Commit Graph

75 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
8d0963f72c Add EdgeBundles to SplitKit.
Edge bundles is an annotation on the CFG that turns it into a bipartite directed
graph where each basic block is connected to an outgoing and an ingoing bundle.
These bundles are useful for identifying regions of the CFG for live range
splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122301 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 01:50:21 +00:00
Jakob Stoklund Olesen
dfe3b6d2a9 Check that the register is live-in to the loop header before inserting copies in
the loop predecessors.

The register can be live-out from a predecessor without being live-in to the
loop header if there is a critical edge from the predecessor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122123 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-18 01:06:19 +00:00
Jakob Stoklund Olesen
6203295473 Fix build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121872 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 18:07:48 +00:00
Jakob Stoklund Olesen
697483addf Detect and enumerate bypass loops.
Bypass loops have the current live range live through, but contain no uses or
defs. Splitting around a bypass loop can free registers for other uses inside
the loop by spilling the split range.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121871 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 17:49:52 +00:00
Jakob Stoklund Olesen
521a453721 Separate SplitAnalysis::getSplitLoops().
This method returns the set of loops with uses that are candidates for
splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121870 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 17:41:19 +00:00
Jakob Stoklund Olesen
b5f327b30f No need to add liveness that's already there.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118742 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 23:56:00 +00:00
Jakob Stoklund Olesen
cfa7134a9c Basic rematerialization during splitting.
Whenever splitting wants to insert a copy, it checks if the value can be
rematerialized cheaply instead.

Missing features:
- Delete instructions when all uses have been rematerialized.
- Truncate live ranges to the remaining uses after rematerialization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118702 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 19:31:50 +00:00
Jakob Stoklund Olesen
376dcbd6c2 Tag debug output as regalloc
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118193 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-03 20:39:23 +00:00
Jakob Stoklund Olesen
3d4114c464 When inserting copies during splitting, always use the parent register as the
source, and let rewrite() clean it up.

This way, kill flags on the inserted copies are fixed as well during rewrite().

We can't just assume that all the copies we insert are going to be kills since
critical edges into loop headers sometimes require both source and dest to be
live out of a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117980 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 23:59:48 +00:00
Jakob Stoklund Olesen
79cb53ce95 Update kill flags while rewriting instructions after splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117959 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 21:51:29 +00:00
Jakob Stoklund Olesen
5b4bb218d1 Make sure copies are inserted after any exception handling labels at the top of
a basic block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117764 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-30 01:26:16 +00:00
Jakob Stoklund Olesen
3ccfce0e35 Don't transfer unused values to the new intervals formed by splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117673 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 17:47:49 +00:00
Benjamin Kramer
8a8e26fb18 Silence Release build warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117671 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 17:40:05 +00:00
Jakob Stoklund Olesen
c94fcb1507 Never propagate the idom value out of a block that defines its own value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117669 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 17:37:25 +00:00
Jakob Stoklund Olesen
e1dde7b05a Replace SplitKit SSA update with an iterative algorithm very similar to the one
in SSAUpdaterImpl.h

Verifying live intervals revealed that the old method was completely wrong, and
we need an iterative approach to calculating PHI placemant. Fortunately, we have
MachineDominators available, so we don't have to compute that over and over
like SSAUpdaterImpl.h must.

Live-out values are cached between calls to mapValue() and computed in a greedy
way, so most calls will be working with very small block sets.

Thanks to Bob for explaining how this should work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117599 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28 20:34:52 +00:00
Jakob Stoklund Olesen
d68f458244 Make MachineDominators available for SplitEditor. We are going to need it for
proper SSA updating.

This doesn't cause MachineDominators to be recomputed since we are already
requiring MachineLoopInfo which uses dominators as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117598 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28 20:34:50 +00:00
Jakob Stoklund Olesen
c95c1465fd Handle critical loop predecessors by making both inside and outside registers
live out.

This doesn't prevent us from inserting a loop preheader later on, if that is
better.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117424 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-27 00:39:07 +00:00
Jakob Stoklund Olesen
0960a650b7 Compute critical loop predecessors in the same way as critical loop exits.
Critical edges going into a loop are not as bad as critical exits. We can handle
them by splitting the critical edge, or by having both inside and outside
registers live out of the predecessor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117423 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-27 00:39:05 +00:00
Jakob Stoklund Olesen
3a0e0715a5 After splitting, compute connected components of all new registers, not just for
the remainder register.

Example:

bb0:
  x = 1
bb1:
  use(x)
  ...
  x = 2
  jump bb1

When x is isolated in bb1, the inner part breaks into two components, x1 and x2:

bb0:
  x0 = 1
bb1:
  x1 = x0
  use(x1)
  ...
  x2 = 2
  x0 = x2
  jump bb1

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117408 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:36:09 +00:00
Jakob Stoklund Olesen
f1354ae95a Call RenumberValues for all new registers created during splitting. This is
necessary to get correct hasPHIKill flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117406 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:36:05 +00:00
Jakob Stoklund Olesen
79c0262fa8 Preserve PHIDef bits in cloned values during splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117405 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:36:02 +00:00
Jakob Stoklund Olesen
2bfb324684 Be more strict about detecting multi-use blocks for isolation.
When a block has exactly two uses and the register is both live-in and live-out,
don't isolate the block. We would be inserting two copies, so we haven't really
made any progress.

If the live-in and live-out values separate into disconnected components after
splitting, we would be making progress. We can't detect that for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117169 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-22 22:48:56 +00:00
Jakob Stoklund Olesen
2c1442e1b2 Be more strict when detecting critical edges before loop splitting.
An exit block with a critical edge must only have predecessors in the loop, or
just before the loop. This guarantees that the inserted copies in the loop
predecessors dominate the exit block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117144 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-22 20:28:23 +00:00
Jakob Stoklund Olesen
532de3dc6e Add print methods
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117143 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-22 20:28:21 +00:00
Jakob Stoklund Olesen
9d999772df Don't include the destination interval in the union when computing
Parent - union(Y, ...). Doh.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117042 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-21 18:47:08 +00:00
Jakob Stoklund Olesen
9d5d48bc41 Eliminate curli from SplitEditor. Use the LiveRangeEdit reference instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116547 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-15 00:34:01 +00:00
Jakob Stoklund Olesen
2a0180fbff Move stack slot assignments into LiveRangeEdit.
All registers created during splitting or spilling are assigned to the same
stack slot as the parent register.

When splitting or rematting, we may not spill at all. In that case the stack
slot is still assigned, but it will be dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116546 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-15 00:16:55 +00:00
Jakob Stoklund Olesen
a17768f582 Create a new LiveRangeEdit class to keep track of the new registers created when
splitting or spillling, and to help with rematerialization.

Use LiveRangeEdit in InlineSpiller and SplitKit. This will eventually make it
possible to share remat code between InlineSpiller and SplitKit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116543 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-14 23:49:52 +00:00
Jakob Stoklund Olesen
ab00e9f498 Only split around a loop if the live range has uses outside the loop periphery.
Before we would also split around a loop if any peripheral block had multiple
uses. This could cause repeated splitting when splitting a different live range
would insert uses into the periphery.

Now -spiller=inline passes the nightly test suite again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116494 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-14 18:26:45 +00:00
Jakob Stoklund Olesen
7466927b1a Rename SplitEditor::rewrite to finish() and break it out into a couple of new
functions: computeRemainder and rewrite.

When the remainder breaks up into multiple components, remember to rewrite those
uses as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116121 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-08 23:42:21 +00:00
Jakob Stoklund Olesen
0253df9a89 After splitting, the remaining LiveInterval may be fragmented into multiple
connected components. These components should be allocated different virtual
registers because there is no reason for them to be allocated together.

Add the ConnectedVNInfoEqClasses class to calculate the connected components,
and move values to new LiveIntervals.

Use it from SplitKit::rewrite by creating new virtual registers for the
components.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116006 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 23:34:34 +00:00
Jakob Stoklund Olesen
452a9fdf54 Print more loop info.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115951 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 18:47:07 +00:00
Jakob Stoklund Olesen
8fc3d1187c Print out MBB number when rewriting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115950 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 18:47:05 +00:00
Jakob Stoklund Olesen
4b3041c43e Cache interval iterators in SplitEditor::addTruncSimpleRange so we only have to
do one find().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115929 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 17:56:39 +00:00
Jakob Stoklund Olesen
9b24afe41e Clean up debug printing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115928 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 17:56:35 +00:00
Jakob Stoklund Olesen
9b90d7eae2 Count uses in all nested loops, not just the deepest.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115710 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 23:10:12 +00:00
Jakob Stoklund Olesen
fc3ef3c2e9 Remove SplitAnalysis::removeUse. It was only used to make SplitAnalysis
reusable, but that is no longer relevant since a split will always replace the
original.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115709 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 23:10:09 +00:00
Jakob Stoklund Olesen
d00f7e0c76 dupli always has an interval now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115708 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 23:10:04 +00:00
Jakob Stoklund Olesen
2e2be60e03 We can split around loops with multiple exits now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115696 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 22:19:35 +00:00
Jakob Stoklund Olesen
57d0f2deb0 Update SplitEditor API to reflect the fact that the original live interval is
never kept after splitting.

Keeping the original interval made sense when the split region doesn't modify
the register, and the original is spilled. We can get the same effect by
detecting reloaded values when spilling around copies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115695 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 22:19:33 +00:00
Jakob Stoklund Olesen
dbc36091ff Intervals are half-open.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115694 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 22:19:29 +00:00
Jakob Stoklund Olesen
984a7fc32c When we find a reaching definition, make sure it is visited from all paths by
erasing it from the visited set. That ensures we create the right phi defs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115666 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 20:36:28 +00:00
Jakob Stoklund Olesen
fc60d7729b Don't use nextIndex to check for live out of instruction.
Insert copy after defining instruction.

Fix LiveIntervalMap::extendTo to properly handle live segments starting before
the current basic block.

Make sure the open live range is extended to the inserted copy's use slot.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115665 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-05 20:36:25 +00:00
Lang Hames
6e2968c85c Removed VNInfo::isDefAccurate(). Def "accuracy" can be checked by testing whether LiveIntervals::getInstructionFromIndex(def) returns NULL.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114791 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-25 12:04:16 +00:00
Jakob Stoklund Olesen
5fa42a45a1 Build the complement interval dupli after the split intervals instead of
creating it before and subtracting split ranges.

This way, the SSA update code in LiveIntervalMap can properly create and use new
phi values in dupli. Now it is possible to create split regions where a value
escapes along two different CFG edges, creating phi values outside the split
region.

This is a work in progress and probably quite broken.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114492 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-21 22:32:21 +00:00
Jakob Stoklund Olesen
f6a129a24b Use the value mapping provided by LiveIntervalMap. This simplifies the code a
great deal because we don't have to worry about maintaining SSA form.

Unconditionally copy back to dupli when the register is live out of the split
range, even if the live-out value was defined outside the range. Skipping the
back-copy only makes sense when the live range is going to spill outside the
split range, and we don't know that it will. Besides, this was a hack to avoid
SSA update issues.

Clear up some confusion about the end point of a half-open LiveRange. Methinks
LiveRanges need to be closed so both start and end are included in the range.
The low bits of a SlotIndex are symbolic, so a half-open range doesn't really
make sense. This would be a pervasive change, though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@114043 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-16 00:01:36 +00:00
Jakob Stoklund Olesen
dd9f3fdc77 Mechanically replace LiveInterval* with LiveIntervalMap for intervals being
edited without actually using LiveIntervalMap functionality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113816 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-13 23:29:11 +00:00
Jakob Stoklund Olesen
9ca2aeb2d2 Allow LiveIntervalMap to be reused by resetting the current live interval.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113815 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-13 23:29:09 +00:00
Jakob Stoklund Olesen
b3e9681cc0 Let's just declare that it is impossible to construct a std::pair from a null
pointer and work around that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113788 91177308-0d34-0410-b5e6-96231b3b80d8
2010-09-13 21:29:45 +00:00
Michael J. Spencer
6715be20e2 Fix the msvc 2010 build.
The Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.30319.01
implements parts of C++0x based on the draft standard. An old version of
the draft had a bug that makes std::pair<T1*, T2*>(something, 0) fail to
compile. This is because the template<class U, class V> pair(U&& x, V&& y)
constructor is selected, even though it later fails to implicitly convert
U and V to frist_type and second_type.

This has been fixed in n3090, but it seems that Microsoft is not going to
update msvc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111535 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-19 18:16:39 +00:00