After much agonizing, use a full 4 bits of precious MachineOperand space
to encode this. This uses existing padding, and doesn't grow
MachineOperand beyond its current 32 bytes.

This allows tied defs among the first 15 operands on a normal
instruction, just like the current MCInstrDesc constraint encoding.
Inline assembly needs to be able to tie more than the first 15 operands,
and gets special treatment.

Tied uses can appear beyond 15 operands, as long as they are tied to a
def that's in range.

llvm-svn: 163151

Manage tied operands entirely internally to MachineInstr. This makes it
possible to change the representation of tied operands, as I will do
shortly.

The constraint that tied uses and defs must be in the same order was too
restrictive.

llvm-svn: 163021

When a MachineInstr is constructed, its implicit operands are added
first, then the explicit operands are inserted before the implicits.

MCInstrDesc has oprand flags like early clobber and operand ties that
apply to the explicit operands.

Don't look at those flags when the implicit operands are first added in
the explicit operands's positions.

llvm-svn: 162910

Ordered memory operations are more constrained than volatile loads and
stores because they must be ordered with respect to all other memory
operations.

llvm-svn: 162861

It is technically allowed to move a normal load across a volatile load,
but probably not a good idea.

It is not allowed to move a load across an atomic load with
Ordering > Monotonic, and we model those with MOVolatile as well.

I recently removed the mayStore flag from atomic load instructions, so
they don't need a pseudo-opcode. This patch makes up for the difference.

llvm-svn: 162857

The isTied bit is set automatically when a tied use is added and
MCInstrDesc indicates a tied operand. The tie is broken when one of the
tied operands is removed.

llvm-svn: 162814

While in SSA form, a MachineInstr can have pairs of tied defs and uses.
The tied operands are used to represent read-modify-write operands that
must be assigned the same physical register.

Previously, tied operand pairs were computed from fixed MCInstrDesc
fields, or by using black magic on inline assembly instructions.

The isTied flag makes it possible to add tied operands to any
instruction while getting rid of (some of) the inlineasm magic.

Tied operands on normal instructions are needed to represent predicated
individual instructions in SSA form. An extra <tied,imp-use> operand is
required to represent the output value when the instruction predicate is
false.

Adding a predicate to:

  %vreg0<def> = ADD %vreg1, %vreg2

Will look like:

  %vreg0<tied,def> = ADD %vreg1, %vreg2, pred:3, %vreg7<tied,imp-use>

The virtual register %vreg7 is the value given to %vreg0 when the
predicate is false. It will be assigned the same physreg as %vreg0.

This commit adds the isTied flag and sets it based on MCInstrDesc when
building an instruction. The flag is not used for anything yet.

llvm-svn: 162774

Register operands are manipulated by a lot of target-independent code,
and it is not always possible to preserve target flags. That means it is
not safe to use target flags on register operands.

None of the targets in the tree are using register operand target flags.
External targets should be using immediate operands to annotate
instructions with operand modifiers.

llvm-svn: 162770

This was the cause of the buildbot failures.

llvm-svn: 161643

Register MachineOperands are kept in linked lists accessible via MRI's
reg_iterator interfaces. The linked list management was handled partly
by MachineOperand methods, partly by MRI methods.

Move all of the list management into MRI, delete
MO::AddRegOperandToRegInfo() and MO::RemoveRegOperandFromRegInfo().

Be more explicit about handling the cases where an MRI pointer isn't
available.

llvm-svn: 161632

A target index operand looks a lot like a constant pool reference, but
it is completely target-defined. It contains the 8-bit TargetFlags, a
32-bit index, and a 64-bit offset. It is preserved by all code generator
passes.

TargetIndex operands can be used to carry target-specific information in
cases where immediate operands won't suffice.

llvm-svn: 161441

hash_value overload for MachineOperands. This addresses a FIXME
sufficient for me to remove it, and cleans up the code nicely too.

The important changes to the hashing logic:
- TargetFlags are now included in all of the hashes. These were complete
  missed.
- Register operands have their subregisters and whether they are a def
  included in the hash.
- We now actually hash all of the operand types. Previously, many
  operand types were simply *dropped on the floor*. For example:
  - Floating point immediates
  - Large integer immediates (>64-bit)
  - External globals!
  - Register masks
  - Metadata operands
- It removes the offset from the block-address hash; I'm a bit
  suspicious of this, but isIdenticalTo doesn't consider the offset for
  black addresses.

Any patterns involving these entities could have triggered extreme
slowdowns in MachineCSE or PHIElimination. Let me know if there are PRs
you think might be closed now... I'm looking myself, but I may miss
them.

llvm-svn: 159743

broken. This patch fixes the superficial problems which lead to the
intractably slow compile times reported in PR13225.

The specific issue is that we were failing to include the *offset* of
a global variable in the hash code. Oops. This would in turn cause all
MIs which were only distinguishable due to operating on different
offsets of a global variable to produce identical hash functions. In
some of the test cases attached to the PR I saw hash table activity
where there were O(1000) probes-per-lookup *on average*. A very few
entries were responsible for most of these probes.

There is still quite a bit more to do here. The ad-hoc layering of data
in MachineOperands makes them *extremely* brittle to hash correctly.
We're missing quite a few other cases, the only ones I've fixed here are
the specific MO types which were allowed through the assert() in
getOffset().

llvm-svn: 159741

Also allow trailing register mask operands on non-variadic both
MachineSDNodes and MachineInstrs.

The extra physreg RegisterSDNode operands are added to the MI as
<imp-use> operands. This makes it possible to have non-variadic call
instructions.

Call and return instructions really are non-variadic, the argument
registers should only be used implicitly - they are not part of the
encoding.

llvm-svn: 159727

include/llvm/Analysis/DebugInfo.h to include/llvm/DebugInfo.h.

The reasoning is because the DebugInfo module is simply an interface to the
debug info MDNodes and has nothing to do with analysis.

llvm-svn: 159312

Patch by Ivan Llopard.

llvm-svn: 158025

No functional change intended.

Sorry for the churn. The iterator classes are supposed to help avoid
giant commits like this one in the future. The TableGen-produced
register lists are getting quite large, and it may be necessary to
change the table representation.

This makes it possible to do so without changing all clients (again).

llvm-svn: 157854

An empty list is not represented as a null pointer. Let TRI do its own
shortcuts.

llvm-svn: 157702

The getPointerRegClass() hook can return register classes that depend on
the calling convention of the current function (ptr_rc_tailcall).

So far, we have been able to infer the calling convention from the
subtarget alone, but as we add support for multiple calling conventions
per target, that no longer works.

Patch by Yiannis Tsiouris!

llvm-svn: 156328

llvm-svn: 156219

The <undef> flag on a def operand only applies to partial register
redefinitions. Only print the flag when relevant, and print it as
<def,read-undef> to make it clearer what it means.

llvm-svn: 155239

This is the CodeGen equivalent of r153747. I tested that there is not noticeable
performance difference with any combination of -O0/-O2 /-g when compiling
gcc as a single compilation unit.

llvm-svn: 153817

This is particularly helpful as both arguments tend to be constants.

llvm-svn: 152991

Saves one machine word on MachineInstr (88->80 bytes on x86_64, 48->44 on i386).

llvm-svn: 152930

llvm-svn: 152301

llvm-svn: 152221

This one is particularly annoying because the hashing algorithm is
highly specialized, with a strange "equivalence" definition that subsets
the fields involved.

Still, this looks at the exact same set of data as the old code, but
without bitwise or-ing over parts of it and other mixing badness. No
functionality changed here. I've left a substantial fixme about the fact
that there is a cleaner and more principled way to do this, but it
requires making the equality definition actual stable for particular
types...

llvm-svn: 152218

llvm-svn: 152001

This allows the function to be inlined, and makes it suitable for use in
getInstructionIndex().

Also provide a const version. C++ is great for touch typing practice.

llvm-svn: 151782

llvm-svn: 150778

llvm-svn: 150630

Only accept register masks when looking for an 'overlapping' def. When
Overlap is not set, the function searches for a proper definition of
Reg.

This means MI->modifiesRegister() considers register masks, but
MI->definesRegister() doesn't.

llvm-svn: 150529

Put instruction names into an indexed string table on the side, removing a pointer from MCInstrDesc.

Make them accessible through MCInstrInfo. They are only used for debugging purposes so this doesn't
have an impact on performance. X86MCTargetDesc.o goes from 630K to 461K on x86_64.

llvm-svn: 150245

llvm-svn: 150044

Calls that use register mask operands don't have implicit defs for
returned values.  The register mask operand handles the call clobber,
but it always behaves like a set of dead defs.

Add live implicit defs for any implicitly defined physregs that are
actually used.

llvm-svn: 149715

llvm-svn: 149709

SelectionDAG has 4 different ways of passing physreg defs to users.
Collect all of the uses at the same time, and pass all of them to
MI->setPhysRegsDeadExcept() to mark the remaining defs dead.

The setPhysRegsDeadExcept() function will soon add the required
implicit-defs to instructions with register mask operands.

llvm-svn: 149708

It doesn't seem worthwhile to give meaning to a NULL register mask
pointer. It complicates all the code using register mask operands.

llvm-svn: 149646

The live range of the source register may be extended when a redundant
copy is eliminated. Make sure any kill flags between the two copies are
cleared.

This fixes PR11765.

llvm-svn: 149069

Register masks will be used as a compact representation of large clobber
lists.  Currently, an x86 call instruction has some 40 operands
representing call-clobbered registers.  That's more than 1kB of useless
operands per call site.

A register mask operand references a bit mask of call-preserved
registers, everything else is clobbered.  The bit mask will typically
come from TargetRegisterInfo::getCallPreservedMask().

By abandoning ImplicitDefs for call-clobbered registers, it also becomes
possible to share call instruction descriptions between calling
conventions, and we can get rid of the WINCALL* instructions.

This patch introduces the new operand kind.  Future patches will add
RegMask support to target-independent passes before finally the fixed
clobber lists can be removed from call instruction descriptions.

llvm-svn: 148250