Commit Graph

120 Commits

Author SHA1 Message Date
David Blaikie
6d9dbd5526 Debug Info: Simplify Frame Index handling in DBG_VALUE Machine Instructions
Rather than using the full power of target-specific addressing modes in
DBG_VALUEs with Frame Indicies, simply use Frame Index + Offset. This
reduces the complexity of debug info handling down to two
representations of values (reg+offset and frame index+offset) rather
than three or four.

Ideally we could ensure that frame indicies had been eliminated by the
time we reached an assembly or dwarf generation, but I haven't spent the
time to figure out where the FIs are leaking through into that & whether
there's a good place to convert them. Some FI+offset=>reg+offset
conversion is done (see PrologEpilogInserter, for example) which is
necessary for some SelectionDAG assumptions about registers, I believe,
but it might be possible to make this a more thorough conversion &
ensure there are no remaining FIs no matter how instruction selection
is performed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184066 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-16 20:34:15 +00:00
Adrian Prantl
86a87d9ba1 Temporarily revert "Change the informal convention of DBG_VALUE so that we can express a"
because it breaks some buildbots.

This reverts commit 180816.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180819 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-30 22:35:14 +00:00
Adrian Prantl
a2b56692c8 Change the informal convention of DBG_VALUE so that we can express a
register-indirect address with an offset of 0.
It used to be that a DBG_VALUE is a register-indirect value if the offset
(operand 1) is nonzero. The new convention is that a DBG_VALUE is
register-indirect if the first operand is a register and the second
operand is an immediate. For plain registers use the combination reg, reg.

rdar://problem/13658587

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180816 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-30 22:16:46 +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
Jakob Stoklund Olesen
7f6ece8a93 Use MachineInstrBuilder in InstrEmitter.
This is supposed to be a mechanical change with no functional effects.

InstrEmitter can generate all types of MachineOperands which revealed
that MachineInstrBuilder was missing a few methods, added by this patch.

Besides providing a context pointer to MI::addOperand(),
MachineInstrBuilder seems like a better fit for this code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170712 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 18:08:09 +00:00
Patrik Hagglund
a61b17c18a Change TargetLowering::getRegClassFor to take an MVT, instead of EVT.
Accordingly, add helper funtions getSimpleValueType (in parallel to
getValueType) in SDValue, SDNode, and TargetLowering.

This is the first, in a series of patches.

This is the second attempt. In the first attempt (r169837), a few
getSimpleVT() were hoisted too far, detected by bootstrap failures.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170104 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-13 06:34:11 +00:00
Patrik Hagglund
34525f9ac0 Revert EVT->MVT changes, r169836-169851, due to buildbot failures.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169854 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-11 11:14:33 +00:00
Patrik Hagglund
8163ca76f0 Change TargetLowering::getRegClassFor to take an MVT, instead of EVT.
Accordingly, add helper funtions getSimpleValueType (in parallel to
getValueType) in SDValue, SDNode, and TargetLowering.

This is the first, in a series of patches.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169837 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-11 09:10:33 +00:00
Chandler Carruth
d04a8d4b33 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 16:50:05 +00:00
Chad Rosier
daeec8fad3 [inline asm] Get the mayLoad/mayStore directly from the MIOp_ExtraInfo operand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167050 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-30 20:39:19 +00:00
Chad Rosier
3d71688476 [inline asm] Implement mayLoad and mayStore for inline assembly. In general,
the MachineInstr MayLoad/MayLoad flags are based on the tablegen implementation.
For inline assembly, however, we need to compute these based on the constraints.

Revert r166929 as this is no longer needed, but leave the test case in place. 
rdar://12033048 and PR13504

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167040 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-30 19:11:54 +00:00
Micah Villmow
3574eca1b0 Move TargetData to DataLayout.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165402 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-08 16:38:25 +00:00
Michael Liao
6c7ccaa3fd Fix PR11985
- BlockAddress has no support of BA + offset form and there is no way to
  propagate that offset into machine operand;
- Add BA + offset support and a new interface 'getTargetBlockAddress' to
  simplify target block address forming;
- All targets are modified to use new interface and X86 backend is enhanced to
  support BA + offset addressing.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-12 21:43:09 +00:00
Owen Anderson
045ca86bb3 Remove an overly-aggressive assertion. The code following this assertion already knows how to handle the case where DstRC was NULL, so it's not actually protecting us from anything, and this pattern can come up when using unknown_class operands in the SelectionDAG.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163736 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-12 20:09:19 +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
94083149fd Add MachineInstr::tieOperands, remove setIsTied().
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163021 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-31 20:50:53 +00:00
Jakob Stoklund Olesen
908c0c01f6 Don't enforce ordered inline asm operands.
I was too optimistic, inline asm can have tied operands that don't
follow the def order.

Fixes PR13742.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162998 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-31 15:34:59 +00:00
Jakob Stoklund Olesen
492d76b02e Verify the order of tied operands in inline asm.
When there are multiple tied use-def pairs on an inline asm instruction,
the tied uses must appear in the same order as the defs.

It is possible to write an LLVM IR inline asm instruction that breaks
this constraint, but there is no reason for a front end to emit the
operands out of order.

The gnu inline asm syntax specifies tied operands as a single read/write
constraint "+r", so ouf of order operands are not possible.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162878 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-29 23:52:52 +00:00
Jakob Stoklund Olesen
66390805ad Set the isTied flags when building INLINEASM MachineInstrs.
For normal instructions, isTied() is set automatically by addOperand(),
based on MCInstrDesc, but inline asm has tied operands outside the
descriptor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162869 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-29 22:02:00 +00:00
Jakob Stoklund Olesen
baa74e4b35 Avoid including explicit uses when counting SDNode imp-uses.
It is legal to have a register node as an explicit operand, it shouldn't
be counted as an implicit use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162591 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-24 20:52:42 +00:00
Jakob Stoklund Olesen
74500bdba3 Add SelectionDAG::getTargetIndex.
This adds support for TargetIndex operands during isel. The meaning of
these (index, offset, flags) operands is entirely defined by the target.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161453 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-07 22:37:05 +00:00
Evan Cheng
875913439c InstrEmitter::EmitSubregNode() optimize extract_subreg in this case:
r1025 = s/zext r1024, 4
r1026 = extract_subreg r1025, 4

to a copy:
r1026 = copy r1024

This is correct. However it uses TII->isCoalescableExtInstr() which can return
true for instructions which essentially does a sext_in_reg so this can end up
with an illegal copy where the source and destination register classes do not
match. Add a check to avoid it. Sorry, no test case possible at this time.

rdar://11849816


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160059 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-11 18:55:07 +00:00
Jakob Stoklund Olesen
33a537a5c4 Allow trailing physreg RegisterSDNode operands on non-variadic instructions.
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159727 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-04 23:53:23 +00:00
Jakob Stoklund Olesen
8ccaad526a Clear kill flags in InstrEmitter::EmitSubregNode().
When a local virtual register is made global, make sure to clear any
existing kill flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159461 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-29 21:00:03 +00:00
Jakob Stoklund Olesen
397fc4874e Add an MF argument to TRI::getPointerRegClass() and TII::getRegClass().
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!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156328 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-07 22:10:26 +00:00
Andrew Trick
f12f6dff97 Added TargetRegisterInfo::getAllocatableClass.
The ensures that virtual registers always belong to an allocatable class.
If your target attempts to create a vreg for an operand that has no
allocatable register subclass, you will crash quickly.

This ensures that targets define register classes as intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156046 91177308-0d34-0410-b5e6-96231b3b80d8
2012-05-03 01:14:37 +00:00
Hal Finkel
f77c03a859 Don't crash when a glue node contains an internal CopyToReg
This is necessary to support the existing ppc lowering code for indirect calls.
Fixes PR12071.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151373 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-24 17:53:59 +00:00
Jakob Stoklund Olesen
59cb77fb11 Handle all live physreg defs in the same place.
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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149708 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-03 20:43:35 +00:00
David Blaikie
4d6ccb5f68 More dead code removal (using -Wunreachable-code)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148578 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20 21:51:11 +00:00
Jakob Stoklund Olesen
9cf37e8b48 Add a RegisterMaskSDNode class.
This SelectionDAG node will be attached to call nodes by LowerCall(),
and eventually becomes a MO_RegisterMask MachineOperand on the
MachineInstr representing the call instruction.

LowerCall() will attach a register mask that depends on the calling
convention.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148436 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-18 23:52:12 +00:00
Pete Cooper
cd7f02bb43 Fix ISD::REG_SEQUENCE to accept physical registers and change TwoAddressInstructionPass to insert copies for any physical reg operands of the REG_SEQUENCE
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148377 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-18 04:16:16 +00:00
Evan Cheng
5a96b3dad2 Add bundle aware API for querying instruction properties and switch the code
generator to it. For non-bundle instructions, these behave exactly the same
as the MC layer API.

For properties like mayLoad / mayStore, look into the bundle and if any of the
bundled instructions has the property it would return true.
For properties like isPredicable, only return true if *all* of the bundled
instructions have the property.
For properties like canFoldAsLoad, isCompare, conservatively return false for
bundles.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146026 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07 07:15:52 +00:00
Jakob Stoklund Olesen
d2ed2d71c9 Simplify EXTRACT_SUBREG emission.
EXTRACT_SUBREG is emitted as %dst = COPY %src:sub, so there is no need to
constrain the %dst register class.  RegisterCoalescer will apply the
necessary constraints if it decides to eliminate the COPY.

The %src register class does need to be constrained to something with
the right sub-registers, though.  This is currently done manually with
COPY_TO_REGCLASS nodes.  They can possibly be removed after this patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141207 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 20:26:40 +00:00
Jakob Stoklund Olesen
2c3bef8a15 Simplify INSERT_SUBREG emission.
The register class created by INSERT_SUBREG and SUBREG_TO_REG must be
legal and support the SubIdx sub-registers.

The new getSubClassWithSubReg() hook can compute that.

This may create INSERT_SUBREG instructions defining a larger register
class than the sub-register being inserted.  That is OK,
RegisterCoalescer will constrain the register class as needed when it
eliminates the INSERT_SUBREG instructions.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141198 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-05 18:31:00 +00:00
Jakob Stoklund Olesen
e27e1ca3c9 Move getCommonSubClass() into TRI.
It will soon need the context.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140896 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-30 22:18:51 +00:00
Jakob Stoklund Olesen
08f5cdf5b3 Constrain register classes instead of emitting copies.
Sometimes register class constraints are trivial, like GR32->GR32_NOSP,
or GPR->rGPR.  Teach InstrEmitter to simply constrain the virtual
register instead of emitting a copy in these cases.

Normally, these copies are handled by the coalescer.  This saves some
coalescer work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140340 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-22 21:39:34 +00:00
Andrew Trick
3be654f808 Lower ARM adds/subs to add/sub after adding optional CPSR operand.
This is still a hack until we can teach tblgen to generate the
optional CPSR operand rather than an implicit CPSR def. But the
strangeness is now limited to the selection DAG. ADD/SUB MI's no
longer have implicit CPSR defs, nor do we allow flag setting variants
of these opcodes in machine code. There are several corner cases to
consider, and getting one wrong would previously lead to nasty
miscompilation. It's not the first time I've debugged one, so this
time I added enough verification to ensure it won't happen again.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140228 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-21 02:20:46 +00:00
Andrew Trick
83a8031336 Restore hasPostISelHook tblgen flag.
No functionality change. The hook makes it explicit which patterns
require "special" handling. i.e. it self-documents tblgen
deficiencies. I plan to add verification in ExpandISelPseudos and
Thumb2SizeReduce to catch any missing hasPostISelHooks. Otherwise it's
too fragile.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140160 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-20 18:22:31 +00:00
Andrew Trick
4815d56bb2 ARM isel bug fix for adds/subs operands.
Modified ARMISelLowering::AdjustInstrPostInstrSelection to handle the
full gamut of CPSR defs/uses including instructins whose "optional"
cc_out operand is not really optional. This allowed removal of the
hasPostISelHook to simplify the .td files and make the implementation
more robust.
Fixes rdar://10137436: sqlite3 miscompile


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140134 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-20 03:17:40 +00:00
Andrew Trick
3af7a67629 whitespace
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140133 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-20 03:06:13 +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
Chris Lattner
db125cfaf5 land David Blaikie's patch to de-constify Type, with a few tweaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135375 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 04:54:35 +00:00
Evan Cheng
e837dead3c - Rename TargetInstrDesc, TargetOperandInfo to MCInstrDesc and MCOperandInfo and
sink them into MC layer.
- Added MCInstrInfo, which captures the tablegen generated static data. Chang
TargetInstrInfo so it's based off MCInstrInfo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134021 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-28 19:10:37 +00:00
Evan Cheng
15993f83a4 More refactoring. Move getRegClass from TargetOperandInfo to TargetInstrInfo.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133944 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-27 21:26:13 +00:00
Jakob Stoklund Olesen
f792fa90f1 Distinguish early clobber output operands from clobbered registers.
Both become <earlyclobber> defs on the INLINEASM MachineInstr, but we
now use two different asm operand kinds.

The new Kind_Clobber is treated identically to the old
Kind_RegDefEarlyClobber for now, but x87 floating point stack inline
assembly does care about the difference.

This will pop a register off the stack:

  asm("fstp %st" : : "t"(x) : "st");

While this will pop the input and push an output:

  asm("fst %st" : "=&t"(r) : "t"(x));

We need to know if ST0 was a clobber or an output operand, and we can't
depend on <dead> flags for that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133902 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-27 04:08:33 +00:00
Devang Patel
8594d429e0 Handle debug info for i128 constants.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133821 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-24 20:46:11 +00:00
Jakob Stoklund Olesen
c02a6fa7d8 Don't use register classes larger than TLI->getRegClassFor(VT).
In Thumb mode we cannot handle GPR virtual registers, even though some
instructions can. When isel is lowering a CopyFromReg, it should limit
itself to subclasses of getRegClassFor(VT).

<rdar://problem/9624323>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133210 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-16 22:50:38 +00:00
Owen Anderson
1300f3019e Change the REG_SEQUENCE SDNode to take an explict register class ID as its first operand. This operand is lowered away by the time we reach MachineInstrs, so the actual register-allocation handling of them doesn't need to change.
This is intended to support using REG_SEQUENCE SDNode's with type MVT::untyped, and is part of the long road to eliminating some of the hacks we currently use to support register pairs and other strange constraints, particularly on ARM NEON.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133178 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-16 18:17:13 +00:00
Jakob Stoklund Olesen
fa226bccaa Use TRI::has{Sub,Super}ClassEq() where possible.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132455 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-02 05:43:46 +00:00
Jakob Stoklund Olesen
c9df025e33 Simplify a bunch of isVirtualRegister() and isPhysicalRegister() logic.
These functions not longer assert when passed 0, but simply return false instead.

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123155 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-10 02:58:51 +00:00