Commit Graph

207 Commits

Author SHA1 Message Date
Matthias Braun
7d3ec5af28 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226690 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-21 19:02:30 +00:00
Matthias Braun
218d20a48b LiveInterval: Use more range based for loops for value numbers and segments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223978 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-10 23:07:54 +00:00
Eric Christopher
1dd55ba94e Grab the subtarget and subtarget dependent variables off of
MachineFunction rather than TargetMachine.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219671 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-14 07:22:00 +00:00
Eric Christopher
6035518e3b Have MachineFunction cache a pointer to the subtarget to make lookups
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214838 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-05 02:39:49 +00:00
Eric Christopher
9f85dccfc6 Remove the TargetMachine forwards for TargetSubtargetInfo based
information and update all callers. No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214781 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-04 21:25:23 +00:00
Chandler Carruth
8677f2ff9a [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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206837 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-22 02:02:50 +00:00
Craig Topper
4ba844388c [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206142 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-14 00:51:57 +00:00
Owen Anderson
92fca73d52 Switch a number of loops in lib/CodeGen over to range-based for-loops, now that
the MachineRegisterInfo iterators are compatible with it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204075 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-17 19:36:09 +00:00
Owen Anderson
bf63022492 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203865 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-13 23:12:04 +00:00
Benjamin Kramer
a4f0aad951 [C++11] Replace llvm::tie with std::tie.
The old implementation is no longer needed in C++11.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202644 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-02 13:30:33 +00:00
Benjamin Kramer
d628f19f5d [C++11] Replace llvm::next and llvm::prior with std::next and std::prev.
Remove the old functions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202636 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-02 12:27:27 +00:00
Matthias Braun
e25dde550b Work on LiveRange instead of LiveInterval where possible
Also change some pointer arguments to references at some places where
0-pointers are not allowed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192396 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-10 21:28:57 +00:00
Matthias Braun
331de11a0a Rename LiveRange to LiveInterval::Segment
The Segment struct contains a single interval; multiple instances of this struct
are used to construct a live range, but the struct is not a live range by
itself.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192392 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-10 21:28:43 +00:00
Mark Lacey
e742d68736 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188437 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-14 23:50:16 +00:00
Mark Lacey
1feb5854ae 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188434 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-14 23:50:04 +00:00
Jakob Stoklund Olesen
1c6d387dc9 Remove unnecessary parameter to RenumberValues.
Patch by Matthias Braun!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188393 91177308-0d34-0410-b5e6-96231b3b80d8
2013-08-14 17:28:52 +00:00
Benjamin Kramer
4eed756153 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).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184105 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-17 19:00:36 +00:00
Jakob Stoklund Olesen
1ead68d769 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168806 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-28 19:13:06 +00:00
Manman Ren
b720be6a50 Release build: guard dump functions with
"#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)"

No functional change. Update r163339.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163653 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-11 22:23:19 +00:00
Manman Ren
77e300e8f0 Release build: guard dump functions with "ifndef NDEBUG"
No functional change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163339 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 19:06:06 +00:00
Jakob Stoklund Olesen
1599a64277 Fix a couple of loops that were processing unused value numbers.
Unused VNInfos should be left alone. Their def SlotIndex doesn't point
to anything.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161257 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-03 20:59:29 +00:00
Jakob Stoklund Olesen
b18d779b35 Eliminate the IS_PHI_DEF flag and VNInfo::setIsPHIDef().
A value number is a PHI def if and only if it begins at a block
boundary. This can be derived from the def slot, a separate flag is not
necessary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160893 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-27 21:11:14 +00:00
Jakob Stoklund Olesen
631390e3c2 Pass context pointers to LiveRangeCalc::reset().
Remove the same pointers from all the other LiveRangeCalc functions,
simplifying the interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157941 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-04 18:21:16 +00:00
Pete Cooper
789d5d85ba Moved LiveRangeEdit.h so that it can be called from other parts of the backend, not just libCodeGen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153906 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-02 22:44:18 +00:00
Pete Cooper
8a06af9669 Refactored the LiveRangeEdit interface so that MachineFunction, TargetInstrInfo, MachineRegisterInfo, LiveIntervals, and VirtRegMap are all passed into the constructor and stored as members instead of passed in to each method.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153903 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-02 22:22:53 +00:00
Jakob Stoklund Olesen
3b1088a2cc Don't store COPY pointers in VNInfo.
If a value is defined by a COPY, that instuction can easily and cheaply
be found by getInstructionFromIndex(VNI->def).

This reduces the size of VNInfo from 24 to 16 bytes, and improves
llc compile time by 3%.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149763 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-04 05:20:49 +00:00
David Blaikie
4d6ccb5f68 More dead code removal (using -Wunreachable-code)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148578 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20 21:51:11 +00:00
Jakob Stoklund Olesen
2aad2f6e60 Detect when a value is undefined on an edge to a landing pad.
Consider this code:

int h() {
  int x;
  try {
    x = f();
    g();
  } catch (...) {
    return x+1;
  }
  return x;
}

The variable x is undefined on the first edge to the landing pad, but it
has the f() return value on the second edge to the landing pad.

SplitAnalysis::getLastSplitPoint() would assume that the return value
from f() was live into the landing pad when f() throws, which is of
course impossible.

Detect these cases, and treat them as if the landing pad wasn't there.
This allows spill code to be inserted after the function call to f().

<rdar://problem/10664933>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147912 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-11 02:07:05 +00:00
Jakob Stoklund Olesen
74c4f97a46 Exclusively use SplitAnalysis::getLastSplitPoint().
Delete the alternative implementation in LiveIntervalAnalysis.

These functions computed the same thing, but SplitAnalysis caches the
result.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147911 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-11 02:07:00 +00:00
Evan Cheng
5a96b3dad2 Add bundle aware API for querying instruction properties and switch the code
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.

For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146026 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07 07:15:52 +00:00
Jakob Stoklund Olesen
194eb71a11 Use getVNInfoBefore() when it makes sense.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144517 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-14 01:39:36 +00:00
Jakob Stoklund Olesen
1f81e316b0 Terminate all dead defs at the dead slot instead of the 'next' slot.
This makes no difference for normal defs, but early clobber dead defs
now look like:

  [Slot_EarlyClobber; Slot_Dead)

instead of:

  [Slot_EarlyClobber; Slot_Register).

Live ranges for normal dead defs look like:

  [Slot_Register; Slot_Dead)

as before.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144512 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-13 22:42:13 +00:00
Jakob Stoklund Olesen
2debd48ca7 Rename SlotIndexes to match how they are used.
The old naming scheme (load/use/def/store) can be traced back to an old
linear scan article, but the names don't match how slots are actually
used.

The load and store slots are not needed after the deferred spill code
insertion framework was deleted.

The use and def slots don't make any sense because we are using
half-open intervals as is customary in C code, but the names suggest
closed intervals.  In reality, these slots were used to distinguish
early-clobber defs from normal defs.

The new naming scheme also has 4 slots, but the names match how the
slots are really used.  This is a purely mechanical renaming, but some
of the code makes a lot more sense now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144503 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-13 20:45:27 +00:00
Jakob Stoklund Olesen
ebac0c1747 Spill mode: Hoist back-copies locally.
The leaveIntvAfter() function normally inserts a back-copy after the
requested instruction, making the back-copy kill the live range.

In spill mode, try to insert the back-copy before the last use instead.
That means the last use becomes the kill instead of the back-copy.  This
lowers the register pressure because the last use can now redefine the
same register it was reading.

This will also improve compile time: The back-copy isn't a kill, so
hoisting it in hoistCopiesForSize() won't force a recomputation of the
source live range.  Similarly, if the back-copy isn't hoisted by the
splitter, the spiller will not attempt hoisting it locally.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139883 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-16 00:03:35 +00:00
Jakob Stoklund Olesen
c4c633852f Hoist back-copies to the least busy dominator.
When a back-copy is hoisted to the nearest common dominator, keep
looking up the dominator tree for a less loopy dominator, and place the
back-copy there instead.

Don't do this when a single existing back-copy dominates all the others.
Assume the client knows what he is doing, and keep the dominating
back-copy.

This prevents us from hoisting back-copies into loops in most cases.  If
a value is defined in a loop with multiple exits, we may still hoist
back-copies into that loop.  That is the speed/size tradeoff.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139698 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-14 16:45:39 +00:00
Jakob Stoklund Olesen
393bfcb263 Distinguish complex mapped values from forced recomputation.
When a ParentVNI maps to multiple defs in a new interval, its live range
may still be derived directly from RegAssign by transferValues().

On the other hand, when instructions have been rematerialized or
hoisted, it may be necessary to completely recompute live ranges using
LiveRangeCalc::extend() to all uses.

Use a bit in the value map to indicate that a live range must be
recomputed.  Rename markComplexMapped() to forceRecompute().

This fixes some live range verification errors when
-split-spill-mode=size hoists back-copies by recomputing source ranges
when RegAssign kills can't be moved.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139660 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 23:09:04 +00:00
Jakob Stoklund Olesen
b21abfed81 Implement -split-spill-mode=size.
Whenever the complement interval is defined by multiple copies of the
same value, hoist those back-copies to the nearest common dominator.

This ensures that at most one copy is inserted per value in the
complement inteval, and no phi-defs are needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139651 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 22:22:39 +00:00
Jakob Stoklund Olesen
e5a2e36632 Add SplitEditor::markOverlappedComplement().
This function is used to flag values where the complement interval may
overlap other intervals.  Call it from overlapIntv, and use the flag to
fully recompute those live ranges in transferValues().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139612 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 18:05:29 +00:00
Jakob Stoklund Olesen
abcc73e8ba Eliminate the extendRange() wrapper.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139608 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 17:38:57 +00:00
Jakob Stoklund Olesen
ee5655dca4 Switch extendInBlock() to take a kill slot instead of the last use slot.
Three out of four clients prefer this interface which is consistent with
extendIntervalEndTo() and LiveRangeCalc::extend().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139604 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 16:47:56 +00:00
Jakob Stoklund Olesen
c1c622ef0d Use a separate LiveRangeCalc for the complement in spill modes.
The complement interval may overlap the other intervals created, so use
a separate LiveRangeCalc instance to compute its live range.

A LiveRangeCalc instance can only be shared among non-overlapping
intervals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139603 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 16:47:53 +00:00
Jakob Stoklund Olesen
b5a457c4cb Extract live range calculations from SplitKit.
SplitKit will soon need two copies of these data structures, and the
algorithms will also be useful when LiveIntervalAnalysis becomes
independent of LiveVariables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139572 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13 01:34:21 +00:00
Jakob Stoklund Olesen
708d06f7fb Add an interface for SplitKit complement spill modes.
SplitKit always computes a complement live range to cover the places
where the original live range was live, but no explicit region has been
allocated.

Currently, the complement live range is created to be as small as
possible - it never overlaps any of the regions.  This minimizes
register pressure, but if the complement is going to be spilled anyway,
that is not very important.  The spiller will eliminate redundant
spills, and hoist others by making the spill slot live range overlap
some of the regions created by splitting.  Stack slots are cheap.

This patch adds the interface to enable spill modes in SplitKit.  In
spill mode, SplitKit will assume that the complement is going to spill,
so it will allow it to overlap regions in order to avoid back-copies.
By doing some of the spiller's work early, the complement live range
becomes simpler.  In some cases, it can become much simpler because no
extra PHI-defs are required.  This will speed up both splitting and
spilling.

This is only the interface to enable spill modes, no implementation yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139500 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-12 16:49:21 +00:00
Jakob Stoklund Olesen
75e28f74b0 Delete getMultiUseBlocks and splitSingleBlocks.
These functions are no longer used, and they are easily replaced with a
loop calling shouldSplitSingleBlock and splitSingleBlock.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136993 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 22:52:17 +00:00
Jakob Stoklund Olesen
2d6d86be84 Split around single instructions to enable register class inflation.
Normally, we don't create a live range for a single instruction in a
basic block, the spiller does that anyway. However, when splitting a
live range that belongs to a proper register sub-class, inserting these
extra COPY instructions completely remove the constraints from the
remainder interval, and it may be allocated from the larger super-class.

The spiller will mop up these small live ranges if we end up spilling
anyway. It calls them snippets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136989 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 22:20:45 +00:00
Jakob Stoklund Olesen
fe62d92b7b Rename {First,Last}Use to {First,Last}Instr.
With a 'FirstDef' field right there, it is very confusing that FirstUse
refers to an instruction that may be a def.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136739 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 22:54:14 +00:00
Jakob Stoklund Olesen
77ee1140a3 Add a BlockInfo::FirstDef field.
This is either an invalid SlotIndex, or valno->def for the first value
defined inside the block. PHI values are not counted as defined inside
the block.

The FirstDef field will be used when estimating the cost of spilling
around a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136736 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 22:37:22 +00:00
Jakob Stoklund Olesen
4751eb760e Delete BlockInfo::LiveThrough. It wasn't used any more.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136735 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 22:37:20 +00:00
Jakob Stoklund Olesen
81d686edbe Never extend live ranges for <undef> uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135886 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-24 20:33:23 +00:00
Jakob Stoklund Olesen
b09701db9e Correctly handle <undef> tied uses when rewriting after a split.
This fixes PR10463. A two-address instruction with an <undef> use
operand was incorrectly rewritten so the def and use no longer used the
same register, violating the tie constraint.

Fix this by always rewriting <undef> operands with the register a def
operand would use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135885 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-24 20:23:50 +00:00