During register allocation, some instructions can have stack spills fused
into them. It means that when vregs are allocated on the stack we can
convert:
SETCCr %0
DBG_VALUE %0
to
SETCCm %stack.0
DBG_VALUE %stack.0
Unfortunately instruction referencing finds this harder: a store to the
stack doesn't have a specific operand number, therefore we don't substitute
the old operand for a new operand, and the location is dropped. This patch
implements a solution: just recognise the memory operand attached to an
instruction with a Special Number (TM), and record a substitution between
the old value and the new one.
This patch adds substitution code to InlineSpiller to record such fused
spills, and tracking in InstrRefBasedLDV to recognise such values, and
produce the value numbers for them. Everything to do with the movement of
stack-defined values is already handled in InstrRefBasedLDV.
Differential Revision: https://reviews.llvm.org/D111317
statepoint instruction uses tied-def registers to represent live gc value which
is use and def at the same time on a call.
At the same time invoke statepoint instruction is a last split point which can throw and
jump to landing pad.
As a result we have instructon which is last split point with tied-defs registers and
we need to teach Greedy RA to work with it.
The option -use-registers-for-gc-values-in-landing-pad controls whether statepoint lowering
will generate tied-defs for invoke statepoint and is off by default now.
To resolve all issues the following changes has been done.
1) Last Split point for invoke statepoint should be statepoint itself
If statepoint has a def it is a relocated gc pointer and it should be available in landing pad.
So we cannot split interval after statepoint at end of basic block.
2) Do not split interval on tied-def
If end of interval for overlap utility is a use which has tied-def we
should not split interval on this instruction due to in this case use
and def may have different registers and it breaks tied-def property.
3) Take into account Last Split Point for enterIntvAtEnd
If the use after Last Split Point is a def so it should be tied-def and
we can take the def of the tied-use as ParentVNI and thus
tied-use and tied-def will be live in resulting interval.
4) Handle the case when def is after LIP in InlineSpiller
If def of LI is after last insertion point of basic block we cannot hoist in this BB.
The example of such instruction is invoke statepoint where def represents the
relocated live gc pointer. Invoke is a last insertion point and its def is located after it.
In this case there is no place to insert spill and we bail out.
5) Fix removeBackCopies to account empty copies
RegAssignMap cannot hold empty interval, so do not set stop
to kill value if it produces empty interval.
This can happen if we remove back-copy and right before that we have another
back-copy.
For example, for parent %0 we can get
%1 = COPY %0
%2 = COPY %0
while we removing %2 we cannot set kill for %1 due to its empty.
6) Do not hoist copy to BB if its def is after LSP
If the parent def is a LastSplitPoint or later we cannot hoist copy to this basic block
because inserted copy (or re-materialization) will be located before the def.
All parts have been reviewed separately as follows:
https://reviews.llvm.org/D100747https://reviews.llvm.org/D100748https://reviews.llvm.org/D100750https://reviews.llvm.org/D100927https://reviews.llvm.org/D100945https://reviews.llvm.org/D101028
Reviewers: reames, rnk, void, MatzeB, wmi, qcolombet
Reviewed By: reames, qcolombet
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D101150
This is mostly NFC except that for end of BB not previous slot is used.
Idx is used to find a def of sibling live interval in that slot.
The def on end of MBB and on previous slot of end MBB should be the same,
so it should be NFC.
Reviewers: reames, qcolombet, MatzeB, wmi, rnk
Reviewed By: rnk
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D100922
This patch adds handling for DBG_VALUE_LIST in the MIR-passes (after
finalize-isel), excluding the debug liveness passes and DWARF emission. This
most significantly affects MachineSink, which now needs to consider all used
registers of a debug value when sinking, but for most passes this change is
simply replacing getDebugOperand(0) with an iteration over all debug operands.
Differential Revision: https://reviews.llvm.org/D92578
This patch adds a new instruction that can represent variadic debug values,
DBG_VALUE_VAR. This patch alone covers the addition of the instruction and a set
of basic code changes in MachineInstr and a few adjacent areas, but does not
correctly handle variadic debug values outside of these areas, nor does it
generate them at any point.
The new instruction is similar to the existing DBG_VALUE instruction, with the
following differences: the operands are in a different order, any number of
values may be used in the instruction following the Variable and Expression
operands (these are referred to in code as “debug operands”) and are indexed
from 0 so that getDebugOperand(X) == getOperand(X+2), and the Expression in a
DBG_VALUE_VAR must use the DW_OP_LLVM_arg operator to pass arguments into the
expression.
The new DW_OP_LLVM_arg operator is only valid in expressions appearing in a
DBG_VALUE_VAR; it takes a single argument and pushes the debug operand at the
index given by the argument onto the Expression stack. For example the
sub-expression `DW_OP_LLVM_arg, 0` has the meaning “Push the debug operand at
index 0 onto the expression stack.”
Differential Revision: https://reviews.llvm.org/D82363
VirtRegAuxInfo is an extensibility point, so the register allocator's
decision on which implementation to use should be communicated to the
other users - namely, LiveRangeEdit.
Differential Revision: https://reviews.llvm.org/D96898
This is a additional bug fix for c5be0e0cc0. The distance for
the spill instructions is wrong in previous patch.
Differential Revision: https://reviews.llvm.org/D94772
InlineSpiller::foldMemoryOperand unties registers before an attempt to fold and
does not restore tied-ness in case of failure.
I do not have a particular test for demo of invalid behavior.
This is something of clean-up.
It is better to keep the behavior correct in case some time in future it happens.
Reviewers: reames, dantrushin
Reviewed By: dantrushin, reames
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D94389
Change [x86] Fix tile register spill issue was causing problems for our build
using gcc-5.4.1
The problem was caused by this line:
for (const MachineInstr &MI : make_range(MIS.begin(), MI))
where MI was previously defined as a MachineBasicBlock iterator.
Differential Revision: https://reviews.llvm.org/D94415
The tile register spill need 2 instructions.
%46:gr64_nosp = MOV64ri 64
TILESTORED %stack.2, 1, killed %46:gr64_nosp, 0, $noreg, %43:tile
The first instruction load the stride to a GPR, and the second
instruction store tile register to stack slot. The optimization of merge
spill instruction is done after register allocation. And spill tile
register need create a new virtual register to for stride, so we can't
hoist tile spill instruction in postOptimization() of register
allocation. We can't hoist TILESTORED alone and we can't hoist the 2
instuctions together because MOV64ri will clobber some GPR. This patch
is to disble the spill merge for any spill which need 2 instructions.
Differential Revision: https://reviews.llvm.org/D93898
This patch implements amx programming model that discussed in llvm-dev
(http://lists.llvm.org/pipermail/llvm-dev/2020-August/144302.html).
Thank Hal for the good suggestion in the RA. The fast RA is not in the patch yet.
This patch implemeted 7 components.
1. The c interface to end user.
2. The AMX intrinsics in LLVM IR.
3. Transform load/store <256 x i32> to AMX intrinsics or split the
type into two <128 x i32>.
4. The Lowering from AMX intrinsics to AMX pseudo instruction.
5. Insert psuedo ldtilecfg and build the def-use between ldtilecfg to amx
intruction.
6. The register allocation for tile register.
7. Morph AMX pseudo instruction to AMX real instruction.
Change-Id: I935e1080916ffcb72af54c2c83faa8b2e97d5cb0
Differential Revision: https://reviews.llvm.org/D87981
Also renamed the fields to follow style guidelines.
Accessors help with readability - weight mutation, in particular,
is easier to follow this way.
Differential Revision: https://reviews.llvm.org/D87725
Implement proper folding of statepoint meta operands (deopt and GC)
when statepoint uses tied registers.
For deopt operands it is just about properly preserving tiedness
in new instruction.
For tied GC operands folding is a little bit more tricky.
We can fold tied GC operands only from InlineSpiller, because it knows
how to properly reload tied def after it was turned into memory operand.
Other users (e.g. peephole) cannot properly fold such operands as they
do not know how (or when) to reload them from memory.
We do this by un-tieing operand we want to fold in InlineSpiller
and allowing to fold only untied operands in foldPatchpoint.
Summary:
Avoid exposing details about how children are stored. This will enable
subsequent type-erasure changes.
New methods are introduced to cover common access patterns.
Change-Id: Idb5f4b1b9c84e4cc71ddb39bb52a388682f5674f
Reviewers: arsenm, RKSimon, mehdi_amini, courbet
Subscribers: qcolombet, sdardis, wdng, hiraditya, jrtc27, zzheng, atanasyan, asbirlea, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D83083
It's pretty silly to diagnose on a scalar copy but the build does that:
loop variable 'SibReg' of type 'const llvm::Register' creates a copy from type 'const llvm::Register' [-Wrange-loop-analysis]
Summary:
This invariant is being violated in the test case
https://reviews.llvm.org/D77849, related to the use of the relatively
new ability for callbr to have return values, and MachineBasicBlocks
with INLINEASM_BR terminators to emit live out register defs.
As noted in the comment, this triggers invariant violations in
MachineVerifier via `llc -verify-machineinstrs` or
`llc -verify-regalloc`, since only MachineInstrs that are terminators
are allowed to follow the first terminator.
https://reviews.llvm.org/D75098 may rework this very assertion if we're
spilling via a (proposed) TCOPY MachineInstr.
Reviewers: void, efriedma, arsenm
Reviewed By: efriedma
Subscribers: qcolombet, wdng, hiraditya, llvm-commits, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78166
Summary:
The repeated use of std::next() on a MachineBasicBlock::iterator was
clever, but we only need to reconstruct the iterator post creation of
the spill instruction.
This helps simplifying where we plan to place the spill, as discussed in
D77849.
From here, we can simplify the code a little by flipping the return code
of a helper.
Reviewers: efriedma
Reviewed By: efriedma
Subscribers: qcolombet, hiraditya, llvm-commits, srhines
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D78520
Summary:
Refactor LiveRangeCalc such that it is now split into two classes
The objective is to split all the "register specific" logic away
from LiveRangeCalc.
The two new classes created are:
- LiveRangeCalc - is meant as a generic class to compute and modify
live ranges in a generic way. This class should deal only with
SlotIndices and VNInfo objects.
- LiveIntervalCals - is meant to be equivalent to the old LiveRangeCalc.
It computes the liveness virtual registers tracked by a LiveInterval
object.
With this refactoring LiveRangeCalc can be used to implement tracking of
liveness of LiveRanges that represent other things than just registers.
Subscribers: MatzeB, qcolombet, mgorny, hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D76584
This allows Spiller.h to be used and included outside of
the lib/CodeGen directory. For example to be used in the
lib/Target directory or other places.
We should be careful to allow count of re-materialization of operands to be less
then number of physical registers.
STATEPOINT instruction has a variable number of operands and potentially very big.
So re-materialization for all operands is disabled at the moment if restrict-statepoint-remat is true.
The patch relaxes the re-materialization restriction for STATEPOINT instruction allowing it for
fixed operands. Specifically it is about call target.
Reviewers: reames
Reviewed By: reames
Subscribers: llvm-commits, qcolombet, hiraditya
Differential Revision: https://reviews.llvm.org/D75335
Use the isCandidateForCallSiteEntry().
This should mostly be an NFC, but there are some parts ensuring
the moveCallSiteInfo() and copyCallSiteInfo() operate with call site
entry candidates (both Src and Dest should be the call site entry
candidates).
Differential Revision: https://reviews.llvm.org/D74122
analyzePhysReg does not really fit into the iterator and moving it
makes it easier to change the base iterator.
Reviewers: evandro, t.p.northover, paquette, MatzeB, arsenm, qcolombet
Reviewed By: arsenm
Differential Revision: https://reviews.llvm.org/D70559
analyzeVirtReg does not really fit into the iterator and moving it
makes it easier to change the base iterator.
Reviewers: evandro, t.p.northover, paquette, MatzeB, arsenm, qcolombet
Reviewed By: qcolombet
Differential Revision: https://reviews.llvm.org/D70558
During the If-Converter optimization pay attention when copying or
deleting call instructions in order to keep call site information in
valid state.
Reviewers: aprantl, vsk, efriedma
Reviewed By: vsk, efriedma
Differential Revision: https://reviews.llvm.org/D66955
llvm-svn: 374068
Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).
Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor
Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&
Depends on D65919
Reviewers: arsenm, bogner, craig.topper, RKSimon
Reviewed By: arsenm
Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D65962
llvm-svn: 369041
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
Handle call instruction replacements and deletions in order to preserve
valid state of the call site info of the MachineFunction.
NOTE: If the call site info is enabled for a new target, the assertion from
the MachineFunction::DeleteMachineInstr() should help to locate places
where the updateCallSiteInfo() should be called in order to preserve valid
state of the call site info.
([10/13] Introduce the debug entry values.)
Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>
Differential Revision: https://reviews.llvm.org/D61062
llvm-svn: 364536
This patch aims to reduce spilling and register moves by using the 3-address
versions of instructions per default instead of the 2-address equivalent
ones. It seems that both spilling and register moves are improved noticeably
generally.
Regalloc hints are passed to increase conversions to 2-address instructions
which are done in SystemZShortenInst.cpp (after regalloc).
Since the SystemZ reg/mem instructions are 2-address (dst and lhs regs are
the same), foldMemoryOperandImpl() can no longer trivially fold a spilled
source register since the reg/reg instruction is now 3-address. In order to
remedy this, new 3-address pseudo memory instructions are used to perform the
folding only when the dst and lhs virtual registers are known to be allocated
to the same physreg. In order to not let MachineCopyPropagation run and
change registers on these transformed instructions (making it 3-address), a
new target pass called SystemZPostRewrite.cpp is run just after
VirtRegRewriter, that immediately lowers the pseudo to a target instruction.
If it would have been possibe to insert a COPY instruction and change a
register operand (convert to 2-address) in foldMemoryOperandImpl() while
trusting that the caller (e.g. InlineSpiller) would update/repair the
involved LiveIntervals, the solution involving pseudo instructions would not
have been needed. This is perhaps a potential improvement (see Phabricator
post).
Common code changes:
* A new hook TargetPassConfig::addPostRewrite() is utilized to be able to run a
target pass immediately before MachineCopyPropagation.
* VirtRegMap is passed as an argument to foldMemoryOperand().
Review: Ulrich Weigand, Quentin Colombet
https://reviews.llvm.org/D60888
llvm-svn: 362868
This is a recommit of r335091 Add more test cases for deopt-operands via regalloc, and r335077 [InlineSpiller] Fix a crash due to lack of forward progress from remat specifically for STATEPOINT. They were reverted due to a crash.
This change includes the text of both original changes, but also includes three aditional pieces:
1) A bug fix for the observed crash. I had failed to record the failed remat value as live which resulted in an instruction being deleted which still had uses. With the machine verifier, this is caught quickly. Without it, we fail in StackSlotColoring due to an empty live interval from LiveStack.
2) A test case which demonstrates the fix for (1). See @test11.
3) A control flag which defaults to disabling this for the moment. Once I've run more extensive validaton, I will switch the default and then remove this flag.
llvm-svn: 353871
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
This patch covers up a fairly fundemental issue around remat and register allocation which shows up with psuedo instructions with more vreg uses than there are physical registers. This patch essentially just disables remat for STATEPOINTs which are the only case we've seen so far, but long term we need a better fix.
For STATEPOINTs specifically, this is a strict improvement. It unblocks progress towards enabling a currently off-by-default mode which integrates deopt bundle operand lowering with register allocator spilling so that we end up with smaller stack sizes and more optimally placed spills. Assming no other issues turn up during my next round of integration testing - which based on experience so far, is admittedly unlikely - we might finally be able to enable something I've been working towards in small bits and pieces for years now. :)
For psuedo ops in general, there are a couple of ideas for a "proper fix" discussed on the bug, but I'm far enough outside my knowledge area to not be able to see any of them through to a successful conclusion. If anyone wants to help out here, please do.
Differential Revision: https://reviews.llvm.org/D41098
llvm-svn: 335077
The instructions using registers should be DBG_VALUE and normal
instructions. Use isDebugValue() to filter out DBG_VALUE and add
an assert to ensure there is no other kind of debug instructions
using the registers.
Differential Revision: https://reviews.llvm.org/D46739
Patch by Hsiangkai Wang.
llvm-svn: 332427
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.
In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.
Differential Revision: https://reviews.llvm.org/D43624
llvm-svn: 332240
serge-sans-paille