Commit Graph

131 Commits

Author SHA1 Message Date
Chad Rosier
88eb89b89f [asm parser] Add support for predicating MnemonicAlias based on the assembler
variant/dialect.  Addresses a FIXME in the emitMnemonicAliases function.
Use and test case to come shortly.
rdar://13688439 and part of PR13340.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179804 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-18 22:35:36 +00:00
Chad Rosier
05862c9788 Fix comment spacing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179761 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-18 15:19:45 +00:00
Jakob Stoklund Olesen
64110ffc9e Add SchedRW as an Instruction field.
Don't require instructions to inherit Sched<...>. Sometimes it is more
convenient to say:

  let SchedRW = ... in {
    ...
  }

Which is now possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@177199 91177308-0d34-0410-b5e6-96231b3b80d8
2013-03-15 22:51:13 +00:00
Tim Northover
ff9d058f28 Add deprecation of neverHasSideEffects to documentation comments.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175175 91177308-0d34-0410-b5e6-96231b3b80d8
2013-02-14 16:31:06 +00:00
Chandler Carruth
0b8c9a80f2 Move all of the header files which are involved in modelling the LLVM IR
into their new header subdirectory: include/llvm/IR. This matches the
directory structure of lib, and begins to correct a long standing point
of file layout clutter in LLVM.

There are still more header files to move here, but I wanted to handle
them in separate commits to make tracking what files make sense at each
layer easier.

The only really questionable files here are the target intrinsic
tablegen files. But that's a battle I'd rather not fight today.

I've updated both CMake and Makefile build systems (I think, and my
tests think, but I may have missed something).

I've also re-sorted the includes throughout the project. I'll be
committing updates to Clang, DragonEgg, and Polly momentarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171366 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-02 11:36:10 +00:00
Sebastian Pop
becdf4d7cd add TableGen support to create relationship maps between instructions
Relationship maps are represented as InstrMapping records which are parsed by
TableGen and the information is used to construct mapping tables to represent
appropriate relations between instructions. These tables are emitted into
XXXGenInstrInfo.inc file along with the functions to query them.

Patch by Jyotsna Verma <jverma@codeaurora.org>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166685 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-25 15:54:06 +00:00
Andrew Trick
1008f8c789 comment
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163876 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-14 06:18:52 +00:00
Owen Anderson
83c0eefa3b Improve tblgen code cleanliness: create an unknown_class, from which the unknown def inherits. Make tblgen check for that class, rather than checking for the def itself.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163664 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-11 23:47:08 +00:00
Tom Stellard
6d3d765653 Tablegen: Add OperandWithDefaultOps Operand type
This Operand type takes a default argument, and is initialized to
this value if it does not appear in a patter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163315 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:15:52 +00:00
Nadav Rotem
c05d30601c Add a new optimization pass: Stack Coloring, that merges disjoint static allocations (allocas). Allocas are known to be
disjoint if they are marked by disjoint lifetime markers (@llvm.lifetime.XXX intrinsics).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163299 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 09:17:37 +00:00
Jakob Stoklund Olesen
c1f10fd5b9 Tristate mayLoad, mayStore, and hasSideEffects.
Keep track of the set/unset state of these bits along with their
true/false values, but treat '?' as '0' for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162461 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-23 19:34:46 +00:00
Jakob Stoklund Olesen
f104bf65b9 Add CodeGenTarget::guessInstructionProperties.
Currently, TableGen just guesses instruction properties when it can't
infer them form patterns.

This adds a guessInstructionProperties flag to the instruction set
definition that will be used to disable guessing. The flag is intended
as a migration aid. It will be removed again when no more targets need
their properties guessed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162460 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-23 19:34:41 +00:00
Akira Hatanaka
72e9b6aeb4 Add stub methods for mips assembly matcher.
Patch by Vladimir Medic.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162124 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-17 20:16:42 +00:00
Jakob Stoklund Olesen
f2c64ef519 Add an MCID::Select flag and TII hooks for optimizing selects.
Select instructions pick one of two virtual registers based on a
condition, like x86 cmov. On targets like ARM that support predication,
selects can sometimes be eliminated by predicating the instruction
defining one of the operands.

Teach PeepholeOptimizer to recognize select instructions, and ask the
target to optimize them.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162059 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-16 23:11:47 +00:00
Jakob Stoklund Olesen
d024a20bf7 Add a CoveringSubRegIndices field to SubRegIndex records.
This can be used to tell TableGen to use a specific SubRegIndex instead
of synthesizing one when discovering all sub-registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161982 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-15 20:15:48 +00:00
Jakob Stoklund Olesen
2ca6b3c374 Remove support for 'CompositeIndices' and sub-register cycles.
Now that the weird X86 sub_ss and sub_sd sub-register indexes are gone,
there is no longer a need for the CompositeIndices construct in .td
files. Sub-register index composition can be specified on the
SubRegIndex itself using the ComposedOf field.

Also enforce unique names for sub-registers in TableGen. The same
sub-register cannot be available with multiple sub-register indexes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160842 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-26 23:39:50 +00:00
Owen Anderson
0fcaaafd1a Make RegisterOperand a subclass of DAGOperand so that RegisterOperands can be passed into multiclasses that take DAGOperands as multiclass parameters.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160540 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-20 03:38:19 +00:00
Andrew Trick
2661b411cc I'm introducing a new machine model to simultaneously allow simple
subtarget CPU descriptions and support new features of
MachineScheduler.

MachineModel has three categories of data:
1) Basic properties for coarse grained instruction cost model.
2) Scheduler Read/Write resources for simple per-opcode and operand cost model (TBD).
3) Instruction itineraties for detailed per-cycle reservation tables.

These will all live side-by-side. Any subtarget can use any
combination of them. Instruction itineraries will not change in the
near term. In the long run, I expect them to only be relevant for
in-order VLIW machines that have complex contraints and require a
precise scheduling/bundling model. Once itineraries are only actively
used by VLIW-ish targets, they could be replaced by something more
appropriate for those targets.

This tablegen backend rewrite sets things up for introducing
MachineModel type #2: per opcode/operand cost model.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159891 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-07 04:00:00 +00:00
Andrew Trick
06495cd7f2 whitespace
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159890 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-07 03:59:51 +00:00
Owen Anderson
2c5fbb9bcb Define DAGOperand, an empty base class for RegisterClass and Operand. This allows one to write multiclasses that are polymorphic over both registers and non-register operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159162 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-25 21:25:16 +00:00
Jim Grosbach
4dbfdfba6c TableGen: AsmMatcher support for better operand diagnostics.
"Invalid operand" may be a completely correct diagnostic, but it's often
insufficiently specific to really help identify and fix the problem in
assembly source. Allow a target to specify a more-specific diagnostic kind
for each AsmOperandClass derived definition and use that to provide
more detailed diagnostics when an operant of that class resulted in a
match failure.

rdar://8987109

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159050 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-22 23:56:44 +00:00
Owen Anderson
6b31d4ea36 Teach tblgen's set theory "sequence" operator to support an optional stride operand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157416 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-24 21:37:08 +00:00
Jim Grosbach
0ee07e0130 TableGen'erate mapping physical registers to encoding values.
Many targets always use the same bitwise encoding value for physical
registers in all (or most) instructions. Add this mapping to the
.td files and TableGen'erate the information and expose an accessor
in MCRegisterInfo.

patch by Tom Stellard.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156829 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-15 17:35:57 +00:00
Jakob Stoklund Olesen
338607ae0d Remove the SubRegClasses field from RegisterClass descriptions.
This information in now computed by TableGen.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156152 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-04 03:30:34 +00:00
Jim Grosbach
14ce6fac24 ARM: improved assembler diagnostics for missing CPU features.
When an instruction match is found, but the subtarget features it
requires are not available (missing floating point unit, or thumb vs arm
mode, for example), issue a diagnostic that identifies what the feature
mismatch is.

rdar://11257547

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155499 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-24 22:40:08 +00:00
Jim Grosbach
2efd8acb3c Add documentation comment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155203 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-20 16:29:46 +00:00
Jim Grosbach
c1922c72ad TableGen support for auto-generating assembly two-operand aliases.
Assembly matchers for instructions with a two-operand form. ARM is full
of these, for example:
  add {Rd}, Rn, Rm  // Rd is optional and is the same as Rn if omitted.

The property TwoOperandAliasConstraint on the instruction definition controls
when, and if, an alias will be formed. No explicit InstAlias definitions
are required.

rdar://11255754

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155172 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-19 23:59:23 +00:00
Jakob Stoklund Olesen
b5af2d943e Specify SubRegIndex components on the index itself.
It is simpler to define a composite index directly:

  def ssub_2 : SubRegIndex<[dsub_1, ssub_0]>;
  def ssub_3 : SubRegIndex<[dsub_1, ssub_1]>;

Than specifying the composite indices on each register:

  CompositeIndices = [(ssub_2 dsub_1, ssub_0),
                      (ssub_3 dsub_1, ssub_1)] in ...

This also makes it clear that SubRegIndex composition is supposed to be
unique.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149556 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-01 23:16:41 +00:00
Jakob Stoklund Olesen
5b52f6d655 Add an (interleave A, B, ...) SetTheory operator.
This will interleave the elements from two or more lists.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148824 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-24 18:06:05 +00:00
Jakob Stoklund Olesen
31867660cb Add a CoveredBySubRegs property to Register descriptions.
When set, this bit indicates that a register is completely defined by
the value of its sub-registers.

Use the CoveredBySubRegs property to infer which super-registers are
call-preserved given a list of callee-saved registers.  For example, the
ARM registers D8-D15 are callee-saved.  This now automatically implies
that Q4-Q7 are call-preserved.

Conversely, Win64 callees save XMM6-XMM15, but the corresponding
YMM6-YMM15 registers are not call-preserved because they are not fully
defined by their sub-registers.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148363 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-18 00:16:39 +00:00
Devang Patel
0dbcadaa2f Split AsmParser into two components - AsmParser and AsmParserVariant
AsmParser holds info specific to target parser.
AsmParserVariant holds info specific to asm variants supported by the target.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147787 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-09 19:13:28 +00:00
Jim Grosbach
a66512e591 Extend AsmMatcher token literal matching to allow aliasing.
For example, ARM allows:
    vmov.u32 s4, #0  -> vmov.i32, #0
'u32' is a more specific designator for the 32-bit integer type specifier
and is legal for any instruction which accepts 'i32' as a datatype suffix.

We want to say,
    def : TokenAlias<".u32", ".i32">;

This works by marking the match class of 'From' as a subclass of the
match class of 'To'.

rdar://10435076



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145992 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-06 23:43:54 +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
Nick Lewycky
8a8d479214 Move global variables in TargetMachine into new TargetOptions class. As an API
change, now you need a TargetOptions object to create a TargetMachine. Clang
patch to follow.

One small functionality change in PTX. PTX had commented out the machine
verifier parts in their copy of printAndVerify. That now calls the version in
LLVMTargetMachine. Users of PTX who need verification disabled should rely on
not passing the command-line flag to enable it.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145714 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-02 22:16:29 +00:00
Andrew Trick
90b7b12f01 Use ARM/t2PseudoInst class from ARM/Thumb2 special adds/subs patterns.
Clean up the patterns, fix comments, and avoid confusing both tools
and coders. Note that the special adds/subs SelectionDAG nodes no
longer have the dummy cc_out operand.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142397 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-18 19:18:52 +00:00
Andrew Trick
7f5f0dae33 whitespace
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@142394 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-18 18:40:53 +00:00
Jakob Stoklund Olesen
5a57168a55 Mark the standard pseudos as isPseudo = 1.
The difference between isPseudo and isCodeGenOnly is a bit murky, but
isCodeGenOnly should eventually go away.  It is used for instructions
that are clones of real instructions with slightly different properties.

The standard pseudo-instructions never mirror real instructions, so they
are definitely in the isPseudo category.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141567 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-10 18:51:33 +00:00
Evan Cheng
37fefc20d3 Follow up to r138791.
Add a instruction flag: hasPostISelHook which tells the pre-RA scheduler to
call a target hook to adjust the instruction. For ARM, this is used to
adjust instructions which may be setting the 's' flag. ADC, SBC, RSB, and RSC
instructions have implicit def of CPSR (required since it now uses CPSR physical
register dependency rather than "glue"). If the carry flag is used, then the
target hook will *fill in* the optional operand with CPSR. Otherwise, the hook
will remove the CPSR implicit def from the MachineInstr.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138810 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-30 19:09:48 +00:00
Owen Anderson
f1a0090073 Enhance the FixedLengthDecoder to be able to generate plausible-looking decoders for ARM.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135524 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-19 21:06:00 +00:00
Benjamin Kramer
5196c12e9f Add a new field to MCOperandInfo that contains information about the type of the Operand.
- The actual values are from the MCOI::OperandType enum.
- Teach tblgen to read it from the instruction definition.
- This is a better implementation of the hacks in edis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135197 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-14 21:47:18 +00:00
Owen Anderson
16884415db Add a target-indepedent entry to MCInstrDesc to describe the encoded size of an opcode. Switch ARM over to using that rather than its own special MCInstrDesc bits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135106 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-13 23:22:26 +00:00
Jim Grosbach
86f9adb8be TableGen'erated MC lowering for simple pseudo-instructions.
This allows the (many) pseudo-instructions we have that map onto a single
real instruction to have their expansion during MC lowering handled
automatically instead of the current cumbersome manual expansion required.
These sorts of pseudos are common when an instruction is used in situations
that require different MachineInstr flags (isTerminator, isBranch, et. al.)
than the generic instruction description has. For example, using a move
to the PC to implement a branch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134704 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-08 17:36:35 +00:00
Evan Cheng
ebdeeab812 Eliminate asm parser's dependency on TargetMachine:
- Each target asm parser now creates its own MCSubtatgetInfo (if needed).
- Changed AssemblerPredicate to take subtarget features which tablegen uses
  to generate asm matcher subtarget feature queries. e.g.
  "ModeThumb,FeatureThumb2" is translated to
  "(Bits & ModeThumb) != 0 && (Bits & FeatureThumb2) != 0".


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134678 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-08 01:53:10 +00:00
Jim Grosbach
806fcc040e Don't require pseudo-instructions to carry encoding information.
For now this is distinct from isCodeGenOnly, as code-gen-only
instructions can (and often do) still have encoding information
associated with them. Once we've migrated all of them over to true
pseudo-instructions that are lowered to real instructions prior to
the printer/emitter, we can remove isCodeGenOnly and just use isPseudo.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134539 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-06 21:33:38 +00:00
Owen Anderson
bea6f615ee Add support for alternative register names, useful for instructions whose operands are logically equivalent to existing registers, but happen to be printed specially. For example, an instruciton that prints d0[0] instead of s0.
Patch by Jim Grosbach.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133940 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-27 21:06:21 +00:00
Jakob Stoklund Olesen
4ce25d5d69 Add a RegisterTuples class to Target.td and TableGen.
A RegisterTuples instance is used to synthesize super-registers by
zipping together lists of sub-registers. This is useful for generating
pseudo-registers representing register sequence constraints like 'two
consecutive GPRs', or 'an even-odd pair of floating point registers'.

The RegisterTuples def can be used in register set operations when
building register classes. That is the only way of accessing the
synthesized super-registers.

For example, the ARM QQ register class of pseudo-registers could have
been formed like this:

  // Form pairs Q0_Q1, Q2_Q3, ...
  def QQPairs : RegisterTuples<[qsub_0, qsub_1],
                               [(decimate QPR, 2),
                                (decimate (shl QPR, 1), 2)]>;

  def QQ : RegisterClass<..., (add QQPairs)>;

Similarly, pseudo-registers representing '3 consecutive D-regs with
wraparound' look like:

  // Form D0_D1_D2, D1_D2_D3, ..., D30_D31_D0, D31_D0_D1.
  def DSeqTriples : RegisterTuples<[dsub_0, dsub_1, dsub_2],
                                   [(rotl DPR, 0),
                                    (rotl DPR, 1),
                                    (rotl DPR, 2)]>;

TableGen automatically computes aliasing information for the synthesized
registers.

Register tuples are still somewhat experimental. We still need to see
how they interact with MC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133407 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-20 02:50:54 +00:00
Jakob Stoklund Olesen
54c47c1ce9 Remove MethodProtos/MethodBodies and allocation_order_begin/end.
Targets that need to change the default allocation order should use the
AltOrders mechanism instead. See the X86 and ARM targets for examples.

The allocation_order_begin() and allocation_order_end() methods have been
replaced with getRawAllocationOrder(), and there is further support
functions in RegisterClassInfo.

It is no longer possible to insert arbitrary code into generated
register classes. This is a feature.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133332 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-18 03:08:20 +00:00
Jakob Stoklund Olesen
b4c704877d Provide AltOrders for specifying alternative allocation orders.
A register class can define AltOrders and AltOrderSelect instead of
defining method protos and bodies. The AltOrders lists can be defined
with set operations, and TableGen can verify that the alternative
allocation orders only contain valid registers.

This is currently an opt-in feature, and it is still possible to
override allocation_order_begin/end. That will not be true for long.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133320 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-18 00:50:49 +00:00
Jakob Stoklund Olesen
f28987b76e Use set operations instead of plain lists to enumerate register classes.
This simplifies many of the target description files since it is common
for register classes to be related or contain sequences of numbered
registers.

I have verified that this doesn't change the files generated by TableGen
for ARM and X86. It alters the allocation order of MBlaze GPR and Mips
FGR32 registers, but I believe the change is benign.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133105 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-15 23:28:14 +00:00
Jakob Stoklund Olesen
f462e3fac7 Make it possible to have unallocatable register classes.
Some register classes are only used for instruction operand constraints.
They should never be used for virtual registers. Previously, those
register classes were given an empty allocation order, but now you can
say 'let isAllocatable=0' in the register class definition.

TableGen calculates if a register is part of any allocatable register
class, and makes that information available in TargetRegisterDesc::inAllocatableClass.

The goal here is to eliminate use cases for overriding allocation_order_*
methods.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132508 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-02 23:07:20 +00:00