Commit Graph

23 Commits

Author SHA1 Message Date
Dan Gohman
00dc84a2ca Eliminate the loop that walks the critical path. Instead, just track the
position in the critical path during the main instruction walk.  This
eliminates the need for the CritialAntiDep DenseMap.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61096 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-16 19:27:52 +00:00
Dan Gohman
812d7506d0 Enable anti-dependence breaking by default when post-RA scheduling is enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61078 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-16 06:21:45 +00:00
Dan Gohman
fde221fa0a When breaking an anti-dependency, don't use a register which has seen
one of its aliases defined. This is conservative, but tricky subreg
corner cases are outside the primary aim of this pass.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61077 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-16 06:20:58 +00:00
Dan Gohman
3f23744df4 Fix some register-alias-related bugs in the post-RA scheduler liveness
computation code. Also, avoid adding output-depenency edges when both
defs are dead, which frequently happens with EFLAGS defs.

Compute Depth and Height lazily, and always in terms of edge latency
values. For the schedulers that don't care about latency, edge latencies
are set to 1.

Eliminate Cycle and CycleBound, and LatencyPriorityQueue's Latencies array.
These are all subsumed by the Depth and Height fields.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61073 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-16 03:25:46 +00:00
Dan Gohman
54e4c36a73 Rewrite the SDep class, and simplify some of the related code.
The Cost field is removed. It was only being used in a very limited way,
to indicate when the scheduler should attempt to protect a live register,
and it isn't really needed to do that. If we ever want the scheduler to
start inserting copies in non-prohibitive situations, we'll have to
rethink some things anyway.

A Latency field is added. Instead of giving each node a single
fixed latency, each edge can have its own latency. This will eventually
be used to model various micro-architecture properties more accurately.

The PointerIntPair class and an internal union are now used, which
reduce the overall size.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60806 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-09 22:54:47 +00:00
Dan Gohman
2ce7f2068f Drop the reg argument to isRegReDefinedByTwoAddr, which was redundant.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60586 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-05 05:45:42 +00:00
Dan Gohman
490b1833a9 Ignore IMPLICIT_DEF instructions when computing physreg liveness.
While they appear to provide a normal clobbering def, they don't
in the case of the awkward IMPLICIT_DEF+INSERT_SUBREG idiom. It
would be good to change INSERT_SUBREG; until then, this change
allows post-regalloc scheduling to cope in a mildly conservative
way.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60583 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-05 05:30:02 +00:00
Dan Gohman
80e201b8db Use register names instead of numbers in debug output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60525 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-04 02:15:26 +00:00
Dan Gohman
cef874ae2b Rewrite the liveness bookkeeping code to fix a bunch of
issues with subreg operands and tied operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60510 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03 23:07:27 +00:00
Dan Gohman
e96cc775e4 Fix an inconsistency in a comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60500 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03 19:38:38 +00:00
Dan Gohman
e561751e98 Don't charge the full latency for anti and output dependencies. This is
an area where eventually it would be good to use target-dependent
information.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60498 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03 19:37:34 +00:00
Dan Gohman
0dba0e5408 When looking for anti-dependences on the critical path, don't bother
examining non-anti-dependence edges.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60496 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03 19:32:26 +00:00
Dan Gohman
ebb0a31103 Add a comment about callee-saved registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60495 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03 19:30:13 +00:00
Nick Lewycky
a89d102b32 Silence a warning.
Despite changing the order of evaluation, this doesn't actually change the
meaning of the statement.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60177 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-27 17:29:52 +00:00
Dan Gohman
878ef1d5bc Suppress warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60041 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-25 18:53:54 +00:00
Dan Gohman
21d9003087 Initial support for anti-dependence breaking. Currently this code does not
introduce any new spilling; it just uses unused registers.

Refactor the SUnit topological sort code out of the RRList scheduler and
make use of it to help with the post-pass scheduler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59999 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-25 00:52:40 +00:00
Dan Gohman
a1e6d363e5 Factor out the code for verifying the work of the scheduler,
extend it a bit, and make use of it in all schedulers, to
ensure consistent checking.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59689 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-20 01:26:25 +00:00
Dan Gohman
343f0c0467 Experimental post-pass scheduling support. Post-pass scheduling
is currently off by default, and can be enabled with
-disable-post-RA-scheduler=false.

This doesn't have a significant impact on most code yet because it doesn't
yet do anything to address anti-dependencies and it doesn't attempt to
disambiguate memory references. Also, several popular targets
don't have pipeline descriptions yet.

The majority of the changes here are splitting the SelectionDAG-specific
code out of ScheduleDAG, so that ScheduleDAG can be moved to
libLLVMCodeGen.a. The interface between ScheduleDAG-using code and
the rest of the scheduling code is somewhat rough and will evolve.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59676 91177308-0d34-0410-b5e6-96231b3b80d8
2008-11-19 23:18:57 +00:00
Dan Gohman
ae73dc1448 Tidy up several unbeseeming casts from pointer to intptr_t.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55779 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-04 17:05:41 +00:00
Chris Lattner
459525df1e don't create the post-ra scheduler unless it is enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45972 91177308-0d34-0410-b5e6-96231b3b80d8
2008-01-14 19:00:06 +00:00
Chris Lattner
4ee451de36 Remove attribution from file headers, per discussion on llvmdev.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45418 91177308-0d34-0410-b5e6-96231b3b80d8
2007-12-29 20:36:04 +00:00
Dale Johannesen
72f1596403 Modify previous patch per review comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@39817 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-13 17:31:29 +00:00
Dale Johannesen
e7e7d0d7e3 Skeleton of post-RA scheduler; doesn't do anything yet.
Change name of -sched option and DEBUG_TYPE to
pre-RA-sched; adjust testcases.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@39816 91177308-0d34-0410-b5e6-96231b3b80d8
2007-07-13 17:13:54 +00:00