Commit Graph

102985 Commits

Author SHA1 Message Date
Andrea Di Biagio
96db9b8ed8 [InstCombine][X86] Teach how to fold calls to SSE2/AVX2 packed logical shift
right intrinsics.

A packed logical shift right with a shift count bigger than or equal to the
element size always produces a zero vector. In all other cases, it can be
safely replaced by a 'lshr' instruction.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207299 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-26 01:03:22 +00:00
Richard Smith
f3a9eb107c Add missing include guards and missing #include, found by modules build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207298 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-26 00:53:26 +00:00
Filipe Cabecinhas
31e75e673c Appease the almighty buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207295 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-26 00:02:37 +00:00
Filipe Cabecinhas
3c02165172 Optimization for certain shufflevector by using insertps.
Summary:
If we're doing a v4f32/v4i32 shuffle on x86 with SSE4.1, we can lower
certain shufflevectors to an insertps instruction:
When most of the shufflevector result's elements come from one vector (and
keep their index), and one element comes from another vector or a memory
operand.

Added tests for insertps optimizations on shufflevector.
Added support and tests for v4i32 vector optimization.

Reviewers: nadav

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D3475

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207291 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 23:51:17 +00:00
Duncan P. N. Exon Smith
cee7abfb2c Revert "blockfreq: Approximate irreducible control flow"
This reverts commit r207286.  It causes an ICE on the
cmake-llvm-x86_64-linux buildbot [1]:

    llvm/lib/Analysis/BlockFrequencyInfo.cpp: In lambda function:
    llvm/lib/Analysis/BlockFrequencyInfo.cpp:182:1: internal compiler error: in get_expr_operands, at tree-ssa-operands.c:1035

[1]: http://bb.pgr.jp/builders/cmake-llvm-x86_64-linux/builds/12093/steps/build_llvm/logs/stdio

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207287 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 23:16:58 +00:00
Duncan P. N. Exon Smith
d905bba691 blockfreq: Approximate irreducible control flow
Previously, irreducible backedges were ignored.  With this commit,
irreducible SCCs are discovered on the fly, and modelled as loops with
multiple headers.

This approximation specifies the headers of irreducible sub-SCCs as its
entry blocks and all nodes that are targets of a backedge within it
(excluding backedges within true sub-loops).  Block frequency
calculations act as if we insert a new block that intercepts all the
edges to the headers.  All backedges and entries to the irreducible SCC
point to this imaginary block.  This imaginary block has an edge (with
even probability) to each header block.

The result is now reasonable enough that I've added a number of
testcases for irreducible control flow.  I've outlined in
`BlockFrequencyInfoImpl.h` ways to improve the approximation.

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207286 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 23:08:57 +00:00
Adrian Prantl
2bfbbd5d4d Unbreak the gdb buildbot by not lowering dbg.declare intrinsics for arrays.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207284 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 23:00:25 +00:00
Eric Christopher
eed2620611 Make sure that rangelists are also relative to the compile unit
low_pc similar to location lists.

Fixes PR19563

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207283 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 22:23:54 +00:00
Matt Arsenault
d1f361aa39 R600: Fix function name printing in LowerCall
v2: Check both ExternalSymbol and GlobalAddress

Patch by: Jan Vesely <jan.vesely@rutgers.edu>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207282 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 22:22:01 +00:00
David Blaikie
82a35bf01a DwarfAccelTable: Store the string symbol in the accelerator table to avoid duplicate lookup.
This also avoids the need for subtly side-effecting calls to manifest
strings in the string table at the point where items are added to the
accelerator tables.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207281 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 22:21:35 +00:00
Tom Roeder
817f5e2fa1 Add an -mattr option to the gold plugin to support subtarget features in LTO
This adds support for an -mattr option to the gold plugin and to llvm-lto. This
allows the caller to specify details of the subtarget architecture, like +aes,
or +ssse3 on x86.  Note that this requires a change to the include/llvm-c/lto.h
interface: it adds a function lto_codegen_set_attr and it increments the
version of the interface.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207279 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 21:46:51 +00:00
Alexey Samsonov
c744a37153 Fix missing include
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207278 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 21:42:35 +00:00
David Blaikie
891481f89d Encapsulate the DWARF string pool in a separate type.
Pulls out some more code from some of the rather monolithic DWARF
classes. Unlike the address table, the string table won't move up into
DwarfDebug - each DWARF file has its own string table (but there can be
only one address table).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207277 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 21:34:35 +00:00
Alexey Samsonov
c87722ce4b [DWARF parser] Cleanup code in DWARFDebugAranges.
No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207276 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 21:30:03 +00:00
Alexey Samsonov
bfd66f57da [DWARF parser] Cleanup code in DWARFDebugAbbrev.
No functionality change.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207274 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 21:10:56 +00:00
Adam Nemet
d761cc1dfa [LoopStrengthReduce] Don't trim formula that uses a subset of required registers
Consider this use from the new testcase:

  LSR Use: Kind=ICmpZero, Offsets={0}, widest fixup type: i32
    reg({1000,+,-1}<nw><%for.body>)
    -3003 + reg({3,+,3}<nw><%for.body>)
    -1001 + reg({1,+,1}<nuw><nsw><%for.body>)
    -1000 + reg({0,+,1}<nw><%for.body>)
    -3000 + reg({0,+,3}<nuw><%for.body>)
    reg({-1000,+,1}<nw><%for.body>)
    reg({-3000,+,3}<nsw><%for.body>)

This is the last use we consider for a solution in SolveRecurse, so CurRegs is
a large set.  (CurRegs is the set of registers that are needed by the
previously visited uses in the in-progress solution.)

ReqRegs is {
  {3,+,3}<nw><%for.body>,
  {1,+,1}<nuw><nsw><%for.body>
}

This is the intersection of the regs used by any of the formulas for the
current use and CurRegs.

Now, the code requires a formula to contain *all* these regs (the comment is
simply wrong), otherwise the formula is immediately disqualified.  Obviously,
no formula for this use contains two regs so they will all get disqualified.

The fix modifies the check to allow the formula in this case.  The idea is
that neither of these formulae is introducing any new registers which is the
point of this early pruning as far as I understand.

In terms of set arithmetic, we now allow formulas whose used regs are a subset
of the required regs not just the other way around.

There are few more loops in the test-suite that are now successfully LSRed.  I
have benchmarked those and found very minimal change.

Fixes <rdar://problem/13965777>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207271 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 21:02:21 +00:00
Duncan P. N. Exon Smith
d9dc95709e SCC: Use the reference typedef
Actually use the `reference` typedef, and remove the private
redefinition of `pointer` since it has no users.

Using `reference` exposes a problem with r207257, which specified the
wrong `value_type` to `iterator_facade_base` (fixed that too).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207270 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 20:52:08 +00:00
Adrian Prantl
988b78a846 This reapplies r207235 with an additional bugfixes caught by the msan
buildbot - do not insert debug intrinsics before phi nodes.

Debug info for optimized code: Support variables that are on the stack and
described by DBG_VALUEs during their lifetime.

Previously, when a variable was at a FrameIndex for any part of its
lifetime, this would shadow all other DBG_VALUEs and only a single
fbreg location would be emitted, which in fact is only valid for a small
range and not the entire lexical scope of the variable. The included
dbg-value-const-byref testcase demonstrates this.

This patch fixes this by
Local
- emitting dbg.value intrinsics for allocas that are passed by reference
- dropping all dbg.declares (they are now fully lowered to dbg.values)
SelectionDAG
- renamed constructors for SDDbgValue for better readability.
- fix UserValue::match() to handle indirect values correctly
- not inserting an MMI table entries for dbg.values that describe allocas.
- lowering dbg.values that describe allocas into *indirect* DBG_VALUEs.
CodeGenPrepare
- leaving dbg.values for an alloca were they are (see comment)
Other
- regenerated/updated instcombine.ll testcase and included source

rdar://problem/16679879
http://reviews.llvm.org/D3374

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207269 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 20:49:25 +00:00
David Blaikie
31494cb6c4 MCAssembler: Simplify implementation of const variants of getSymbolData by calling one implementation from the other.
Code review feedback by Rafael Espindola on r207124.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207266 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 20:19:11 +00:00
David Blaikie
5ed33e08f3 BugPoint: Fix some memory leaks.
Patch by Kostya Serebryany.

unique_ptr would be nice, but it's a bit too much work for an area I'm
not familiar with, nor invested in, unfortunately.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207265 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 20:15:16 +00:00
David Blaikie
9c6a820aa7 DwarfUnit: Remove unused function
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207264 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 20:02:24 +00:00
David Blaikie
12d5224df6 DIE: Pass ownership of children via std::unique_ptr rather than raw pointer.
This should reduce the chance of memory leaks like those fixed in
r207240.

There's still some unclear ownership of DIEs happening in DwarfDebug.
Pushing unique_ptr and references through more APIs should help expose
the cases where ownership is a bit fuzzy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207263 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 20:00:34 +00:00
David Blaikie
172515f0be DIEEntry: Refer to the specified DIE via reference rather than pointer.
Makes some more cases (the unit tests, specifically), lexically
compatible with a change to unique_ptr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207261 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 19:33:43 +00:00
David Blaikie
d48f5efa9d DwarfUnit: return by reference from createAndAddDIE
Since this doesn't return ownership (the DIE has been added to the
specified parent already) nor return null, just return by reference.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207259 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:52:29 +00:00
Duncan P. N. Exon Smith
2d18167483 blockfreq: Further shift logic to LoopData
Move a lot of the loop-related logic that was sprinkled around the code
into `LoopData`.

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207258 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:47:04 +00:00
Duncan P. N. Exon Smith
eae0809a60 SCC: Provide operator->() through iterator_facade_base
Use the fancy new `iterator_facade_base` to add
`scc_iterator::operator->()`.  Remove other definitions where
`iterator_facade_base` does the right thing.

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207257 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:43:41 +00:00
Reed Kotler
4870dae19f enable fast isel tablegen files for Mips
Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D3498

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207256 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:36:38 +00:00
David Blaikie
5410b5acda Return DIE by reference instead of pointer from DwarfUnit::getUnitDie
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207255 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:35:57 +00:00
Duncan P. N. Exon Smith
d86dbccfef SCC: Remove non-const operator*()
<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207254 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:26:45 +00:00
David Blaikie
f6e00376e7 DwarfUnit: Suddently, DIE references, everywhere.
This'll make changing to unique_ptr ownership of DIEs easier since the
usages will now have '*' on them making them textually compatible
between unique_ptr and raw pointer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207253 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:26:14 +00:00
Duncan P. N. Exon Smith
db8c1ae04e SCC: Change clients to use const, NFC
It's fishy to be changing the `std::vector<>` owned by the iterator, and
no one actual does it, so I'm going to remove the ability in a
subsequent commit.  First, update the users.

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207252 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:24:50 +00:00
Duncan P. N. Exon Smith
5a6277a230 SCC: Doxygen-ize comments, NFC
<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207251 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:18:46 +00:00
Adrian Prantl
25c74de500 Revert "This reapplies r207130 with an additional testcase+and a missing check for"
This reverts commit 207235 to investigate msan buildbot breakage.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207250 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:18:09 +00:00
Duncan P. N. Exon Smith
ad56833808 SCC: Un-inline long functions
These are long functions that really shouldn't be inlined.  Otherwise,
no functionality change.

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207249 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:15:50 +00:00
Duncan P. N. Exon Smith
f40905c318 SCC: Remove redundant inline keywords, NFC
Functions declared in line in a class are inlined by default.  There's
no reason for the `inline` keyword.

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207248 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:10:23 +00:00
Reed Kotler
f7c84bf9ed Make sure that DSUB does not duplicate the pattern of DSUBU
Test Plan:
Run test suite to make sure there is no regression.
https://dmz-portal.mips.com/bb/builders/LLVM%20with%2064bit%20and%20delay%20slot%20optimizer%20and%20direct%20object%20emitter/builds/626

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D3497

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207247 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 18:05:00 +00:00
Saleem Abdulrasool
25bc383612 ARM: remove @llvm.arm.sevl
This intrinsic is no longer needed with the new @llvm.arm.hint(i32) intrinsic
which provides a generic, extensible manner for adding hint instructions.  This
functionality can now be represented as @llvm.arm.hint(i32 5).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207246 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:51:25 +00:00
Manman Ren
3bd471dee2 [inline cold threshold] Command line argument for inline threshold will
override the default cold threshold.

When we use command line argument to set the inline threshold, the default
cold threshold will not be used. This is in line with how we use
OptSizeThreshold. When we want a higher threshold for all functions, we
do not have to set both inline threshold and cold threshold.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207245 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:34:55 +00:00
David Blaikie
7d772dda4e Refactor some common logic in DwarfUnit::constructVariableDIE and pass non-null DIE by reference to DbgVariable::setDIE
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207244 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:32:19 +00:00
Saleem Abdulrasool
04f826c062 ARM: provide a new generic hint intrinsic
Introduce the llvm.arm.hint(i32) intrinsic that can be used to inject hints into
the instruction stream. This is particularly useful for generating IR from a
compiler where the user may inject an intrinsic (e.g. __yield). These are then
pattern substituted into the correct instruction which already existed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207242 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:24:24 +00:00
David Blaikie
5d71d87bff PR19554: Fix some memory leaks in DIEHashTest.cpp
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207240 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:07:55 +00:00
Adrian Prantl
a067162dfa Reapply r207135 without modifications.
Debug info: Let dbg.values inserted by LowerDbgDeclare inherit the location
of the dbg.value. This gets rid of tons of redundant variable DIEs in
subscopes.

rdar://problem/14874886, rdar://problem/16679936

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207236 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:01:04 +00:00
Adrian Prantl
7e96d88347 This reapplies r207130 with an additional testcase+and a missing check for
AllocaInst that was missing in one location.
Debug info for optimized code: Support variables that are on the stack and
described by DBG_VALUEs during their lifetime.

Previously, when a variable was at a FrameIndex for any part of its
lifetime, this would shadow all other DBG_VALUEs and only a single
fbreg location would be emitted, which in fact is only valid for a small
range and not the entire lexical scope of the variable. The included
dbg-value-const-byref testcase demonstrates this.

This patch fixes this by
Local
- emitting dbg.value intrinsics for allocas that are passed by reference
- dropping all dbg.declares (they are now fully lowered to dbg.values)
SelectionDAG
- renamed constructors for SDDbgValue for better readability.
- fix UserValue::match() to handle indirect values correctly
- not inserting an MMI table entries for dbg.values that describe allocas.
- lowering dbg.values that describe allocas into *indirect* DBG_VALUEs.
CodeGenPrepare
- leaving dbg.values for an alloca were they are (see comment)
Other
- regenerated/updated instcombine.ll testcase and included source

rdar://problem/16679879
http://reviews.llvm.org/D3374

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207235 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 17:01:00 +00:00
Tilmann Scheller
e1cd93134f [ARM64] When compiling for ELF in PIC mode, local symbols shouldn't go through the GOT
There's no need for local symbols to go through the GOT, in fact it seems GNU ld is not even emitting GOT entries for local symbols and will error out when trying to resolve a GOT relocation for a local symbol.

This bug triggers when bootstrapping clang on AArch64 Linux with -fPIC and the ARM64 backend. The AArch64 backend is not affected.

With this commit it's now possible to bootstrap clang on AArch64 Linux with the ARM64 backend (-fPIC, -O3).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207226 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 13:43:18 +00:00
Jiangning Liu
0c4797c31a [ARM64] Handle fp128 for parameter passing on stack
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207222 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 12:07:03 +00:00
Tim Northover
5c4d1570ca ARM64: fix assertion in ISelDAGToDAG
Also an unused variable, so double bonus!

This should deal with PR19548.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207221 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 10:48:47 +00:00
Bradley Smith
8aa927abb5 [ARM64] Print preferred aliases for SFBM/UBFM in InstPrinter
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207219 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 10:25:29 +00:00
Chandler Carruth
09d1d3d588 [LCG] During the incremental update of an SCC, switch to using the
SCCMap to test for nodes that have been re-added to the root SCC rather
than a set vector. We already have done the SCCMap lookup, we juts need
to test it in two different ways. In turn, do most of the processing of
these nodes as they go into the root SCC rather than lazily. This
simplifies the final loop to just stitch the root SCC into its
children's parent sets. No functionlatiy changed.

However, this makes a few things painfully obvious, which was my intent.
=] There is tons of repeated code introduced here and elsewhere. I'm
splitting the refactoring of that code into helpers from this change so
its clear that this is the change which switches the datastructures used
around, and the other is a pure factoring & deduplication of code
change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207217 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 09:52:44 +00:00
Kevin Qin
435b9bd9fb [ARM64] Add RUN lines for "–target arm64 –mattr=-fp-armv8" on AArch64 no-fp test.
This patch is a supplement of implementing predicate of FP, enabling aarch64 backend
no-fp tests on arm64 target for verification. During this, one bug is exposed and
fixed by this patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207215 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 09:44:20 +00:00
Kevin Qin
78eedb15c9 [ARM64] Support crc predicate on ARM64.
According to the specification, CRC is an optional extension of the
architecture.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207214 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-25 09:25:42 +00:00