Commit Graph

114 Commits

Author SHA1 Message Date
David Goodwin 17199b56b0 Remove -post-RA-schedule flag and add a TargetSubtarget method to enable post-register-allocation scheduling. By default it is off. For ARM, enable/disable with -mattr=+/-postrasched. Enable by default for cortex-a8.
llvm-svn: 83122
2009-09-30 00:10:16 +00:00
Jakob Stoklund Olesen 0bb5af345a Use KILL instead of IMPLICIT_DEF in LowerSubregs pass.
llvm-svn: 83007
2009-09-28 20:32:46 +00:00
David Goodwin a4c98a3e34 Fix bug in kill flag updating for post-register-allocation scheduling. When the kill flag of a superreg needs to be cleared because there are one or more subregs live, we instead add implicit-defs of those subregs and leave the kill flag on the superreg. This allows us to end the live-range of the superreg without ending the live-ranges of the subregs.
llvm-svn: 82629
2009-09-23 16:35:25 +00:00
Evan Cheng 270d0f986f Enhance EmitInstrWithCustomInserter() so target can specify CFG changes that sdisel will use to properly complete phi nodes.
Not functionality change yet.

llvm-svn: 82273
2009-09-18 21:02:19 +00:00
Benjamin Kramer e3c9d23bea It's a bool, so treat it like one. Fixes a MSVC warning.
llvm-svn: 81112
2009-09-06 12:10:17 +00:00
David Goodwin 6c08cfcfa0 Create our own block initializer for kill fixups as the scheduling one wasn't doing the right thing.
llvm-svn: 80958
2009-09-03 22:15:25 +00:00
David Goodwin 7f6516949b Add hidden flags to allow binary search of post-RA scheduling errors.
llvm-svn: 80702
2009-09-01 18:34:03 +00:00
David Goodwin c8985204d9 Don't mark a register live at an undef use.
llvm-svn: 80621
2009-08-31 20:47:02 +00:00
David Goodwin 7cb103dc8b Another stab at fixing up register kill flags after post-RA scheduling.
llvm-svn: 80410
2009-08-29 00:11:13 +00:00
David Goodwin ae6bc8214a Fixup register kills after scheduling.
llvm-svn: 80002
2009-08-25 17:03:05 +00:00
Chris Lattner 4883d90396 convert LoopInfo.h and GraphWriter.h to use raw_ostream
llvm-svn: 79836
2009-08-23 07:19:13 +00:00
David Goodwin 1f8c7a76f7 Fix counting of Post-RA scheduling stalls. Improve debug output.
llvm-svn: 78843
2009-08-12 21:47:46 +00:00
Dan Gohman 2a767c0d26 This logic was accidentally inverted in r78767.
llvm-svn: 78773
2009-08-12 01:44:20 +00:00
Dan Gohman f7912edba5 Factor out the code for finding an available register for use
in breaking an anti-dependence into a separate function.

llvm-svn: 78767
2009-08-12 01:33:27 +00:00
David Goodwin 92492f2f8e Use DEBUG macro for debug output.
llvm-svn: 78694
2009-08-11 17:56:42 +00:00
David Goodwin ebd694bb0a Add some debug output.
llvm-svn: 78687
2009-08-11 17:35:23 +00:00
David Goodwin f20236ac83 Replace DOUT.
llvm-svn: 78634
2009-08-11 01:44:26 +00:00
David Goodwin 6021b4dccc Post RA scheduler changes. Introduce a hazard recognizer that uses the target schedule information to accurately model the pipeline. Update the scheduler to correctly handle multi-issue targets.
llvm-svn: 78563
2009-08-10 15:55:25 +00:00
Dan Gohman 0402315d41 Use setPreservesAll and setPreservesCFG in CodeGen passes.
llvm-svn: 77754
2009-07-31 23:37:33 +00:00
Chris Lattner 7667332899 inline the global 'getInstrOperandRegClass' function into its callers
now that TargetOperandInfo does the heavy lifting.

llvm-svn: 77508
2009-07-29 21:36:49 +00:00
Torok Edwin fbcc663cbf llvm_unreachable->llvm_unreachable(0), LLVM_UNREACHABLE->llvm_unreachable.
This adds location info for all llvm_unreachable calls (which is a macro now) in
!NDEBUG builds.
In NDEBUG builds location info and the message is off (it only prints
"UREACHABLE executed").

llvm-svn: 75640
2009-07-14 16:55:14 +00:00
Torok Edwin 56d0659726 assert(0) -> LLVM_UNREACHABLE.
Make llvm_unreachable take an optional string, thus moving the cerr<< out of
line.
LLVM_UNREACHABLE is now a simple wrapper that makes the message go away for
NDEBUG builds.

llvm-svn: 75379
2009-07-11 20:10:48 +00:00
Evan Cheng 1ff2727c95 Move getInstrOperandRegClass from the scheduler to TargetInstrInfo.
llvm-svn: 70950
2009-05-05 00:30:09 +00:00
Bob Wilson 51856173c8 Fix pr3954. The register scavenger asserts for inline assembly with
register destinations that are tied to source operands.  The
TargetInstrDescr::findTiedToSrcOperand method silently fails for inline
assembly.  The existing MachineInstr::isRegReDefinedByTwoAddr was very
close to doing what is needed, so this revision makes a few changes to
that method and also renames it to isRegTiedToUseOperand (for consistency
with the very similar isRegTiedToDefOperand and because it handles both
two-address instructions and inline assembly with tied registers).

llvm-svn: 68714
2009-04-09 17:16:43 +00:00
Duncan Sands be69d60d54 Add parentheses to pacify gcc-4.3.
llvm-svn: 66653
2009-03-11 09:04:34 +00:00
Dan Gohman 64613aceed Fix a post-RA scheduling liveness bug. When a basic block is being
scheduled in multiple regions, liveness data used by the
anti-dependence breaker is carried from one region to the next, however
the information reflects the state of the instructions before scheduling.
After scheduling, there may be new live range overlaps. Handle this by
pessimizing the liveness data carried between regions to the point where
it will be conservatively correct now matter how the earlier region is
scheduled. This fixes a miscompilation in 176.gcc with the post-RA
scheduler enabled.

llvm-svn: 66558
2009-03-10 18:10:43 +00:00
Dan Gohman dfaf646c34 When scheduling a block in parts, keep track of the overall
instruction index across each part. Instruction indices are used
to make live range queries, and live ranges can extend beyond
scheduling region boundaries.

Refactor the ScheduleDAGSDNodes class some more so that it
doesn't have to worry about this additional information.

llvm-svn: 64288
2009-02-11 04:27:20 +00:00
Dan Gohman b3dbb21df1 Consider any instruction that modifies the stack pointer to be
a scheduling region boundary.  This isn't necessary for
correctness; it helps with compile time, as it avoids the need
for data- and anti-dependencies from all spills and reloads on
the stack-pointer modification.

llvm-svn: 64255
2009-02-10 23:29:38 +00:00
Dan Gohman b95434356c Factor out more code for computing register live-range informationfor
scheduling, and generalize is so that preserves state across
scheduling regions. This fixes incorrect live-range information around
terminators and labels, which are effective region boundaries.

In place of looking for terminators to anchor inter-block dependencies,
introduce special entry and exit scheduling units for this purpose.

llvm-svn: 64254
2009-02-10 23:27:53 +00:00
Evan Cheng 066757eea1 Move getPointerRegClass from TargetInstrInfo to TargetRegisterInfo.
llvm-svn: 63938
2009-02-06 17:43:24 +00:00
Dan Gohman f4b08b4f6c Move ScheduleDAGInstrs.h to be a private header. Front-ends
that used this header to select a scheduling policy should
use SchedulerRegistry.h instead (llvm-gcc and clang were
updated a while ago).

llvm-svn: 63934
2009-02-06 17:12:10 +00:00
Dan Gohman d564353193 Change the post-RA scheduler to iterate through the
basic-block segments bottom-up instead of top down. This
is the first step in a general restructuring of the way
register liveness is tracked in the post-RA scheduler.

llvm-svn: 63643
2009-02-03 18:57:45 +00:00
Dan Gohman 5f8a2598b2 Instead of adding dependence edges between terminator instructions
and every other instruction in their blocks to keep the terminator
instructions at the end, teach the post-RA scheduler how to operate
on ranges of instructions, and exclude terminators from the range
of instructions that get scheduled.

Also, exclude mid-block labels, such as EH_LABEL instructions, and
schedule code before them separately from code after them. This
fixes problems with the post-RA scheduler moving code past
EH_LABELs.

llvm-svn: 62366
2009-01-16 22:10:20 +00:00
Dan Gohman 157e008816 If an anti-dependence uses a non-allocatable register, set AntiDepReg
to 0, to ensure that the subsequent code doesn't try to break the
dependence.

llvm-svn: 62365
2009-01-16 21:57:43 +00:00
Dan Gohman 014142fd1a Fix the check for an empty basic block to check for an empty SUnits
array instead, since this is what the scheduler actually cares about.
And remove a check that is unnecessary, since it can assume that
SUnits isn't empty.

llvm-svn: 62362
2009-01-16 21:37:14 +00:00
Dan Gohman b903071735 Fix a "comparison between signed and unsigned integer expressions"
warning.

llvm-svn: 62327
2009-01-16 17:55:08 +00:00
Dan Gohman ceac7c34f1 Initial hazard recognizer support in post-pass scheduling. This includes
a new toy hazard recognizier heuristic which attempts to direct the
scheduler to avoid clumping large groups of loads or stores too densely.

llvm-svn: 62291
2009-01-16 01:33:36 +00:00
Dan Gohman 619ef48a52 Move a few containers out of ScheduleDAGInstrs::BuildSchedGraph
and into the ScheduleDAGInstrs class, so that they don't get
destructed and re-constructed for each block. This fixes a
compile-time hot spot in the post-pass scheduler.

To help facilitate this, tidy and do some minor reorganization
in the scheduler constructor functions.

llvm-svn: 62275
2009-01-15 19:20:50 +00:00
Dan Gohman 906152a20f Tidy up #includes, deleting a bunch of unnecessary #includes.
llvm-svn: 61715
2009-01-05 17:59:02 +00:00
Dan Gohman 04543e719e Rename BuildSchedUnits to BuildSchedGraph, and refactor the
code in ScheduleDAGSDNodes' BuildSchedGraph into separate functions.

llvm-svn: 61376
2008-12-23 18:36:58 +00:00
Dan Gohman 650b1e7ff8 Use ~0u instead of -1u as the special value, to hopefully avoid
warnings on compilers that warn about such things.

llvm-svn: 61263
2008-12-19 22:23:43 +00:00
Dan Gohman b4d41e802f 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.

llvm-svn: 61096
2008-12-16 19:27:52 +00:00
Dan Gohman 51559185f1 Enable anti-dependence breaking by default when post-RA scheduling is enabled.
llvm-svn: 61078
2008-12-16 06:21:45 +00:00
Dan Gohman 4302b4a63c 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.

llvm-svn: 61077
2008-12-16 06:20:58 +00:00
Dan Gohman dddc1ac7ea 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.

llvm-svn: 61073
2008-12-16 03:25:46 +00:00
Dan Gohman 2d170896ee 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.

llvm-svn: 60806
2008-12-09 22:54:47 +00:00
Dan Gohman d24be45d99 Drop the reg argument to isRegReDefinedByTwoAddr, which was redundant.
llvm-svn: 60586
2008-12-05 05:45:42 +00:00
Dan Gohman c1dee225d0 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.

llvm-svn: 60583
2008-12-05 05:30:02 +00:00
Dan Gohman 44f57df254 Use register names instead of numbers in debug output.
llvm-svn: 60525
2008-12-04 02:15:26 +00:00
Dan Gohman 84efaf6a63 Rewrite the liveness bookkeeping code to fix a bunch of
issues with subreg operands and tied operands.

llvm-svn: 60510
2008-12-03 23:07:27 +00:00
Dan Gohman 0c91a5f56c Fix an inconsistency in a comment.
llvm-svn: 60500
2008-12-03 19:38:38 +00:00
Dan Gohman 434a3ca8e9 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.

llvm-svn: 60498
2008-12-03 19:37:34 +00:00
Dan Gohman 444baea236 When looking for anti-dependences on the critical path, don't bother
examining non-anti-dependence edges.

llvm-svn: 60496
2008-12-03 19:32:26 +00:00
Dan Gohman 1a32dda4aa Add a comment about callee-saved registers.
llvm-svn: 60495
2008-12-03 19:30:13 +00:00
Nick Lewycky 2c96bdd8d6 Silence a warning.
Despite changing the order of evaluation, this doesn't actually change the
meaning of the statement.

llvm-svn: 60177
2008-11-27 17:29:52 +00:00
Dan Gohman bb1298e6d4 Suppress warnings.
llvm-svn: 60041
2008-11-25 18:53:54 +00:00
Dan Gohman ad2134d45d 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.

llvm-svn: 59999
2008-11-25 00:52:40 +00:00
Dan Gohman 4ce15e12b9 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.

llvm-svn: 59689
2008-11-20 01:26:25 +00:00
Dan Gohman 60cb69e665 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.

llvm-svn: 59676
2008-11-19 23:18:57 +00:00
Dan Gohman a79db30d28 Tidy up several unbeseeming casts from pointer to intptr_t.
llvm-svn: 55779
2008-09-04 17:05:41 +00:00
Chris Lattner 994718417a don't create the post-ra scheduler unless it is enabled.
llvm-svn: 45972
2008-01-14 19:00:06 +00:00
Chris Lattner f3ebc3f3d2 Remove attribution from file headers, per discussion on llvmdev.
llvm-svn: 45418
2007-12-29 20:36:04 +00:00
Dale Johannesen 4dc35dbd3e Modify previous patch per review comments.
llvm-svn: 39817
2007-07-13 17:31:29 +00:00
Dale Johannesen 2182f06f2d Skeleton of post-RA scheduler; doesn't do anything yet.
Change name of -sched option and DEBUG_TYPE to
pre-RA-sched; adjust testcases.

llvm-svn: 39816
2007-07-13 17:13:54 +00:00