on X86 Atom. Some of our tests failed because the tail merging part of
the BranchFolding pass was creating new basic blocks which did not
contain live-in information. When the anti-dependency code in the Post-RA
scheduler ran, it would sometimes rename the register containing
the function return value because the fact that the return value was
live-in to the subsequent block had been lost. To fix this, it is necessary
to run the RegisterScavenging code in the BranchFolding pass.

This patch makes sure that the register scavenging code is invoked
in the X86 subtarget only when post-RA scheduling is being done.
Post RA scheduling in the X86 subtarget is only done for Atom.

This patch adds a new function to the TargetRegisterClass to control
whether or not live-ins should be preserved during branch folding.
This is necessary in order for the anti-dependency optimizations done
during the PostRASchedulerList pass to work properly when doing
Post-RA scheduling for the X86 in general and for the Intel Atom in particular.

The patch adds and invokes the new function trackLivenessAfterRegAlloc()
instead of using the existing requiresRegisterScavenging().
It changes BranchFolding.cpp to call trackLivenessAfterRegAlloc() instead of
requiresRegisterScavenging(). It changes the all the targets that
implemented requiresRegisterScavenging() to also implement
trackLivenessAfterRegAlloc().  

It adds an assertion in the Post RA scheduler to make sure that post RA
liveness information is available when it is needed.

It changes the X86 break-anti-dependencies test to use –mcpu=atom, in order
to avoid running into the added assertion.

Finally, this patch restores the use of anti-dependency checking
(which was turned off temporarily for the 3.1 release) for
Intel Atom in the Post RA scheduler.

Patch by Andy Zhang!

Thanks to Jakob and Anton for their reviews.

llvm-svn: 155395

llvm-svn: 155393

llvm-svn: 155392

llvm-svn: 155387

When building LLVM on Linux with libc++ with CMake TIME_WITH_SYS_TIME is
undefined, and HAVE_SYS_TIME_H is defined. This ends up including
sys/time.h but not time.h. Unix/TimeValue.inc requires time.h for asctime_r
and localtime. libstdc++ seems to include time.h anyway, but libc++ does
not.

Fix this by always including time.h

llvm-svn: 155382

find forward declarations in the context that the actual definition
will occur.

rdar://11291658

llvm-svn: 155380

the stated developer policy.

llvm-svn: 155373

test suite failures. The failures occur at each stage, and only get
worse, so I'm reverting all of them.

Please resubmit these patches, one at a time, after verifying that the
regression test suite passes. Never submit a patch without running the
regression test suite.

llvm-svn: 155372

llvm-svn: 155367

llvm-svn: 155366

llvm-svn: 155365

llvm-svn: 155364

Original commit message:

Defer some shl transforms to DAGCombine.

The shl instruction is used to represent multiplication by a constant
power of two as well as bitwise left shifts. Some InstCombine
transformations would turn an shl instruction into a bit mask operation,
making it difficult for later analysis passes to recognize the
constsnt multiplication.

Disable those shl transformations, deferring them to DAGCombine time.
An 'shl X, C' instruction is now treated mostly the same was as 'mul X, C'.

These transformations are deferred:

  (X >>? C) << C   --> X & (-1 << C)  (When X >> C has multiple uses)
  (X >>? C1) << C2 --> X << (C2-C1) & (-1 << C2)   (When C2 > C1)
  (X >>? C1) << C2 --> X >>? (C1-C2) & (-1 << C2)  (When C1 > C2)

The corresponding exact transformations are preserved, just like
div-exact + mul:

  (X >>?,exact C) << C   --> X
  (X >>?,exact C1) << C2 --> X << (C2-C1)
  (X >>?,exact C1) << C2 --> X >>?,exact (C1-C2)

The disabled transformations could also prevent the instruction selector
from recognizing rotate patterns in hash functions and cryptographic
primitives. I have a test case for that, but it is too fragile.

llvm-svn: 155362

The problem is that the struct file_status on UNIX systems has two
members called st_dev and st_ino; those are also members of the
struct stat, and they are reserved identifiers which can also be
provided as #define (and this is the case for st_dev on Hurd).
The solution (attached) is to rename them, for example adding a
"fs_" prefix (= file status) to them.

Patch by Pino Toscano

llvm-svn: 155354

Fix issue 67 by checking that the interface functions weren't redefined in the compiled source file.

llvm-svn: 155346

llvm-svn: 155341

Use MVT instead of EVT through all of LowerVECTOR_SHUFFLEtoBlend and not just the switch. Saves a little bit of binary size.

llvm-svn: 155339

Make getZeroVector and getOnesVector more alike as far as how they detect 128-bit versus 256-bit vectors. Be explicit about both sizes and use llvm_unreachable. Similar changes to getLegalSplat.

llvm-svn: 155337

llvm-svn: 155336

Tidy up spacing in LowerVECTOR_SHUFFLEtoBlend. Remove code that checks if shuffle operand has a different type than the the shuffle result since it can never happen.

llvm-svn: 155333

llvm-svn: 155332

llvm-svn: 155331

llvm-svn: 155330

fixes an assert reading "1239123123123123" when the result is already 64-bit.

llvm-svn: 155329

llvm-svn: 155328

intructions are processed. So there's no need to look at them if they're used as
operands of other instructions.

llvm-svn: 155327

Make Extract128BitVector and Insert128BitVector take an unsigned instead of an ConstantNode SDValue. getConstant was almost always called just before only to have the functions take it apart and build a new ConstantSDNode.

llvm-svn: 155325

llvm-svn: 155321

Make calls to getVectorShuffle more consistent. Use shuffle VT for calls to getUNDEF instead of requerying. Use &Mask[0] instead of Mask.data().

llvm-svn: 155320

llvm-svn: 155319

Simplify code by converting multiple places that were manually concatenating 128-bit vectors to use either CONCAT_VECTORS or a helper function. CONCAT_VECTORS will itself be lowered to the same pattern as before. The helper function is needed for concats of BUILD_VECTORs since getNode(CONCAT_VECTORS) will just return a large BUILD_VECTOR and we may be trying to lower large BUILD_VECTORS when this occurs.

llvm-svn: 155318

Found by valgrind.

llvm-svn: 155313

llvm-svn: 155309

llvm-svn: 155307

names. This saves collecting types we normally don't care about.

llvm-svn: 155300

StringRef::getAsInteger

llvm-svn: 155298

llvm-svn: 155296

llvm-svn: 155294

llvm-svn: 155291

Thanks to Andy Gibbs, to report the issue.

llvm-svn: 155287