Commit Graph

162 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
c321a20b2e Split loop exiting edges more aggressively.
PHIElimination splits critical edges when it predicts it can resolve
interference and eliminate copies. It doesn't split the edge if the
interference wouldn't be resolved anyway because the phi-use register is
live in the critical edge anyway.

Teach PHIElimination to split loop exiting edges with interference, even
if it wouldn't resolve the interference. This removes the necessary
copies from the loop, which is still an improvement from injecting the
copies into the loop.

The test case demonstrates the improvement. Before:

LBB0_1:
  cmpb  $0, (%rdx)
  leaq  1(%rdx), %rdx
  movl  %esi, %eax
  je  LBB0_1

After:

LBB0_1:
  cmpb  $0, (%rdx)
  leaq  1(%rdx), %rdx
  je  LBB0_1

  movl  %esi, %eax

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160571 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-20 20:49:53 +00:00
Jakob Stoklund Olesen
9e51b14faa Allow multiple terminators to read virtual registers.
Find the kill as the last terminator to read SrcReg.

Patch by Philipp Brüschweiler!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159722 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-04 19:52:05 +00:00
Jakob Stoklund Olesen
5213750e27 Teach PHIElimination to handle <undef> operands.
When a PHI use is <undef>, don't emit a copy in the predecessor block,
but insert an IMPLICIT_DEF instruction instead. This ensures that
virtual register uses are always jointly dominated by defs, even if some
of them are IMPLICIT_DEF.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159121 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-25 03:36:12 +00:00
Andrew Trick
8dd26253f5 RegAlloc superpass: includes phi elimination, coalescing, and scheduling.
Creates a configurable regalloc pipeline.

Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa.

When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>.

CodeGen transformation passes are never "required" as an analysis

ProcessImplicitDefs does not require LiveVariables.

We have a plan to massively simplify some of the early passes within the regalloc superpass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150226 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-10 04:10:36 +00:00
Jakob Stoklund Olesen
4888d5e98c Delete an unused member variable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148594 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20 22:48:59 +00:00
Evan Cheng
7c2a4a30e0 First chunk of MachineInstr bundle support.
1. Added opcode BUNDLE
2. Taught MachineInstr class to deal with bundled MIs
3. Changed MachineBasicBlock iterator to skip over bundled MIs; added an iterator to walk all the MIs
4. Taught MachineBasicBlock methods about bundled MIs


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145975 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-06 22:12:01 +00:00
Jakob Stoklund Olesen
73e7dced38 Add an isSSA() flag to MachineRegisterInfo.
This flag is true from isel to register allocation when the machine
function is required to be in SSA form.  The TwoAddressInstructionPass
and PHIElimination passes clear the flag.

The SSA flag wil be used by the machine code verifier to check for SSA
form, and eventually an assertion can enforce it in +Asserts builds.
This will catch the common target error of creating machine code with
multiple defs of a virtual register.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136532 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-29 22:51:22 +00:00
Jay Foad
ddcdcc8863 Remove unused STL header includes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130068 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-23 19:53:52 +00:00
Cameron Zwarich
6a951ac63f Add an option to disable critical edge splitting in PHIElimination.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127398 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-10 05:59:17 +00:00
Cameron Zwarich
61a733434d Adjust indenting of arguments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125727 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 06:13:46 +00:00
Cameron Zwarich
688521ca6f Return Changed from SplitPHIEdges rather than always returning true.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125726 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 06:13:43 +00:00
Cameron Zwarich
117be03cc6 Add a statistic to PHIElimination tracking the number of critical edges split.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125476 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-14 02:09:11 +00:00
Jakob Stoklund Olesen
04223909b7 Try for the third time to teach getFirstTerminator() about debug values.
This time let's rephrase to trick gcc-4.3 into not miscompiling.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123432 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14 06:33:45 +00:00
Jakob Stoklund Olesen
b6436e5be1 Revert r123419. It still breaks llvm-gcc-i386-linux-selfhost.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123423 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14 02:12:54 +00:00
Jakob Stoklund Olesen
09befe9036 Try again to teach getFirstTerminator() about debug values.
Fix some callers to better deal with debug values.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123419 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14 01:17:53 +00:00
Devang Patel
a851fd8cd8 Speculatively revert r123384 to make llvm-gcc-i386-linux-selfhost buildbot happy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123389 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-13 19:27:50 +00:00
Jakob Stoklund Olesen
64f865ceca Teach MachineBasicBlock::getFirstTerminator to ignore debug values.
It will still return an iterator that points to the first terminator or end(),
but there may be DBG_VALUE instructions following the first terminator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123384 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-13 18:41:05 +00:00
Jakob Stoklund Olesen
4314268128 Replace TargetRegisterInfo::printReg with a PrintReg class that also works without a TRI instance.
Print virtual registers numbered from 0 instead of the arbitrary
FirstVirtualRegister. The first virtual register is printed as %vreg0.
TRI::NoRegister is printed as %noreg.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123107 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09 03:05:53 +00:00
Cameron Zwarich
0a3fdd6e11 Remove the PHIElimination.h header, as it is no longer needed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120959 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-05 21:39:42 +00:00
Cameron Zwarich
a474685d06 Move the FindCopyInsertPoint method of PHIElimination to a new standalone
function so that it can be shared with StrongPHIElimination.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120951 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-05 19:51:05 +00:00
Cameron Zwarich
2a7942926b Remove PHIElimination's private copy of SkipPHIsAndLabels.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120918 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-04 20:40:15 +00:00
Owen Anderson
ce665bd2e2 Now with fewer extraneous semicolons!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 22:25:06 +00:00
Owen Anderson
02dd53e1c5 Now that PassInfo and Pass::ID have been separated, move the rest of the passes over to the new registration API.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111815 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-23 17:52:01 +00:00
Jakob Stoklund Olesen
9ac248848f Preserve subregs on PHI source operands. Patch by Krister Wombell!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111366 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-18 16:09:47 +00:00
Evan Cheng
148341cc9b PHI elimination shouldn't require machineloopinfo since it's used at -O0. Move the requirement to LiveIntervalAnalysis instead. Note this does not change the number of times machineloopinfo is computed.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111285 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17 21:00:37 +00:00
Evan Cheng
e008384508 Move the decision logic whether it's a good idea to split a critical edge to clients. Also fixed an erroneous check. An edge is only a back edge when the from and to blocks are in the same loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111256 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17 17:43:50 +00:00
Evan Cheng
97b9b97853 PHI elimination should not break back edge. It can cause some significant code placement issues. rdar://8263994
good:
LBB0_2:
  mov     r2, r0
  . . .
  mov     r1, r2
  bne     LBB0_2

bad:
LBB0_2:
  mov     r2, r0
  . . .
@ BB#3:
  mov     r1, r2
  b       LBB0_2


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111221 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17 01:20:36 +00:00
Owen Anderson
90c579de5a Reapply r110396, with fixes to appease the Linux buildbot gods.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110460 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 18:33:48 +00:00
Owen Anderson
1f74590e9d Revert r110396 to fix buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110410 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06 00:23:35 +00:00
Owen Anderson
9ccaf53ada Don't use PassInfo* as a type identifier for passes. Instead, use the address of the static
ID member as the sole unique type identifier.  Clean up APIs related to this change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110396 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-05 23:42:04 +00:00
Jakob Stoklund Olesen
92c1f72c54 Emit COPY instructions instead of using copyRegToReg in InstrEmitter,
ScheduleDAGEmit, TwoAddressLowering, and PHIElimination.

This switches the bulk of register copies to using COPY, but many less used
copyRegToReg calls remain.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108050 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-10 19:08:25 +00:00
Dan Gohman
853d3fb8d2 Move PHIElimination's SplitCriticalEdge for MachineBasicBlocks out
into a utility routine, teach it how to update MachineLoopInfo, and
make use of it in MachineLICM to split critical edges on demand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106555 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-22 17:25:57 +00:00
Stuart Hastings
3bf9125933 Add a DebugLoc parameter to TargetInstrInfo::InsertBranch(). This
addresses a longstanding deficiency noted in many FIXMEs scattered
across all the targets.

This effectively moves the problem up one level, replacing eleven
FIXMEs in the targets with eight FIXMEs in CodeGen, plus one path
through FastISel where we actually supply a DebugLoc, fixing Radar
7421831.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106243 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-17 22:43:56 +00:00
Dan Gohman
34dcc6fadc Add a DebugLoc argument to TargetInstrInfo::copyRegToReg, so that it
doesn't have to guess.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103194 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-06 20:33:48 +00:00
Evan Cheng
3d720fbc6a Move REG_SEQUENCE removal to 2addr pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103109 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-05 18:45:40 +00:00
Evan Cheng
afff40a62d Teach PHI elimination to remove REG_SEQUENCE instructions and update references of the source operands with references of the destination with subreg indices. e.g.
%reg1029<def>, %reg1030<def> = VLD1q16 %reg1024<kill>, ...
%reg1031<def> = REG_SEQUENCE %reg1029<kill>, 5, %reg1030<kill>, 6
=>
%reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ...

PHI elimination now does more than phi elimination. It is really a de-SSA pass.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103039 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-04 20:26:52 +00:00
Evan Cheng
28428cd6f3 Rename variables for consistency.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103013 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-04 17:12:26 +00:00
Evan Cheng
48f2cb926e Avoid being influenced by dbg_value instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99465 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-25 01:01:37 +00:00
Evan Cheng
a92dced4a1 Remove PHINodeTraits and use MachineInstrExpressionTrait instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97687 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03 23:55:49 +00:00
Jakob Stoklund Olesen
dcfe5f30b5 Keep track of phi join registers explicitly in LiveVariables.
Previously, LiveIntervalAnalysis would infer phi joins by looking for multiply
defined registers. That doesn't work if the phi join is implicitly defined in
all but one of the predecessors.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96994 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-23 22:43:58 +00:00
Jakob Stoklund Olesen
f895dbeb29 Dead code elimination
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96837 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-23 00:28:53 +00:00
Jakob Stoklund Olesen
1bf1691ed3 Dead code elimination.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96496 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-17 19:13:56 +00:00
Chris Lattner
518bb53485 move target-independent opcodes out of TargetInstrInfo
into TargetOpcodes.h.  #include the new TargetOpcodes.h
into MachineInstr.  Add new inline accessors (like isPHI())
to MachineInstr, and start using them throughout the 
codebase.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95687 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-09 19:54:29 +00:00
David Greene
f788297942 Change errs() to dbgs().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92566 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05 01:24:24 +00:00
Bill Wendling
3de8249078 Turn off critical edge splitting for landing pads. The introduction of a
non-landing pad basic block as the successor to a block that ends in an
unconditional jump will cause block folding to remove the added block as a
successor. Thus eventually removing it AND the landing pad entirely. Critical
edge splitting is an optimization, so we can safely turn it off when dealing
with landing pads.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91634 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-17 23:42:32 +00:00
Jakob Stoklund Olesen
74215fc29f Reuse lowered phi nodes.
Tail duplication produces lots of identical phi nodes in different basic
blocks. Teach PHIElimination to reuse the join registers when lowering a phi
node that is identical to an already lowered node. This saves virtual
registers, and more importantly it avoids creating copies the the coalescer
doesn't know how to eliminate.

Teach LiveIntervalAnalysis about the phi joins with multiple uses.

This patch significantly reduces code size produced by -pre-regalloc-taildup.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91549 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-16 18:55:53 +00:00
Chris Lattner
7896c9f436 improve portability to avoid conflicting with std::next in c++'0x.
Patch by Howard Hinnant!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-03 00:50:42 +00:00
Jakob Stoklund Olesen
8f72235a77 Move PHIElimination::isLiveOut method to LiveVariables.
We want LiveVariables clients to use methods rather than accessing the
getVarInfo data structure directly. That way it will be possible to change the
LiveVariables representation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90240 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-01 17:13:31 +00:00
Jakob Stoklund Olesen
323d8c3ed7 Be more clever about calculating live variables through new basic blocks.
When splitting a critical edge, the registers live through the edge are:

- Used in a PHI instruction, or
- Live out from the predecessor, and
- Live in to the successor.

This allows the coalescer to eliminate even more phi joins.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89530 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-21 02:05:21 +00:00
Jakob Stoklund Olesen
160069d15a Place new basic blocks immediately after their predecessor when splitting
critical edges in PHIElimination.

This has a huge impact on regalloc performance, and we recover almost all of
the 10% compile time regression that edge splitting introduced.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89381 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-19 19:42:16 +00:00