Commit Graph

77 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
7941350101 Fix PR10387.
When trying to rematerialize a value before an instruction that has an
early-clobber redefine of the virtual register, make sure to look up the
correct value number.

Early-clobber defs are moved one slot back, so getBaseIndex is needed to
find the used value number.

Bugpoint was unable to reduce the test case for this, see PR10388.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135378 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 05:31:59 +00:00
Jakob Stoklund Olesen
4f4a6fcd16 Oops, didn't mean to commit that.
Spills should be hoisted out of loops, but we don't want to hoist them
to dominating blocks at the same loop depth. That could cause the spills
to be executed more often.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134782 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-09 01:02:44 +00:00
Jakob Stoklund Olesen
56573cc1ae Hoist spills within a basic block.
Try to move spills as early as possible in their basic block. This can
help eliminate interferences by shortening the live range being
spilled.

This fixes PR10221.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134776 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-09 00:25:03 +00:00
Jakob Stoklund Olesen
9693d4c3f0 Fix PR10277.
Remat during spilling triggers dead code elimination. If a phi-def
becomes unused, that may also cause live ranges to split into separate
connected components.

This type of splitting is different from normal live range splitting. In
particular, there may not be a common original interval.

When the split range is its own original, make sure that the new
siblings are also their own originals. The range being split cannot be
used as an original since it doesn't cover the new siblings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134413 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-05 15:38:41 +00:00
Rafael Espindola
cfe5254cd3 Create a isFullCopy predicate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134189 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-30 21:15:52 +00:00
Jakob Stoklund Olesen
443443cc83 Avoid hoisting spills when looking at a copy from another register that is also
about to be spilled.

This can only happen when two extra snippet registers are included in the spill,
and there is a copy between them. Hoisting the spill creates problems because
the hoist will mark the copy for later dead code elimination, and spilling the
second register will turn the copy into a spill.

<rdar://problem/9420853>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131192 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-11 18:25:10 +00:00
Jakob Stoklund Olesen
e9bd4ea5fd Add some statistics to the splitting and spilling frameworks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130931 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-05 17:22:53 +00:00
Jakob Stoklund Olesen
6ee56e658a Avoid using stale entries form the sibling value map.
This could happen when trying to use a value that had been eliminated after dead
code elimination and folding loads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130597 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-30 06:42:21 +00:00
Jakob Stoklund Olesen
3b7d917dec Add debug output for rematerializable instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129883 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-20 22:14:20 +00:00
Jakob Stoklund Olesen
5d5ef4a886 Handle spilling around an instruction that has an early-clobber re-definition of
the spilled register.

This is quite common on ARM now that some stores have early-clobber defines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129714 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-18 20:23:27 +00:00
Jakob Stoklund Olesen
312babc93f Pick a conservative register class when creating a small live range for remat.
The rematerialized instruction may require a more constrained register class
than the register being spilled. In the test case, the spilled register has been
inflated to the DPR register class, but we are rematerializing a load of the
ssub_0 sub-register which only exists for DPR_VFP2 registers.

The register class is reinflated after spilling, so the conservative choice is
only temporary.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128610 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-31 03:54:44 +00:00
Jakob Stoklund Olesen
6094bd87d8 Recompute register class and hint for registers created during spilling.
The spill weight is not recomputed for an unspillable register - it stays infinite.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128490 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 21:20:19 +00:00
Jakob Stoklund Olesen
cf610d07de Remember to use the correct register when rematerializing for snippets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128469 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 17:47:02 +00:00
Jakob Stoklund Olesen
c1d22d8adb Run dead code elimination immediately after rematerialization.
This may eliminate some uses of the spilled registers, and we don't want to
insert reloads for that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128468 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 17:47:00 +00:00
Jakob Stoklund Olesen
2ef661b0e8 Properly enable rematerialization when spilling after live range splitting.
The instruction to be rematerialized may not be the one defining the register
that is being spilled. The traceSiblingValue() function sees through sibling
copies to find the remat candidate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128449 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 03:12:02 +00:00
Jakob Stoklund Olesen
e9c50732f7 Use individual register classes when spilling snippets.
The main register class may have been inflated by live range splitting, so that
register class is not necessarily valid for the snippet instructions.

Use the original register class for the stack slot interval.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128351 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-26 22:16:41 +00:00
Jakob Stoklund Olesen
682eed0da8 Also eliminate redundant spills downstream of inserted reloads.
This can happen when multiple sibling registers are spilled after live range
splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127965 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-20 05:44:58 +00:00
Jakob Stoklund Olesen
01a46c82e0 Change an argument to a LiveInterval instead of a register number to save some redundant lookups.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127964 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-20 05:44:55 +00:00
Jakob Stoklund Olesen
c1655e1a3c Add debug output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127959 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-19 23:02:47 +00:00
Jakob Stoklund Olesen
2a72bfa1b1 Hoist spills when the same value is known to be in less loopy sibling registers.
Stack slot real estate is virtually free compared to registers, so it is
advantageous to spill earlier even though the same value is now kept in both a
register and a stack slot.

Also eliminate redundant spills by extending the stack slot live range
underneath reloaded registers.

This can trigger a dead code elimination, removing copies and even reloads that
were only feeding spills.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127868 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-18 04:23:06 +00:00
Jakob Stoklund Olesen
6a3dbd3b25 Dead code elimination may separate the live interval into multiple connected components.
I have convinced myself that it can only happen when a phi value dies. When it
happens, allocate new virtual registers for the components.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127827 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-17 20:37:07 +00:00
Jakob Stoklund Olesen
13ba2527f7 Trace back through sibling copies to hoist spills and find rematerializable defs.
After live range splitting, an original value may be available in multiple
registers. Tracing back through the registers containing the same value, find
the best place to insert a spill, determine if the value has already been
spilled, or discover a reaching def that may be rematerialized.

This is only the analysis part. The information is not used for anything yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127698 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-15 21:13:25 +00:00
Jakob Stoklund Olesen
766faf4b2b Rename members to match LLVM naming conventions more closely.
Remove the unused reserved_ bit vector, no functional change intended.

This doesn't break 'svn blame', this file really is all my fault.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127607 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-14 19:56:43 +00:00
Jakob Stoklund Olesen
7792e980c4 Tell the register allocator about new unused virtual registers.
This allows the allocator to free any resources used by the virtual register,
including physical register assignments.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127560 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-13 01:23:11 +00:00
Jakob Stoklund Olesen
b1adbd1f67 Include snippets in the live stack interval.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127530 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-12 04:25:36 +00:00
Jakob Stoklund Olesen
10a433238f Spill multiple registers at once.
Live range splitting can create a number of small live ranges containing only a
single real use. Spill these small live ranges along with the large range they
are connected to with copies. This enables memory operand folding and maximizes
the spill to fill distance.

Work in progress with known bugs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127529 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-12 04:17:20 +00:00
Jakob Stoklund Olesen
47dbf6cef7 Change the Spiller interface to take a LiveRangeEdit reference.
This makes it possible to register delegates and get callbacks when the spiller
edits live ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127389 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-10 01:51:42 +00:00
Jakob Stoklund Olesen
38f6bd0fc8 Make SpillIs an optional pointer. Avoid creating a bunch of temporary SmallVectors.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127388 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-10 01:21:58 +00:00
Jakob Stoklund Olesen
92a55f4bdd Add a LiveRangeEdit::Delegate protocol.
This will we used for keeping register allocator data structures up to date
while LiveRangeEdit is trimming live intervals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127300 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09 00:57:29 +00:00
Jakob Stoklund Olesen
1973b3e254 Make the UselessRegs argument optional in the LiveRangeEdit constructor.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127181 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-07 22:42:16 +00:00
Jakob Stoklund Olesen
b2597268c2 Use the same spill slot for all live ranges that descend form the same original
register.

This avoids some silly stack slot shuffling when both sides of a copy get
spilled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126353 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-24 01:07:55 +00:00
Jakob Stoklund Olesen
75b5409d3a 80 Col.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126258 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-22 23:01:49 +00:00
Jakob Stoklund Olesen
c3dca3f9d4 Set an allocation hint when rematting before a COPY.
This almost guarantees that the COPY will be coalesced.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125140 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 00:25:36 +00:00
Jakob Stoklund Olesen
7b1f498a76 Avoid folding a load instruction into an instruction that redefines the register.
The target hook doesn't know how to do that. (Neither do I).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125108 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-08 19:33:55 +00:00
Jakob Stoklund Olesen
be97e906e0 Teach TargetRegisterInfo how to cram stack slot indexes in with the virtual and
physical register numbers.

This makes the hack used in LiveInterval official, and lets LiveInterval be
oblivious of stack slots.

The isPhysicalRegister() and isVirtualRegister() predicates don't know about
this, so when a variable may contain a stack slot, isStackSlot() should always
be tested first.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123128 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 21:17:37 +00:00
Jakob Stoklund Olesen
390482569c Apparently, operandices is not a word.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122135 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-18 03:28:32 +00:00
Jakob Stoklund Olesen
83d1ba5728 Teach the inline spiller to attempt folding a load instruction into its single
use before rematerializing the load.

This allows us to produce:

    addps	LCPI0_1(%rip), %xmm2

Instead of:

    movaps	LCPI0_1(%rip), %xmm3
    addps	%xmm3, %xmm2

Saving a register and an instruction. The standard spiller already knows how to
do this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122133 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-18 03:04:14 +00:00
Jakob Stoklund Olesen
89cab93fe9 Pass a Banner argument to the machine code verifier both from
createMachineVerifierPass and MachineFunction::verify.

The banner is printed before the machine code dump, just like the printer pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122113 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-18 00:06:56 +00:00
Jakob Stoklund Olesen
3bda29eb4f Rip out live range splitting support from the inline spiller.
The spiller should only spill. The register allocator will drive live range
splitting, it has the needed information about register pressure and
interferences.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121590 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-10 22:54:40 +00:00
Jakob Stoklund Olesen
68257e61eb When spilling a register defined by an early clobber, make sure that the new
live ranges for the spill register are also defined at the use slot instead of
the normal def slot.

This fixes PR8612 for the inline spiller. A use was being allocated to the same
register as a spilled early clobber def.

This problem exists in all the spillers. A fix for the standard spiller is
forthcoming.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@119182 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-15 20:55:49 +00:00
Jakob Stoklund Olesen
e93198af07 Hook up AliasAnalysis in InlineSpiller. This is used for rematerializing
constant loads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118741 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 23:55:56 +00:00
Andrew Trick
f4baeaf848 RABasic is nearly functionally complete. There are a few remaining
benchmarks hitting an assertion.
Adds LiveIntervalUnion::collectInterferingVRegs.
Fixes "late spilling" by checking for any unspillable live vregs among
all physReg aliases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118701 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 19:18:47 +00:00
Jakob Stoklund Olesen
b80e973c95 Simplify the LiveRangeEdit::canRematerializeAt() interface a bit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118661 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 01:05:12 +00:00
Jakob Stoklund Olesen
8c42f48d02 Disable fancy splitting during spilling unless -extra-spiller-splits is given.
This way, InlineSpiller does the same amount of splitting as the standard
spiller. Splitting should really be guided by the register allocator, and
doesn't belong in the spiller at all.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118216 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-04 00:32:32 +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
a37d5cf342 Don't assign new registers created during a split to the same stack slot, but
give them individual stack slots once the are actually spilled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117945 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 19:49:57 +00:00
Jakob Stoklund Olesen
7d57753df3 Print out register class of spilled register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117761 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-30 01:26:09 +00:00
Jakob Stoklund Olesen
1f46a0ac66 Run a verification pass before any splitting to better distribute blame.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117629 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 00:40:55 +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
26b92be922 Add a temporary command line option to verify machine code after each spill or
split.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117597 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28 20:34:47 +00:00