Commit Graph

14 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
ff3ae8691c Thinking about it, we don't need MachineDominatorTree after all. The DomValue
map discovers the iterated dominance frontier for free.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111400 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-18 20:29:53 +00:00
Jakob Stoklund Olesen
1407c84242 Add the LiveIntervalMap class. Don't hook it up yet.
LiveIntervalMap maps values from a parent LiveInterval to a child interval that
is a strict subset. It will create phi-def values as needed to preserve the
VNInfo SSA form in the child interval.

This leads to an algorithm very similar to the one in SSAUpdaterImpl.h, but with
enough differences that the code can't be reused:

- We don't need to manipulate PHI instructions.
- LiveIntervals have kills.
- We have MachineDominatorTree.
- We can use df_iterator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111393 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-18 19:00:08 +00:00
Jakob Stoklund Olesen
0a2b2a1497 Clean up the Spiller.h interface.
The earliestStart argument is entirely specific to linear scan allocation, and
can be easily calculated by RegAllocLinearScan.

Replace std::vector with SmallVector.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111055 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-13 22:56:53 +00:00
Jakob Stoklund Olesen
fc412d85c4 Implement splitting inside a single block.
When a live range is contained a single block, we can split it around
instruction clusters. The current approach is very primitive, splitting before
and after the largest gap between uses.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111043 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-13 21:18:48 +00:00
Jakob Stoklund Olesen
2dee7a527b Update the SplitAnalysis statistics as uses are moved from curli to the new
split intervals. THis means the analysis can be used for multiple splits as long
as curli doesn't shrink.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110975 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-12 23:02:55 +00:00
Jakob Stoklund Olesen
f1b05f2b0e Implement single block splitting.
Before spilling a live range, we split it into a separate range for each basic
block where it is used. That way we only get one reload per basic block if the
new smaller ranges can allocate to a register.

This type of splitting is already present in the standard spiller.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110934 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-12 17:07:14 +00:00
Jakob Stoklund Olesen
08e93b14c3 Recalculate the spill weight and allocation hint for virtual registers created
during live range splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110686 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-10 17:07:22 +00:00
Jakob Stoklund Olesen
5eb308b944 Lazily defer duplicating the live interval we are splitting until we know it is
necessary.

Sometimes, live range splitting doesn't shrink the current interval, but simply
changes some instructions to use a new interval. That makes the original more
suitable for spilling. In this case, we don't need to duplicate the original.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110481 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 22:17:33 +00:00
Jakob Stoklund Olesen
7536f72a97 Checkpoint SplitKit progress.
We are now at a point where we can split around simple single-entry, single-exit
loops, although still with some bugs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110257 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-04 22:08:39 +00:00
Jakob Stoklund Olesen
f0179004e9 Add SplitEditor to SplitKit. This class will be used to edit live intervals and
rewrite instructions for live range splitting.

Still work in progress.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109469 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-26 23:44:11 +00:00
Jakob Stoklund Olesen
f2c6e367c1 Change the createSpiller interface to take a MachineFunctionPass argument.
The spillers can pluck the analyses they need from the pass reference.

Switch some never-null pointers to references.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108969 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-20 23:50:15 +00:00
Jakob Stoklund Olesen
6a0dc079ef Implement loop splitting analysis.
Determine which loop exit blocks need a 'pre-exit' block inserted.
Recognize when this would be impossible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108941 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-20 21:46:58 +00:00
Jakob Stoklund Olesen
abff28087f Appease the colonials.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108845 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-20 16:12:37 +00:00
Jakob Stoklund Olesen
8ae0263471 Beginning SplitKit - utility classes for live range splitting.
This is a work in progress. So far we have some basic loop analysis to help
determine where it is useful to split a live range around a loop.

The actual loop splitting code from Splitter.cpp is also going to move in here.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108842 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-20 15:41:07 +00:00