undefined result. This adds new ISD nodes for the new semantics,
selecting them when the LLVM intrinsic indicates that the undef behavior
is desired. The new nodes expand trivially to the old nodes, so targets
don't actually need to do anything to support these new nodes besides
indicating that they should be expanded. I've done this for all the
operand types that I could figure out for all the targets. Owners of
various targets, please review and let me know if any of these are
incorrect.

Note that the expand behavior is *conservatively correct*, and exactly
matches LLVM's current behavior with these operations. Ideally this
patch will not change behavior in any way. For example the regtest suite
finds the exact same instruction sequences coming out of the code
generator. That's why there are no new tests here -- all of this is
being exercised by the existing test suite.

Thanks to Duncan Sands for reviewing the various bits of this patch and
helping me get the wrinkles ironed out with expanding for each target.
Also thanks to Chris for clarifying through all the discussions that
this is indeed the approach he was looking for. That said, there are
likely still rough spots. Further review much appreciated.

llvm-svn: 146466

llvm-svn: 146461

llvm-svn: 146459

Constant pool entries with different alignment may cause more alignment
padding to be inserted. Compute the amount of padding needed, and try to
pick the location that requires the least amount of padding.

Also take the extra padding into account when the water is above the
use.

llvm-svn: 146458

llvm-svn: 146457

llvm-svn: 146456

llvm-svn: 146455

llvm-svn: 146453

llvm-svn: 146442

llvm-svn: 146440

then read the file back in to verify use-list serialization/deserialization.

llvm-svn: 146439

This should always be done as a matter of principal. I don't have a
case that exposes the problem. I just noticed this recently while
scanning the code and realized I meant to fix it long ago.

llvm-svn: 146438

autodiscovery.

llvm-svn: 146437

subdirectories to traverse into.
 - Originally I wanted to avoid this and just autoscan, but this has one key
   flaw in that new subdirectories can not automatically trigger a rerun of the
   llvm-build tool. This is particularly a pain when switching back and forth
   between trees where one has added a subdirectory, as the dependencies will
   tend to be wrong. This will also eliminates FIXME implicitly.

llvm-svn: 146436

llvm-svn: 146435

--write-llvmbuild.

llvm-svn: 146434

llvm-svn: 146433

-relocation-model=static.

llvm-svn: 146432

llvm-svn: 146431

If we create new intervals for a variable that is being spilled, then those new intervals are not guaranteed to also spill.  This means that anything reading from the original spilling value might not get the correct value if spills were missed.

Fixes <rdar://problem/10546864>

llvm-svn: 146428

llvm-svn: 146420

These modifiers simply select either the low or high D subregister of a Neon
Q register.  I've also removed the unimplemented 'p' modifier, which turns out
to be a bit different than the comment here suggests and as far as I can tell
was only intended for internal use in Apple's version of gcc.

llvm-svn: 146417

llvm-svn: 146412

llvm-svn: 146411

llvm-svn: 146409

detected in the forward-CFG DFS. This prevents the reverse-CFG from
visiting blocks inside loops after blocks that dominate them in the
case where loops have multiple exits.

No testcase, because this fixes a bug which in practice only shows
up in a full optimizer run, due to the use-list order.

This fixes rdar://10422791 and others.

llvm-svn: 146408

llvm-svn: 146407

This computes the offset of the layout sucessor block, considering its
alignment as well.

llvm-svn: 146401

llvm-svn: 146400

llvm-svn: 146397

Downgrade the alignment of the initial constant island when constant
pool entries are moved elsewhere.

This is all gated by -arm-align-constant-islands.

llvm-svn: 146391

llvm-svn: 146389

 - Fixes PR11530.

llvm-svn: 146388

llvm-svn: 146385

llvm-svn: 146384

llvm-svn: 146383

Also add an MCP member pointing to the machine constant pool.

No functional change intended.

llvm-svn: 146382

llvm-svn: 146380

llvm-svn: 146379

Original commit message:
Support/FileSystem: Implement canonicalize.

llvm-svn: 146378