llvm-svn: 52744

    ,------.
    |      |
    |      v
    |   t2 = phi ... t1 ...
    |      |
    |      v
    |   t1 = ...
    |  ... = ... t1 ...
    |      |
    `------'

where there is a use in a PHI node that's a predecessor to the defining
block. We don't want to mark all predecessors as having the value "alive" in
this case. Also, the assert was too restrictive and didn't handle this case.

llvm-svn: 52655

Rewrite LiveVariable liveness computation. The new implementation is much simplified. It eliminated the nasty recursive routines and removed the partial def / use bookkeeping. There is also potential for performance improvement by replacing the conservative handling of partial physical register definitions. The code is currently disabled until live interval analysis is taught of the name scheme.

This patch also fixed a couple of nasty corner cases.

llvm-svn: 49784

Now that I am told MachineRegisterInfo also tracks physical register uses / defs, I can do away with the horribleness I introduced a while back. It's impossible to detect if there is any use of a physical register below an instruction (and before any def of the register) with some cheap book keeping.

llvm-svn: 49105

1. If part of a register is re-defined, an implicit kill and an implicit def are added to denote read / mod / write. However, this should only be necessary if the register is actually read later. This is a performance issue.
2. If a sub-register is being defined, and it doesn't have a previous use, do not add a implicit kill to the last use of a super-register:
   = EAX, AX<imp-use,kill>
...
AX =
In this case, EAX is live but AX is killed, this is wrong and will cause the coalescer to do bad things.

llvm-svn: 48521

findRegisterUseOperandIdx, findRegisterDefOperandIndx. Fix some naming inconsistencies.

llvm-svn: 47927

llvm-svn: 47453

No need to go up more levels. A def of a register also sets its sub-registers
(so if PhysRegInfo[SuperReg] is NULL, it means SuperReg's super registers are
not previously defined).

llvm-svn: 47399

llvm-svn: 47395

llvm-svn: 47389

Added two "FIXMEs" for code that looks dubious to me (but I could be
wrong).

llvm-svn: 47366

changes. (Sorry for any formatting changes that creeped in.)

llvm-svn: 47362

 - Constified some MachineOperand values.
 - Added/Modified some comments.

llvm-svn: 47358

llvm-svn: 46930

If a vr is already marked alive in a bb, then it has PHI uses that are visited earlier, then it is not killed in the def block (i.e. not dead).

llvm-svn: 46763

Move some functionality for adding flags to MachineInstr's into methods on MachineInstr rather than LiveVariables.

llvm-svn: 46295

Move some calls to getVRegDef higher in the callgraph, so they don't get executed as frequently in performance sensitive code.

llvm-svn: 46027

llvm-svn: 46016

Make MachineInstr::getDesc return a reference instead
of a pointer, since it can never be null.

llvm-svn: 45695

llvm-svn: 45680

that "machine" classes are used to represent the current state of
the code being compiled.  Given this expanded name, we can start 
moving other stuff into it.  For now, move the UsedPhysRegs and
LiveIn/LoveOuts vectors from MachineFunction into it.

Update all the clients to match.

This also reduces some needless #includes, such as MachineModuleInfo
from MachineFunction.

llvm-svn: 45467

e.g. MO.isMBB() instead of MO.isMachineBasicBlock().  I don't plan on 
switching everything over, so new clients should just start using the 
shorter names.

Remove old long accessors, switching everything over to use the short
accessor: getMachineBasicBlock() -> getMBB(), 
getConstantPoolIndex() -> getIndex(), setMachineBasicBlock -> setMBB(), etc.

llvm-svn: 45464

  - Eliminate the static "print" method for operands, moving it
    into MachineOperand::print.
  - Change various set* methods for register flags to take a bool
    for the value to set it to.  Remove unset* methods.
  - Group methods more logically by operand flavor in MachineOperand.h

llvm-svn: 45461

llvm-svn: 45432

llvm-svn: 45418

When a live interval is being spilled, rather than creating short, non-spillable
intervals for every def / use, split the interval at BB boundaries. That is, for
every BB where the live interval is defined or used, create a new interval that
covers all the defs and uses in the BB.

This is designed to eliminate one common problem: multiple reloads of the same
value in a single basic block. Note, it does *not* decrease the number of spills
since no copies are inserted so the split intervals are *connected* through
spill and reloads (or rematerialization). The newly created intervals can be
spilled again, in that case, since it does not span multiple basic blocks, it's
spilled in the usual manner. However, it can reuse the same stack slot as the
previously split interval.

This is currently controlled by -split-intervals-at-bb.

llvm-svn: 44198

llvm-svn: 43866

defined on the same instruction. This fixes PR1767.

llvm-svn: 43699

isRegister, isImmediate, and isMachineBasicBlock, which are equivalent,
and more popular.

llvm-svn: 41958

llvm-svn: 41893

same time. Do not mark the "smaller" def as dead.

llvm-svn: 41871

llvm-svn: 40688

when there are no uses. This fixes a dangling-pointer bug, where pointers to
deleted instructions were not removed from kills lists. More info here:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2007-July/009749.html

llvm-svn: 40131

llvm-svn: 39979

llvm-svn: 37746

Properly handle kills of a physical register which has sub-registers that are read by later instructions.

llvm-svn: 37739

When marking a register as being implicitly defined, make sure to clear its partial use info as well.

llvm-svn: 37046

llvm-svn: 36943

llvm-svn: 36662

Due to darwin gcc bug, one version of darwin linker coalesces
static const int, which defauts PassID based pass identification.

llvm-svn: 36652