree targets was enabling IPRA by modifying
the TargetOptions::EnableIPRA. This no longer works on current trunk since the
useIPRA() hook overrides any values that are set in advance. This patch adjusts
the behaviour of the hook so that API users and useIPRA() can both enable it
but useIPRA() cannot disable it if the API user already enabled it.
Reviewers: arsenm
Reviewed By: arsenm
Subscribers: wdng, mgorny, llvm-commits
Differential Revision: https://reviews.llvm.org/D38043
llvm-svn: 354692
This fixes two problems with CSE done in buildConstant. First, this
would hit an assert when used with a vector result type. Solve this by
allowing CSE on the vector elements, but not on the result vector for
now.
Second, this was also performing the CSE based on the input
ConstantInt pointer. The underlying buildConstant could potentially
convert the constant depending on the result type, giving in a
different ConstantInt*. Stop allowing the APInt and ConstantInt forms
from automatically casting to the result type to avoid any similar
problems in the future.
llvm-svn: 353077
The IR enforced limit for the address space is 24-bits, but LLT was
only using 23-bits. Additionally, the argument to the constructor was
truncating to 16-bits.
A similar problem still exists for the number of vector elements. The
IR enforces no limit, so if you try to use a vector with > 65535
elements the IRTranslator asserts in the LLT constructor.
llvm-svn: 352264
As noted in https://bugs.llvm.org/show_bug.cgi?id=36651, the specialization for
isPodLike<std::pair<...>> did not match the expectation of
std::is_trivially_copyable which makes the memcpy optimization invalid.
This patch renames the llvm::isPodLike trait into llvm::is_trivially_copyable.
Unfortunately std::is_trivially_copyable is not portable across compiler / STL
versions. So a portable version is provided too.
Note that the following specialization were invalid:
std::pair<T0, T1>
llvm::Optional<T>
Tests have been added to assert that former specialization are respected by the
standard usage of llvm::is_trivially_copyable, and that when a decent version
of std::is_trivially_copyable is available, llvm::is_trivially_copyable is
compared to std::is_trivially_copyable.
As of this patch, llvm::Optional is no longer considered trivially copyable,
even if T is. This is to be fixed in a later patch, as it has impact on a
long-running bug (see r347004)
Note that GCC warns about this UB, but this got silented by https://reviews.llvm.org/D50296.
Differential Revision: https://reviews.llvm.org/D54472
llvm-svn: 351701
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
https://reviews.llvm.org/D52803
This patch adds support to continuously CSE instructions during
each of the GISel passes. It consists of a GISelCSEInfo analysis pass
that can be used by the CSEMIRBuilder.
llvm-svn: 351283
Summary:
This allows us to register it with the MachineFunction delegate and be
notified automatically about erasure and creation of instructions. However,
we still need explicit notification for modifications such as those caused
by setReg() or replaceRegWith().
There is a catch with this though. The notification for creation is
delivered before any operands can be added. While appropriate for
scheduling combiner work. This is unfortunate for debug output since an
opcode by itself doesn't provide sufficient information on what happened.
As a result, the work list remembers the instructions (when debug output is
requested) and emits a more complete dump later.
Another nit is that the MachineFunction::Delegate provides const pointers
which is inconvenient since we want to use it to schedule future
modification. To resolve this GISelWorkList now has an optional pointer to
the MachineFunction which describes the scope of the work it is permitted
to schedule. If a given MachineInstr* is in this function then it is
permitted to schedule work to be performed on the MachineInstr's. An
alternative to this would be to remove the const from the
MachineFunction::Delegate interface, however delegates are not permitted
to modify the MachineInstr's they receive.
In addition to this, the observer has three interface changes.
* erasedInstr() is now erasingInstr() to indicate it is about to be erased
but still exists at the moment.
* changingInstr() and changedInstr() have been added to report changes
before and after they are made. This allows us to trace the changes
in the debug output.
* As a convenience changingAllUsesOfReg() and
finishedChangingAllUsesOfReg() will report changingInstr() and
changedInstr() for each use of a given register. This is primarily useful
for changes caused by MachineRegisterInfo::replaceRegWith()
With this in place, both combine rules have been updated to report their
changes to the observer.
Finally, make some cosmetic changes to the debug output and make Combiner
and CombinerHelp
Reviewers: aditya_nandakumar, bogner, volkan, rtereshin, javed.absar
Reviewed By: aditya_nandakumar
Subscribers: mgorny, rovka, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D52947
llvm-svn: 349167
Summary:
In addition to knowing that an instruction is changed. It's also useful to
know when it's about to change. For example, it might print the instruction so
you can track the changes in a debug log, it might remove it from some queue
while it's being worked on, or it might want to change several instructions as
a single transaction and act on all the changes at once.
Added changingInstr() to all existing uses of changedInstr()
Reviewers: aditya_nandakumar
Reviewed By: aditya_nandakumar
Subscribers: rovka, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D55623
llvm-svn: 348992
Summary:
There's little of interest that can be done to an already-erased instruction.
You can't inspect it, write it to a debug log, etc. It ought to be notification
that we're about to erase it. Rename the function to clarify the timing of the
event and reflect current usage.
Also fixed one case where we were trying to print an erased instruction.
Reviewers: aditya_nandakumar
Reviewed By: aditya_nandakumar
Subscribers: rovka, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D55611
llvm-svn: 348976
https://reviews.llvm.org/D55294
Previously MachineIRBuilder::buildInstr used to accept variadic
arguments for sources (which were either unsigned or
MachineInstrBuilder). While this worked well in common cases, it doesn't
allow us to build instructions that have multiple destinations.
Additionally passing in other optional parameters in the end (such as
flags) is not possible trivially. Also a trivial call such as
B.buildInstr(Opc, Reg1, Reg2, Reg3)
can be interpreted differently based on the opcode (2defs + 1 src for
unmerge vs 1 def + 2srcs).
This patch refactors the buildInstr to
buildInstr(Opc, ArrayRef<DstOps>, ArrayRef<SrcOps>)
where DstOps and SrcOps are typed unions that know how to add itself to
MachineInstrBuilder.
After this patch, most invocations would look like
B.buildInstr(Opc, {s32, DstReg}, {SrcRegs..., SrcMIBs..});
Now all the other calls (such as buildAdd, buildSub etc) forward to
buildInstr. It also makes it possible to build instructions with
multiple defs.
Additionally in a subsequent patch, we should make it possible to add
flags directly while building instructions.
Additionally, the main buildInstr method is now virtual and other
builders now only have to override buildInstr (for say constant
folding/cseing) is straightforward.
Also attached here (https://reviews.llvm.org/F7675680) is a clang-tidy
patch that should upgrade the API calls if necessary.
llvm-svn: 348815
https://reviews.llvm.org/D54980
This provides a standard API across GISel passes to observe and notify
passes about changes (insertions/deletions/mutations) to MachineInstrs.
This patch also removes the recordInsertion method in MachineIRBuilder
and instead provides method to setObserver.
Reviewed by: vkeles.
llvm-svn: 348406
We can now select CLZ via the TableGen'erated code, so support G_CTLZ
and G_CTLZ_ZERO_UNDEF throughout the pipeline for types <= s32.
Legalizer:
If the CLZ instruction is available, use it for both G_CTLZ and
G_CTLZ_ZERO_UNDEF. Otherwise, use a libcall for G_CTLZ_ZERO_UNDEF and
lower G_CTLZ in terms of it.
In order to achieve this we need to add support to the LegalizerHelper
for the legalization of G_CTLZ_ZERO_UNDEF for s32 as a libcall (__clzsi2).
We also need to allow lowering of G_CTLZ in terms of G_CTLZ_ZERO_UNDEF
if that is supported as a libcall, as opposed to just if it is Legal or
Custom. Due to a minor refactoring of the helper function in charge of
this, we will also allow the same behaviour for G_CTTZ and G_CTPOP.
This is not going to be a problem in practice since we don't yet have
support for treating G_CTTZ and G_CTPOP as libcalls (not even in
DAGISel).
Reg bank select:
Map G_CTLZ to GPR. G_CTLZ_ZERO_UNDEF should not make it to this point.
Instruction select:
Nothing to do.
llvm-svn: 347545
This will hold flags specific to subprograms. In the future
we could potentially free up scarce bits in DIFlags by moving
subprogram-specific flags from there to the new flags word.
This patch does not change IR/bitcode formats, that will be
done in a follow-up.
Differential Revision: https://reviews.llvm.org/D54597
llvm-svn: 347239
MachineModuleInfo can only be used in code using lib/CodeGen, hence we
can keep a more specific reference to LLVMTargetMachine rather than just
TargetMachine around.
llvm-svn: 346182
These methods were just wrappers around getNode with additional asserts (identical and repeated 3 times). But getNode already has a switch that can be used to hold these asserts that allows them to be shared for all 3 opcodes. This also enables checking on the places that create these nodes without using the wrappers.
The rest of the patch is just changing all callers to use getNode directly.
llvm-svn: 346087
This reverts commit d1341152d91398e9a882ba2ee924147ea2f9b589.
This patch originally made use of Nested MachineIRBuilder buildInstr
calls, and since order of argument processing is not well defined, the
instructions were built slightly in a different order (still correct).
I've removed the nested buildInstr calls to have a defined order now.
Patch was tested by Mikael.
llvm-svn: 340309
Summary:
The accelerator tables use the debug_str section to store their strings.
However, they do not support the indirect method of access that is
available for the debug_info section (DW_FORM_strx et al.).
Currently our code is assuming that all strings can/will be referenced
indirectly, and puts all of them into the debug_str_offsets section.
This is generally true for regular (unsplit) dwarf, but in the DWO case,
most of the strings in the debug_str section will only be used from the
accelerator tables. Therefore the contents of the debug_str_offsets
section will be largely unused and bloating the main executable.
This patch rectifies this by teaching the DwarfStringPool to
differentiate between strings accessed directly and indirectly. When a
user inserts a string into the pool it has to declare whether that
string will be referenced directly or not. If at least one user requsts
indirect access, that string will be assigned an index ID and put into
debug_str_offsets table. Otherwise, the offset table is skipped.
This approach reduces the overall binary size (when compiled with
-gdwarf-5 -gsplit-dwarf) in my tests by about 2% (debug_str_offsets is
shrunk by 99%).
Reviewers: probinson, dblaikie, JDevlieghere
Subscribers: aprantl, mgrang, llvm-commits
Differential Revision: https://reviews.llvm.org/D49493
llvm-svn: 339122
building.
https://reviews.llvm.org/D45067
This change attempts to do two things:
1) It separates out the state that is stored in the
MachineIRBuilder(InsertionPt, MF, MRI, InsertFunction etc) into a
separate object called MachineIRBuilderState.
2) Add the ability to constant fold operations while building instructions
(optionally). MachineIRBuilder is now refactored into a MachineIRBuilderBase
which contains lots of non foldable build methods and their implementation.
Instructions which can be constant folded/transformed are now in a class
called FoldableInstructionBuilder which uses CRTP to use the implementation
of the derived class for buildBinaryOps. Additionally buildInstr in the derived
class can be used to implement other kinds of transformations.
Also because of separation of state, given a MachineIRBuilder in an API,
if one wishes to use another MachineIRBuilder, a new one can be
constructed from the state locally. For eg,
void doFoo(MachineIRBuilder &B) {
MyCustomBuilder CustomB(B.getState());
// Use CustomB for building.
}
reviewed by : aemerson
llvm-svn: 329596
Currently EVT is in the IR layer only because of Function.cpp needing a very small piece of the functionality of EVT::getEVTString(). The rest of EVT is used in codegen making CodeGen a better place for it.
The previous code converted a Type* to EVT and then called getEVTString. This was only expected to handle the primitive types from Type*. Since there only a few primitive types, we can just print them as strings directly.
Differential Revision: https://reviews.llvm.org/D45017
llvm-svn: 328806
This is used by llvm tblgen as well as by LLVM Targets, so the only
common place is Support for now. (maybe we need another target for these
sorts of things - but for now I'm at least making them correct & we can
make them better if/when people have strong feelings)
llvm-svn: 328395
Added helpers to build G_FCONSTANT, along with matching ConstantFP and
unit tests for the same.
Sample usage.
auto MIB = Builder.buildFConstant(s32, 0.5); // Build IEEESingle
For Matching the above
const ConstantFP* Tmp;
mi_match(DstReg, MRI, m_GFCst(Tmp));
https://reviews.llvm.org/D44128
reviewed by: volkan
llvm-svn: 327152
Summary:
Fabs is a common floating-point operation, especially for some expansions. This patch adds
a new generic opcode for llvm.fabs.* intrinsic in order to avoid building/matching this intrinsic.
Reviewers: qcolombet, aditya_nandakumar, dsanders, rovka
Reviewed By: aditya_nandakumar
Subscribers: kristof.beyls, javed.absar, llvm-commits
Differential Revision: https://reviews.llvm.org/D43864
llvm-svn: 326749
The base case for any_of was incorrectly returning true. Also add test
case which uses m_any_of(preds...) where none of the predicates are
true.
llvm-svn: 325848
Summary:
This patch adds templated functions to MachineIRBuilder for some opcodes
and adds pattern matcher support for G_AND and G_OR.
Reviewers: aditya_nandakumar
Reviewed By: aditya_nandakumar
Subscribers: rovka, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D43309
llvm-svn: 325162
Discussed here:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120320.html
In preparation for adding support for named vregs we are changing the sigil for
physical registers in MIR to '$' from '%'. This will prevent name clashes of
named physical register with named vregs.
llvm-svn: 323922
Summary:
As discussed in D42244, we have difficulty describing the legality of some
operations. We're not able to specify relationships between types.
For example, declaring the following
setAction({..., 0, s32}, Legal)
setAction({..., 0, s64}, Legal)
setAction({..., 1, s32}, Legal)
setAction({..., 1, s64}, Legal)
currently declares these type combinations as legal:
{s32, s32}
{s64, s32}
{s32, s64}
{s64, s64}
but we currently have no means to say that, for example, {s64, s32} is
not legal. Some operations such as G_INSERT/G_EXTRACT/G_MERGE_VALUES/
G_UNMERGE_VALUES have relationships between the types that are currently
described incorrectly.
Additionally, G_LOAD/G_STORE currently have no means to legalize non-atomics
differently to atomics. The necessary information is in the MMO but we have no
way to use this in the legalizer. Similarly, there is currently no way for the
register type and the memory type to differ so there is no way to cleanly
represent extending-load/truncating-store in a way that can't be broken by
optimizers (resulting in illegal MIR).
It's also difficult to control the legalization strategy. We've added support
for legalizing non-power of 2 types but there's still some hardcoded assumptions
about the strategy. The main one I've noticed is that type0 is always legalized
before type1 which is not a good strategy for `type0 = G_EXTRACT type1, ...` if
you need to widen the container. It will converge on the same result eventually
but it will take a much longer route when legalizing type0 than if you legalize
type1 first.
Lastly, the definition of legality and the legalization strategy is kept
separate which is not ideal. It's helpful to be able to look at a one piece of
code and see both what is legal and the method the legalizer will use to make
illegal MIR more legal.
This patch adds a layer onto the LegalizerInfo (to be removed when all targets
have been migrated) which resolves all these issues.
Here are the rules for shift and division:
for (unsigned BinOp : {G_LSHR, G_ASHR, G_SDIV, G_UDIV})
getActionDefinitions(BinOp)
.legalFor({s32, s64}) // If type0 is s32/s64 then it's Legal
.clampScalar(0, s32, s64) // If type0 is <s32 then WidenScalar to s32
// If type0 is >s64 then NarrowScalar to s64
.widenScalarToPow2(0) // Round type0 scalars up to powers of 2
.unsupported(); // Otherwise, it's unsupported
This describes everything needed to both define legality and describe how to
make illegal things legal.
Here's an example of a complex rule:
getActionDefinitions(G_INSERT)
.unsupportedIf([=](const LegalityQuery &Query) {
// If type0 is smaller than type1 then it's unsupported
return Query.Types[0].getSizeInBits() <= Query.Types[1].getSizeInBits();
})
.legalIf([=](const LegalityQuery &Query) {
// If type0 is s32/s64/p0 and type1 is a power of 2 other than 2 or 4 then it's legal
// We don't need to worry about large type1's because unsupportedIf caught that.
const LLT &Ty0 = Query.Types[0];
const LLT &Ty1 = Query.Types[1];
if (Ty0 != s32 && Ty0 != s64 && Ty0 != p0)
return false;
return isPowerOf2_32(Ty1.getSizeInBits()) &&
(Ty1.getSizeInBits() == 1 || Ty1.getSizeInBits() >= 8);
})
.clampScalar(0, s32, s64)
.widenScalarToPow2(0)
.maxScalarIf(typeInSet(0, {s32}), 1, s16) // If type0 is s32 and type1 is bigger than s16 then NarrowScalar type1 to s16
.maxScalarIf(typeInSet(0, {s64}), 1, s32) // If type0 is s64 and type1 is bigger than s32 then NarrowScalar type1 to s32
.widenScalarToPow2(1) // Round type1 scalars up to powers of 2
.unsupported();
This uses a lambda to say that G_INSERT is unsupported when type0 is bigger than
type1 (in practice, this would be a default rule for G_INSERT). It also uses one
to describe the legal cases. This particular predicate is equivalent to:
.legalFor({{s32, s1}, {s32, s8}, {s32, s16}, {s64, s1}, {s64, s8}, {s64, s16}, {s64, s32}})
In terms of performance, I saw a slight (~6%) performance improvement when
AArch64 was around 30% ported but it's pretty much break even right now.
I'm going to take a look at constexpr as a means to reduce the initialization
cost.
Future work:
* Make it possible for opcodes to share rulesets. There's no need for
G_LSHR/G_ASHR/G_SDIV/G_UDIV to have separate rule and ruleset objects. There's
no technical barrier to this, it just hasn't been done yet.
* Replace the type-index numbers with an enum to get .clampScalar(Type0, s32, s64)
* Better names for things like .maxScalarIf() (clampMaxScalar?) and the vector rules.
* Improve initialization cost using constexpr
Possible future work:
* It's possible to make these rulesets change the MIR directly instead of
returning a description of how to change the MIR. This should remove a little
overhead caused by parsing the description and routing to the right code, but
the real motivation is that it removes the need for LegalizeAction::Custom.
With Custom removed, there's no longer a requirement that Custom legalization
change the opcode to something that's considered legal.
Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar, volkan, reames, bogner
Reviewed By: bogner
Subscribers: hintonda, bogner, aemerson, mgorny, javed.absar, kristof.beyls, llvm-commits
Differential Revision: https://reviews.llvm.org/D42251
llvm-svn: 323681
Summary:
The improvements to the LegalizerInfo discussed in D42244 require that
LegalizerInfo::LegalizeAction be available for use in other classes. As such,
it needs to be moved out of LegalizerInfo. This has been done separately to the
next patch to minimize the noise in that patch.
llvm-svn: 323669
Summary:
`getAction(const InstrAspect &) const` breaks encapsulation by exposing
the smaller components that are used to decide how to legalize an
instruction.
This is a problem because we need to change the implementation of
LegalizerInfo so that it's able to describe particular type combinations
rather than just cartesian products of types.
For example, declaring the following
setAction({..., 0, s32}, Legal)
setAction({..., 0, s64}, Legal)
setAction({..., 1, s32}, Legal)
setAction({..., 1, s64}, Legal)
currently declares these type combinations as legal:
{s32, s32}
{s64, s32}
{s32, s64}
{s64, s64}
but we currently have no means to say that, for example, {s64, s32} is
not legal. Some operations such as G_INSERT/G_EXTRACT/G_MERGE_VALUES/
G_UNMERGE_VALUES has relationships between the types that are currently
described incorrectly.
Additionally, G_LOAD/G_STORE currently have no means to legalize non-atomics
differently to atomics. The necessary information is in the MMO but we have no
way to use this in the legalizer. Similarly, there is currently no way for the
register type and the memory type to differ so there is no way to cleanly
represent extending-load/truncating-store in a way that can't be broken by
optimizers (resulting in illegal MIR).
This patch introduces LegalityQuery which provides all the information
needed by the legalizer to make a decision on whether something is legal
and how to legalize it.
Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar, volkan, reames, bogner
Reviewed By: bogner
Subscribers: bogner, llvm-commits, kristof.beyls
Differential Revision: https://reviews.llvm.org/D42244
llvm-svn: 323342
r322086 removed the trailing information describing reg classes for each
register.
This patch adds printing reg classes next to every register when
individual operands/instructions/basic blocks are printed. In the case
of dumping MIR or printing a full function, by default don't print it.
Differential Revision: https://reviews.llvm.org/D42239
llvm-svn: 322867
Planning to add support for named vregs. This puts is in a conundrum since
physregs are named as well. To rectify this we need to use a sigil other than
'%' for physregs in MIR. We've settled on using '$' for physregs but first we
must repurpose it from external symbols using it, which is what this commit is
all about. We think '&' will have familiar semantics for C/C++ users.
llvm-svn: 322146
This test fails when run on the sanitizer bot, and I do not see a good
way to fix it. The existing bogus target in MachineInstrTest.cpp is only
good enough to create instructions but not sufficient to insert them into
basic blocks. The addNodeToList ilist callback dereferences the pointer
to the MachineRegisterInfo. Adding MachineRegisterInfo would also require
TargetRegisterInfo, even a minimal implementation of that would be quite
complicated. I would be glad to add this back if someone can suggest a
better way to do it.
llvm-svn: 321784
Add iterator ranges for machine instruction phis, similar to the IR-level
phi ranges added in r303964. I updated a few places to use this. Besides
general code simplification, this change will allow removing a non-upstream
change from Swift's copy of LLVM (in a better way than my previous attempt
in http://reviews.llvm.org/D19080).
https://reviews.llvm.org/D41672
llvm-svn: 321783
Work towards the unification of MIR and debug output by refactoring the
interfaces.
Also add support for printing with a null TargetIntrinsicInfo and no
MachineFunction.
llvm-svn: 321111
Work towards the unification of MIR and debug output by refactoring the
interfaces.
Before this patch we printed "<call frame instruction>" in the debug
output.
llvm-svn: 321084
Work towards the unification of MIR and debug output by printing
`<mcsymbol sym>` instead of `<MCSym=sym>`.
Only debug syntax is affected.
llvm-svn: 320685
Work towards the unification of MIR and debug output by printing
`liveout(...)` instead of `<regliveout>`.
Only debug syntax is affected.
llvm-svn: 320683
Work towards the unification of MIR and debug output by printing
`@foo` instead of `<ga:@foo>`.
Also print target flags in the MIR format since most of them are used on
global address operands.
Only debug syntax is affected.
llvm-svn: 320682
Work towards the unification of MIR and debug output by printing `target-index(target-specific) + 8` instead of `<ti#0+8>` and `target-index(target-specific) + 8` instead of `<ti#0-8>`.
Only debug syntax is affected.
llvm-svn: 320565
Work towards the unification of MIR and debug output by printing
`%const.0 + 8` instead of `<cp#0+8>` and `%const.0 - 8` instead of
`<cp#0-8>`.
Only debug syntax is affected.
Differential Revision: https://reviews.llvm.org/D41116
llvm-svn: 320564
Work towards the unification of MIR and debug output by refactoring the
interfaces.
Add support for operand subreg index as an immediate to debug printing
and use ::print in the MIRPrinter.
Differential Review: https://reviews.llvm.org/D40965
llvm-svn: 320209
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).
llvm-svn: 318490
This header includes CodeGen headers, and is not, itself, included by
any Target headers, so move it into CodeGen to match the layering of its
implementation.
llvm-svn: 317647
This changes the interface of how targets describe how to legalize, see
the below description.
1. Interface for targets to describe how to legalize.
In GlobalISel, the API in the LegalizerInfo class is the main interface
for targets to specify which types are legal for which operations, and
what to do to turn illegal type/operation combinations into legal ones.
For each operation the type sizes that can be legalized without having
to change the size of the type are specified with a call to setAction.
This isn't different to how GlobalISel worked before. For example, for a
target that supports 32 and 64 bit adds natively:
for (auto Ty : {s32, s64})
setAction({G_ADD, 0, s32}, Legal);
or for a target that needs a library call for a 32 bit division:
setAction({G_SDIV, s32}, Libcall);
The main conceptual change to the LegalizerInfo API, is in specifying
how to legalize the type sizes for which a change of size is needed. For
example, in the above example, how to specify how all types from i1 to
i8388607 (apart from s32 and s64 which are legal) need to be legalized
and expressed in terms of operations on the available legal sizes
(again, i32 and i64 in this case). Before, the implementation only
allowed specifying power-of-2-sized types (e.g. setAction({G_ADD, 0,
s128}, NarrowScalar). A worse limitation was that if you'd wanted to
specify how to legalize all the sized types as allowed by the LLVM-IR
LangRef, i1 to i8388607, you'd have to call setAction 8388607-3 times
and probably would need a lot of memory to store all of these
specifications.
Instead, the legalization actions that need to change the size of the
type are specified now using a "SizeChangeStrategy". For example:
setLegalizeScalarToDifferentSizeStrategy(
G_ADD, 0, widenToLargerAndNarrowToLargest);
This example indicates that for type sizes for which there is a larger
size that can be legalized towards, do it by Widening the size.
For example, G_ADD on s17 will be legalized by first doing WidenScalar
to make it s32, after which it's legal.
The "NarrowToLargest" indicates what to do if there is no larger size
that can be legalized towards. E.g. G_ADD on s92 will be legalized by
doing NarrowScalar to s64.
Another example, taken from the ARM backend is:
for (unsigned Op : {G_SDIV, G_UDIV}) {
setLegalizeScalarToDifferentSizeStrategy(Op, 0,
widenToLargerTypesUnsupportedOtherwise);
if (ST.hasDivideInARMMode())
setAction({Op, s32}, Legal);
else
setAction({Op, s32}, Libcall);
}
For this example, G_SDIV on s8, on a target without a divide
instruction, would be legalized by first doing action (WidenScalar,
s32), followed by (Libcall, s32).
The same principle is also followed for when the number of vector lanes
on vector data types need to be changed, e.g.:
setAction({G_ADD, LLT::vector(8, 8)}, LegalizerInfo::Legal);
setAction({G_ADD, LLT::vector(16, 8)}, LegalizerInfo::Legal);
setAction({G_ADD, LLT::vector(4, 16)}, LegalizerInfo::Legal);
setAction({G_ADD, LLT::vector(8, 16)}, LegalizerInfo::Legal);
setAction({G_ADD, LLT::vector(2, 32)}, LegalizerInfo::Legal);
setAction({G_ADD, LLT::vector(4, 32)}, LegalizerInfo::Legal);
setLegalizeVectorElementToDifferentSizeStrategy(
G_ADD, 0, widenToLargerTypesUnsupportedOtherwise);
As currently implemented here, vector types are legalized by first
making the vector element size legal, followed by then making the number
of lanes legal. The strategy to follow in the first step is set by a
call to setLegalizeVectorElementToDifferentSizeStrategy, see example
above. The strategy followed in the second step
"moreToWiderTypesAndLessToWidest" (see code for its definition),
indicating that vectors are widened to more elements so they map to
natively supported vector widths, or when there isn't a legal wider
vector, split the vector to map it to the widest vector supported.
Therefore, for the above specification, some example legalizations are:
* getAction({G_ADD, LLT::vector(3, 3)})
returns {WidenScalar, LLT::vector(3, 8)}
* getAction({G_ADD, LLT::vector(3, 8)})
then returns {MoreElements, LLT::vector(8, 8)}
* getAction({G_ADD, LLT::vector(20, 8)})
returns {FewerElements, LLT::vector(16, 8)}
2. Key implementation aspects.
How to legalize a specific (operation, type index, size) tuple is
represented by mapping intervals of integers representing a range of
size types to an action to take, e.g.:
setScalarAction({G_ADD, LLT:scalar(1)},
{{1, WidenScalar}, // bit sizes [ 1, 31[
{32, Legal}, // bit sizes [32, 33[
{33, WidenScalar}, // bit sizes [33, 64[
{64, Legal}, // bit sizes [64, 65[
{65, NarrowScalar} // bit sizes [65, +inf[
});
Please note that most of the code to do the actual lowering of
non-power-of-2 sized types is currently missing, this is just trying to
make it possible for targets to specify what is legal, and how non-legal
types should be legalized. Probably quite a bit of further work is
needed in the actual legalizing and the other passes in GlobalISel to
support non-power-of-2 sized types.
I hope the documentation in LegalizerInfo.h and the examples provided in the
various {Target}LegalizerInfo.cpp and LegalizerInfoTest.cpp explains well
enough how this is meant to be used.
This drops the need for LLT::{half,double}...Size().
Differential Revision: https://reviews.llvm.org/D30529
llvm-svn: 317560
This header already includes a CodeGen header and is implemented in
lib/CodeGen, so move the header there to match.
This fixes a link error with modular codegeneration builds - where a
header and its implementation are circularly dependent and so need to be
in the same library, not split between two like this.
llvm-svn: 317379
Reverting to investigate layering effects of MCJIT not linking
libCodeGen but using TargetMachine::getNameWithPrefix() breaking the
lldb bots.
This reverts commit r315633.
llvm-svn: 315637
Merge LLVMTargetMachine into TargetMachine.
- There is no in-tree target anymore that just implements TargetMachine
but not LLVMTargetMachine.
- It should still be possible to stub out all the various functions in
case a target does not want to use lib/CodeGen
- This simplifies the code and avoids methods ending up in the wrong
interface.
Differential Revision: https://reviews.llvm.org/D38489
llvm-svn: 315633
MachineInstr::isIdenticalTo has a lot of logic for dealing with register
Defs (i.e. deciding whether to take them into account or ignore them).
This logic gets things wrong in some obscure cases, for instance if an
operand is not a Def for both the current MI and the one we are
comparing to.
I'm not sure if it's possible for this to happen for regular register
operands, but it may happen in the ARM backend for special operands
which use sentinel values for the register (i.e. 0, which is neither a
physical register nor a virtual one).
This causes MachineInstrExpressionTrait::isEqual (which uses
MachineInstr::isIdenticalTo) to return true for the following
instructions, which are the same except for the fact that one sets the
flags and the other one doesn't:
%1114 = ADDrsi %1113, %216, 17, 14, _, def _
%1115 = ADDrsi %1113, %216, 17, 14, _, _
OTOH, MachineInstrExpressionTrait::getHashValue returns different values
for the 2 instructions due to the different isDef on the last operand.
In practice this means that when trying to add those instructions to a
DenseMap, they will be considered different because of their different
hash values, but when growing the map we might get an assertion while
copying from the old buckets to the new buckets because isEqual
misleadingly returns true.
This patch makes sure that isEqual and getHashValue agree, by improving
the checks in MachineInstr::isIdenticalTo when we are ignoring virtual
register definitions (which is what the Trait uses). Firstly, instead of
checking isPhysicalRegister, we use !isVirtualRegister, so that we cover
both physical registers and sentinel values. Secondly, instead of
checking MachineOperand::isReg, we use MachineOperand::isIdenticalTo,
which checks isReg, isSubReg and isDef, which are the same values that
the hash function uses to compute the hash.
Note that the function is symmetric with this change, since if the
current operand is not a Def, we check MachineOperand::isIdenticalTo,
which returns false if the operands have different isDef's.
Differential Revision: https://reviews.llvm.org/D38789
llvm-svn: 315579
With this change, the GlobalISel library gets always built. In
particular, this is not possible to opt GlobalISel out of the build
using the LLVM_BUILD_GLOBAL_ISEL variable any more.
llvm-svn: 309990
In r301116, a custom lowering needed to be introduced to be able to
legalize 8 and 16-bit divisions on ARM targets without a division
instruction, since 2-step legalization (WidenScalar from 8 bit to 32
bit, then Libcall the 32-bit division) doesn't work.
This fixes this and makes this kind of multi-step legalization, where
first the size of the type needs to be changed and then some action is
needed that doesn't require changing the size of the type,
straighforward to specify.
Differential Revision: https://reviews.llvm.org/D32529
llvm-svn: 306806
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.
Differential Revision: https://reviews.llvm.org/D33843
llvm-svn: 304864
clang-format (https://reviews.llvm.org/D33932) to keep primary headers
at the top and handle new utility headers like 'gmock' consistently with
other utility headers.
No other change was made. I did no manual edits, all of this is
clang-format.
This should allow other changes to have more clear and focused diffs,
and is especially motivated by moving some headers into more focused
libraries.
llvm-svn: 304786
Adds MVT::ElementCount to represent the length of a
vector which may be scalable, then adds helper functions
that work with it.
Patch by Graham Hunter.
Differential Revision: https://reviews.llvm.org/D32019
llvm-svn: 300842
This fixes PR32471.
As comment 10 on that bug report highlights
(https://bugs.llvm.org//show_bug.cgi?id=32471#c10), there are quite a
few different defendable design tradeoffs that could be made, including
not representing pointers at all in LLT.
I decided to go for representing vector-of-pointer as a concept in LLT,
while keeping the size of the LLT type 64 bits (this is an increase from
48 bits before). My rationale for keeping pointers explicit is that on
some targets probably it's very handy to have the distinction between
pointer and non-pointer (e.g. 68K has a different register bank for
pointers IIRC). If we keep a scalar pointer, it probably is easiest to
also have a vector-of-pointers to keep LLT relatively conceptually clean
and orthogonal, while we don't have a very strong reason to break that
orthogonality. Once we gain more experience on the use of LLT, we can
of course reconsider this direction.
Rejecting vector-of-pointer types in the IRTranslator is also an option
to avoid the crash reported in PR32471, but that is only a very
short-term solution; also needs quite a bit of code tweaks in places,
and is probably fragile. Therefore I didn't consider this the best
option.
llvm-svn: 300664
Vedant Kumar