Commit Graph

30 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
f42b66169d Update LiveDebugVariables after live range splitting.
After a virtual register is split, update any debug user variables that resided
in the old register. This ensures that the LiveDebugVariables are still correct
after register allocation.

This may create DBG_VALUE instructions that place a user variable in a register
in parts of the function and in a stack slot in other parts. DwarfDebug
currently doesn't support that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130998 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-06 18:00:02 +00:00
Jakob Stoklund Olesen
bb30dd40ed Minimize the slot indexes spanned by register ranges created when splitting.
When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.

Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.

This fixes PR9823.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130687 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-02 05:29:58 +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
3520019931 When dead code elimination removes all but one use, try to fold the single def into the remaining use.
Rematerialization can leave single-use loads behind that we might as well fold whenever possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128918 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 20:20:26 +00:00
Jakob Stoklund Olesen
f22ca3fe5f Treat clones the same as their origin.
When DCE clones a live range because it separates into connected components,
make sure that the clones enter the same register allocator stage as the
register they were cloned from.

For instance, clones may be split even when they where created during spilling.
Other registers created during spilling are not candidates for splitting or even
(re-)spilling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128524 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-30 02:52:39 +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
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
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
1d5b845081 Add a LiveRangeEdit delegate callback before shrinking a live range.
The register allocator needs to adjust its live interval unions when that happens.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127774 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-16 22:56:16 +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
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
Matt Beaumont-Gay
ab2ee2ea75 Add a virtual dtor to Delegate to silence -Wnon-virtual-dtor
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127311 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09 04:02:15 +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
5881799d0c Delete dead code after rematerializing.
LiveRangeEdit::eliminateDeadDefs() will eventually be used by coalescing,
splitting, and spilling for dead code elimination. It can delete chains of dead
instructions as long as there are no dependency loops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127287 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-08 22:46:11 +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
4670353a21 Transfer simply defined values directly without recomputing liveness and SSA.
Values that map to a single new value in a new interval after splitting don't
need new PHIDefs, and if the parent value was never rematerialized the live
range will be the same.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126894 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 23:05:19 +00:00
Jakob Stoklund Olesen
fd38917d4d This method belonged in VirtRegMap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126002 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19 00:38:43 +00:00
Jakob Stoklund Olesen
e324f6e05f Use VirtRegMap's Virt2SplitMap to keep track of the original live range before splitting.
All new virtual registers created for spilling or splitting point back to their original.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125980 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-18 22:35:20 +00:00
Eric Christopher
0f43811903 Reapply this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124779 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 06:18:29 +00:00
Eric Christopher
463a2977b1 Temporarily revert 124765 in an attempt to find the cycle breaking bootstrap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124778 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 05:40:54 +00:00
Jakob Stoklund Olesen
2cd2111959 Defer SplitKit value mapping until all defs are available.
The greedy register allocator revealed some problems with the value mapping in
SplitKit. We would sometimes start mapping values before all defs were known,
and that could change a value from a simple 1-1 mapping to a multi-def mapping
that requires ssa update.

The new approach collects all defs and register assignments first without
filling in any live intervals. Only when finish() is called, do we compute
liveness and mapped values. At this time we know with certainty which values map
to multiple values in a split range.

This also has the advantage that we can compute live ranges based on the
remaining uses after rematerializing at split points.

The current implementation has many opportunities for compile time optimization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124765 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 00:54:23 +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
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
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
db4eec3d2c Fix sign error.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117677 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 18:21:18 +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
080c316ff8 Move some of the InlineSpiller rematerialization code into LiveRangeEdit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116951 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-20 22:00:51 +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