Commit Graph

96 Commits

Author SHA1 Message Date
Wei Mi c022370767 Allow dead insts to be kept in DeadRemat only when they are rematerializable.
Because isReallyTriviallyReMaterializableGeneric puts many limits on
rematerializable instructions, this fix can prevent instructions with
tied virtual operands and instructions with virtual register uses from
being kept in DeadRemat, so as to workaround the live interval consistency
problem for the dummy instructions kept in DeadRemat.

But we still need to fix the live interval consistency problem. This patch
is just a short time relieve. PR28464 has been filed as a reminder.

Differential Revision: http://reviews.llvm.org/D19486

llvm-svn: 274928
2016-07-08 21:08:09 +00:00
Duncan P. N. Exon Smith 9cfc75c214 CodeGen: Use MachineInstr& in TargetInstrInfo, NFC
This is mostly a mechanical change to make TargetInstrInfo API take
MachineInstr& (instead of MachineInstr* or MachineBasicBlock::iterator)
when the argument is expected to be a valid MachineInstr.  This is a
general API improvement.

Although it would be possible to do this one function at a time, that
would demand a quadratic amount of churn since many of these functions
call each other.  Instead I've done everything as a block and just
updated what was necessary.

This is mostly mechanical fixes: adding and removing `*` and `&`
operators.  The only non-mechanical change is to split
ARMBaseInstrInfo::getOperandLatencyImpl out from
ARMBaseInstrInfo::getOperandLatency.  Previously, the latter took a
`MachineInstr*` which it updated to the instruction bundle leader; now,
the latter calls the former either with the same `MachineInstr&` or the
bundle leader.

As a side effect, this removes a bunch of MachineInstr* to
MachineBasicBlock::iterator implicit conversions, a necessary step
toward fixing PR26753.

Note: I updated WebAssembly, Lanai, and AVR (despite being
off-by-default) since it turned out to be easy.  I couldn't run tests
for AVR since llc doesn't link with it turned on.

llvm-svn: 274189
2016-06-30 00:01:54 +00:00
Quentin Colombet d307909a50 [LiveRangeEdit] Fix a crash in eliminateDeadDef.
When we delete a live-range, we check if that live-range is the origin of others
to keep it around for rematerialization. For that we check that the instruction
we are about to remove is the same as the definition of the VNI of the original
live-range.
If this is the case, we just shrink the live-range to an empty one.

Now, when we try to delete one of the children of such live-range (product of
splitting), we do the same check.
However, now the original live-range is empty and there is no way we can
access the VNI to check its definition, and we crash.

When we cannot get the VNI for the original live-range, that means we are not in
the presence of the original definition. Thus, this check does not need to happen
in that case and the crash is sloved!

This bug was introduced in r266162 | wmi | 2016-04-12 20:08:27. It affects every
target that uses the greedy register allocator.
To happen, we need to delete both a the original instruction and its split
products, in that order. This is likely to happen when rematerialization comes
into play.

Trying to produce a more robust test case. Will follow in a coming commit.

This fixes llvm.org/PR27983.

rdar://problem/26651519 

llvm-svn: 272314
2016-06-09 21:34:31 +00:00
Jonas Paulsson 8e5b0c65cc [foldMemoryOperand()] Pass LiveIntervals to enable liveness check.
SystemZ (and probably other targets as well) can fold a memory operand
by changing the opcode into a new instruction that as a side-effect
also clobbers the CC-reg.

In order to do this, liveness of that reg must first be checked. When
LIS is passed, getRegUnit() can be called on it and the right
LiveRange is computed on demand.

Reviewed by Matthias Braun.
http://reviews.llvm.org/D19861

llvm-svn: 269026
2016-05-10 08:09:37 +00:00
Wei Mi 963f2df4d2 Don't skip splitSeparateComponents in eliminateDeadDefs for HoistSpillHelper::hoistAllSpills.
Because HoistSpillHelper::hoistAllSpills is called in postOptimization, before the
patch we didn't want LiveRangeEdit::eliminateDeadDefs to call splitSeparateComponents
and generate unassigned new vregs. However, skipping splitSeparateComponents will make
verify-machineinstrs unhappy, so I remove the early return, and use
HoistSpillHelper::LRE_DidCloneVirtReg to assign physreg/stackslot for those new vregs.

In addition, some code reorganization to make class HoistSpillHelper privately inheriting
from LiveRangeEdit::Delegate possible. This is to be consistent with class RAGreedy and
class RegisterCoalescer.

Differential Revision: http://reviews.llvm.org/D19142

llvm-svn: 266489
2016-04-15 23:16:44 +00:00
Wei Mi 9a16d655c7 Recommit r265547, and r265610,r265639,r265657 on top of it, plus
two fixes with one about error verify-regalloc reported, and
another about live range update of phi after rematerialization.

r265547:
Replace analyzeSiblingValues with new algorithm to fix its compile
time issue. The patch is to solve PR17409 and its duplicates.

analyzeSiblingValues is a N x N complexity algorithm where N is
the number of siblings generated by reg splitting. Although it
causes siginificant compile time issue when N is large, it is also
important for performance since it removes redundent spills and
enables rematerialization.

To solve the compile time issue, the patch removes analyzeSiblingValues
and replaces it with lower cost alternatives containing two parts. The
first part creates a new spill hoisting method in postOptimization of
register allocation. It does spill hoisting at once after all the spills
are generated instead of inside every instance of selectOrSplit. The
second part queries the define expr of the original register for
rematerializaiton and keep it always available during register allocation
even if it is already dead. It deletes those dead instructions only in
postOptimization. With the two parts in the patch, it can remove
analyzeSiblingValues without sacrificing performance.

Patches on top of r265547:
r265610 "Fix the compare-clang diff error introduced by r265547."
r265639 "Fix the sanitizer bootstrap error in r265547."
r265657 "InlineSpiller.cpp: Escap \@ in r265547. [-Wdocumentation]"

Differential Revision: http://reviews.llvm.org/D15302
Differential Revision: http://reviews.llvm.org/D18934
Differential Revision: http://reviews.llvm.org/D18935
Differential Revision: http://reviews.llvm.org/D18936

llvm-svn: 266162
2016-04-13 03:08:27 +00:00
Hans Wennborg 5a7723c7a2 Revert r265547 "Recommit r265309 after fixed an invalid memory reference bug happened"
It caused PR27275: "ARM: Bad machine code: Using an undefined physical register"

Also reverting the following commits that were landed on top:
r265610 "Fix the compare-clang diff error introduced by r265547."
r265639 "Fix the sanitizer bootstrap error in r265547."
r265657 "InlineSpiller.cpp: Escap \@ in r265547. [-Wdocumentation]"

llvm-svn: 265790
2016-04-08 15:17:43 +00:00
Wei Mi 18293bef4e Recommit r265309 after fixed an invalid memory reference bug happened
when DenseMap growed and moved memory. I verified it fixed the bootstrap
problem on x86_64-linux-gnu but I cannot verify whether it fixes
the bootstrap error on clang-ppc64be-linux. I will watch the build-bot
result closely.

Replace analyzeSiblingValues with new algorithm to fix its compile
time issue. The patch is to solve PR17409 and its duplicates.

analyzeSiblingValues is a N x N complexity algorithm where N is
the number of siblings generated by reg splitting. Although it
causes siginificant compile time issue when N is large, it is also
important for performance since it removes redundent spills and
enables rematerialization.

To solve the compile time issue, the patch removes analyzeSiblingValues
and replaces it with lower cost alternatives containing two parts. The
first part creates a new spill hoisting method in postOptimization of
register allocation. It does spill hoisting at once after all the spills
are generated instead of inside every instance of selectOrSplit. The
second part queries the define expr of the original register for
rematerializaiton and keep it always available during register allocation
even if it is already dead. It deletes those dead instructions only in
postOptimization. With the two parts in the patch, it can remove
analyzeSiblingValues without sacrificing performance.

Differential Revision: http://reviews.llvm.org/D15302

llvm-svn: 265547
2016-04-06 15:41:07 +00:00
Wei Mi fb5252cac1 Revert r265309 and r265312 because they caused some errors I need to investigate.
llvm-svn: 265317
2016-04-04 17:45:03 +00:00
Wei Mi ffbc9c7f3b Replace analyzeSiblingValues with new algorithm to fix its compile
time issue. The patch is to solve PR17409 and its duplicates.

analyzeSiblingValues is a N x N complexity algorithm where N is
the number of siblings generated by reg splitting. Although it
causes siginificant compile time issue when N is large, it is also
important for performance since it removes redundent spills and
enables rematerialization.

To solve the compile time issue, the patch removes analyzeSiblingValues
and replaces it with lower cost alternatives containing two parts. The
first part creates a new spill hoisting method in postOptimization of
register allocation. It does spill hoisting at once after all the spills
are generated instead of inside every instance of selectOrSplit. The
second part queries the define expr of the original register for
rematerializaiton and keep it always available during register allocation
even if it is already dead. It deletes those dead instructions only in
postOptimization. With the two parts in the patch, it can remove
analyzeSiblingValues without sacrificing performance.

Differential Revision: http://reviews.llvm.org/D15302

llvm-svn: 265309
2016-04-04 16:42:40 +00:00
Duncan P. N. Exon Smith 3ac9cc6156 CodeGen: Take MachineInstr& in SlotIndexes and LiveIntervals, NFC
Take MachineInstr by reference instead of by pointer in SlotIndexes and
the SlotIndex wrappers in LiveIntervals.  The MachineInstrs here are
never null, so this cleans up the API a bit.  It also incidentally
removes a few implicit conversions from MachineInstrBundleIterator to
MachineInstr* (see PR26753).

At a couple of call sites it was convenient to convert to a range-based
for loop over MachineBasicBlock::instr_begin/instr_end, so I added
MachineBasicBlock::instrs.

llvm-svn: 262115
2016-02-27 06:40:41 +00:00
Matthias Braun e6a2485e1a TargetRegisterInfo: Add typedef unsigned LaneBitmask and use it where apropriate; NFC
llvm-svn: 248623
2015-09-25 21:51:14 +00:00
Matthias Braun d3dd1354a4 LiveIntervalAnalysis: Factor common code into splitSeparateComponents; NFC
llvm-svn: 248241
2015-09-22 03:44:41 +00:00
Robert Lougher 11a44b78a3 Trace copies when checking for rematerializability in spill weight calculation
PR24139 contains an analysis of poor register allocation. One of the findings
was that when calculating the spill weight, a rematerializable interval once
split is no longer rematerializable. This is because the isRematerializable
check in CalcSpillWeights.cpp does not follow the copies introduced by live
range splitting (after splitting, the live interval register definition is a
copy which is not rematerializable).

Reviewers: qcolombet

Differential Revision: http://reviews.llvm.org/D11686

llvm-svn: 244439
2015-08-10 11:59:44 +00:00
Matthias Braun c1e029e93d LiveRangeEdit: Fix liveranges not shrinking on subrange kill.
If a dead instruction we may not only have a last-use in the main live
range but also in a subregister range if subregisters are tracked. We
need to partially rebuild live ranges in both cases.

The testcase only broke when subregister liveness was enabled. I
commited it in the current form because there is currently no flag to
enable/disable subregister liveness.

This fixes PR23720.

llvm-svn: 238785
2015-06-01 21:26:26 +00:00
Matthias Braun 07066cca20 MachineInstr: Remove unused parameter.
llvm-svn: 237726
2015-05-19 21:22:20 +00:00
Eric Christopher 349d5886e5 MachineRegisterInfo can access TII off of the MachineFunction's
subtarget and so doesn't need the TargetMachine or to access via
getSubtargetImpl. Update all callers.

llvm-svn: 227160
2015-01-27 01:15:16 +00:00
Matthias Braun 311730ac78 LiveIntervalAnalysis: Factor out code to update liveness on vreg def removal
This cleans up code and is more in line with the general philosophy of
modifying LiveIntervals through LiveIntervalAnalysis instead of changing
them directly.

This also fixes a case where SplitEditor::removeBackCopies() would miss
the subregister ranges.

llvm-svn: 226690
2015-01-21 19:02:30 +00:00
Matthias Braun cfb8ad29b5 LiveIntervalAnalysis: Factor out code to update liveness on physreg def removal
This cleans up code and is more in line with the general philosophy of
modifying LiveIntervals through LiveIntervalAnalysis instead of changing
them directly.

llvm-svn: 226687
2015-01-21 18:50:21 +00:00
Matthias Braun 36768c684f LiveRangeEdit: Check for completely empy subranges after removing ValNos.
Completely empty subranges are not allowed and must be removed when
subreg liveness is enabled.

llvm-svn: 224804
2014-12-24 02:11:46 +00:00
Matthias Braun 09afa1ea74 LiveInterval: Use range based for loops for subregister ranges.
llvm-svn: 223991
2014-12-11 00:59:06 +00:00
Matthias Braun 96761959d4 LiveInterval: Use more range based for loops for value numbers and segments.
llvm-svn: 223978
2014-12-10 23:07:54 +00:00
Matthias Braun fe896c703c LiveRangeEdit: Adapt eliminateDeadDef() to subregister liveness.
llvm-svn: 223882
2014-12-10 01:12:23 +00:00
Craig Topper f98c606479 Add missing semicolon from r222118.
llvm-svn: 222119
2014-11-17 05:58:26 +00:00
Craig Topper cf0444ba2a Move register class name strings to a single array in MCRegisterInfo to reduce static table size and number of relocation entries.
Indices into the table are stored in each MCRegisterClass instead of a pointer. A new method, getRegClassName, is added to MCRegisterInfo and TargetRegisterInfo to lookup the string in the table.

llvm-svn: 222118
2014-11-17 05:50:14 +00:00
Jiangning Liu c3053129b9 Add TargetInstrInfo interface isAsCheapAsAMove.
llvm-svn: 214158
2014-07-29 01:55:19 +00:00
Chandler Carruth 1b9dde087e [Modules] Remove potential ODR violations by sinking the DEBUG_TYPE
define below all header includes in the lib/CodeGen/... tree. While the
current modules implementation doesn't check for this kind of ODR
violation yet, it is likely to grow support for it in the future. It
also removes one layer of macro pollution across all the included
headers.

Other sub-trees will follow.

llvm-svn: 206837
2014-04-22 02:02:50 +00:00
Craig Topper c0196b1b40 [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.
llvm-svn: 206142
2014-04-14 00:51:57 +00:00
Owen Anderson b36376efcb Switch a number of loops in lib/CodeGen over to range-based for-loops, now that
the MachineRegisterInfo iterators are compatible with it.

llvm-svn: 204075
2014-03-17 19:36:09 +00:00
Owen Anderson 16c6bf49b7 Phase 2 of the great MachineRegisterInfo cleanup. This time, we're changing
operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&.  At this point they almost behave like normal iterators!

Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.

llvm-svn: 203865
2014-03-13 23:12:04 +00:00
Arnaud A. de Grandmaison ea3ac1612c CalcSpillWeights: give a better describing name to calculateSpillWeights
Besides, this relates it more obviously to the VirtRegAuxInfo::calculateSpillWeightAndHint.

No functionnal change.

llvm-svn: 194404
2013-11-11 19:04:45 +00:00
Matthias Braun 34e1be9451 Represent RegUnit liveness with LiveRange instance
Previously LiveInterval has been used, but having a spill weight and
register number is unnecessary for a register unit.

llvm-svn: 192397
2013-10-10 21:29:02 +00:00
Matthias Braun 88dd0abd2d Pass LiveQueryResult by value
This makes the API a bit more natural to use and makes it easier to make
LiveRanges implementation details private.

llvm-svn: 192394
2013-10-10 21:28:52 +00:00
Andrew Trick 3bf33075ce Use LiveRangeQuery for instruction-level liveness queries.
Remove redundant or bug-prone LiveInterval APIs.

llvm-svn: 189685
2013-08-30 17:58:49 +00:00
Andrew Trick ff60477306 Replace LiveInterval::killedAt with isKilledAtInstr.
Return true for LRGs that end at EarlyClobber or Register slots.

llvm-svn: 189642
2013-08-30 04:31:01 +00:00
Mark Lacey 9d8103de7a Auto-compute live intervals on demand.
When new virtual registers are created during splitting/spilling, defer
creation of the live interval until we need to use the live interval.

Along with the recent commits to notify LiveRangeEdit when new virtual
registers are created, this makes it possible for functions like
TargetInstrInfo::loadRegFromStackSlot() and
TargetInstrInfo::storeRegToStackSlot() to create multiple virtual
registers as part of the process of generating loads/stores for
different register classes, and then have the live intervals for those
new registers computed when they are needed.

llvm-svn: 188437
2013-08-14 23:50:16 +00:00
Mark Lacey f367cd9239 Notify LiveRangeEdit of new virtual registers.
Add a delegate class to MachineRegisterInfo with a single virtual
function, MRI_NoteNewVirtualRegister(). Update LiveRangeEdit to inherit
from this delegate class and override the definition of the callback
with an implementation that tracks the newly created virtual registers.

llvm-svn: 188435
2013-08-14 23:50:09 +00:00
Mark Lacey f9ea88546f Track new virtual registers by register number.
Track new virtual registers by register number, rather than by the live
interval created for them. This is the first step in separating the
creation of new virtual registers and new live intervals.  Eventually
live intervals will be created and populated on demand after the virtual
registers have been created and used in instructions.

llvm-svn: 188434
2013-08-14 23:50:04 +00:00
Jakob Stoklund Olesen 4417c7b265 Remove unnecessary parameter to RenumberValues.
Patch by Matthias Braun!

llvm-svn: 188393
2013-08-14 17:28:52 +00:00
Andrew Trick cbd7305d09 Prevent LiveRangeEdit from deleting bundled instructions.
We have no targets on trunk that bundle before regalloc. However, we
have been advertising regalloc as bundle safe for use with out-of-tree
targets. We need to at least contain the parts of the code that are
still unsafe.

llvm-svn: 184620
2013-06-22 00:33:48 +00:00
Andrew Trick 6b9c49a275 Handle more cases in LiveRangeEdit::eliminateDeadDefs.
Live intervals for dead physregs may be created during coalescing. We
need to update these in the event that their instruction goes away.

crash.ll is the unit test that catches it when MI sched is enabled on
X86.

llvm-svn: 184572
2013-06-21 18:33:20 +00:00
Andrew Trick 530fc1f486 Refactor LiveRangeEdit::eliminateDeadDefs.
I want to add logic to handle more cases.

llvm-svn: 184571
2013-06-21 18:33:17 +00:00
Andrew Trick 7df3f01703 whitespace
llvm-svn: 184570
2013-06-21 18:33:14 +00:00
Benjamin Kramer e2a1d89e14 Switch spill weights from a basic loop depth estimation to BlockFrequencyInfo.
The main advantages here are way better heuristics, taking into account not
just loop depth but also __builtin_expect and other static heuristics and will
eventually learn how to use profile info. Most of the work in this patch is
pushing the MachineBlockFrequencyInfo analysis into the right places.

This is good for a 5% speedup on zlib's deflate (x86_64), there were some very
unfortunate spilling decisions in its hottest loop in longest_match(). Other
benchmarks I tried were mostly neutral.

This changes register allocation in subtle ways, update the tests for it.
2012-02-20-MachineCPBug.ll was deleted as it's very fragile and the instruction
it looked for was gone already (but the FileCheck pattern picked up unrelated
stuff).

llvm-svn: 184105
2013-06-17 19:00:36 +00:00
Jakub Staszak 26ac8a7b16 Add some constantness.
llvm-svn: 177356
2013-03-18 23:40:46 +00:00
Chandler Carruth ed0881b2a6 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

llvm-svn: 169131
2012-12-03 16:50:05 +00:00
Jakob Stoklund Olesen 26c9d70d28 Make the LiveRegMatrix analysis available to targets.
No functional change, just moved header files.

Targets can inject custom passes between register allocation and
rewriting. This makes it possible to tweak the register allocation
before rewriting, using the full global interference checking available
from LiveRegMatrix.

llvm-svn: 168806
2012-11-28 19:13:06 +00:00
Jakob Stoklund Olesen 4df59a9ff8 Avoid rematerializing a redef immediately after the old def.
PR14098 contains an example where we would rematerialize a MOV8ri
immediately after the original instruction:

  %vreg7:sub_8bit<def> = MOV8ri 9; GR32_ABCD:%vreg7
  %vreg22:sub_8bit<def> = MOV8ri 9; GR32_ABCD:%vreg7

Besides being pointless, it is also wrong since the original instruction
only redefines part of the register, and the value read by the new
instruction is wrong.

The problem was the LiveRangeEdit::allUsesAvailableAt() didn't
special-case OrigIdx == UseIdx and found the wrong SSA value.

llvm-svn: 166068
2012-10-16 22:51:58 +00:00
Jakob Stoklund Olesen cea596acf7 Remove LIS::isAllocatable() and isReserved() helpers.
All callers can simply use the corresponding MRI functions.

llvm-svn: 165985
2012-10-15 22:14:34 +00:00
Jakob Stoklund Olesen 1d19582a8f Avoid dereferencing a NULL pointer.
Fixes PR13943.

llvm-svn: 164778
2012-09-27 16:34:19 +00:00