preserve loop simplify of enclosing loops.

The problem here starts with LoopRotation which ends up cloning code out
of the latch into the new preheader it is buidling. This can create
a new edge from the preheader into the exit block of the loop which
breaks LoopSimplify form. The code tries to fix this by splitting the
critical edge between the latch and the exit block to get a new exit
block that only the latch dominates. This sadly isn't sufficient.

The exit block may be an exit block for multiple nested loops. When we
clone an edge from the latch of the inner loop to the new preheader
being built in the outer loop, we create an exiting edge from the outer
loop to this exit block. Despite breaking the LoopSimplify form for the
inner loop, this is fine for the outer loop. However, when we split the
edge from the inner loop to the exit block, we create a new block which
is in neither the inner nor outer loop as the new exit block. This is
a predecessor to the old exit block, and so the split itself takes the
outer loop out of LoopSimplify form. We need to split every edge
entering the exit block from inside a loop nested more deeply than the
exit block in order to preserve all of the loop simplify constraints.

Once we try to do that, a problem with splitting critical edges
surfaces. Previously, we tried a very brute force to update LoopSimplify
form by re-computing it for all exit blocks. We don't need to do this,
and doing this much will sometimes but not always overlap with the
LoopRotate bug fix. Instead, the code needs to specifically handle the
cases which can start to violate LoopSimplify -- they aren't that
common. We need to see if the destination of the split edge was a loop
exit block in simplified form for the loop of the source of the edge.
For this to be true, all the predecessors need to be in the exact same
loop as the source of the edge being split. If the dest block was
originally in this form, we have to split all of the deges back into
this loop to recover it. The old mechanism of doing this was
conservatively correct because at least *one* of the exiting blocks it
rewrote was the DestBB and so the DestBB's predecessors were fixed. But
this is a much more targeted way of doing it. Making it targeted is
important, because ballooning the set of edges touched prevents
LoopRotate from being able to split edges *it* needs to split to
preserve loop simplify in a coherent way -- the critical edge splitting
would sometimes find the other edges in need of splitting but not
others.

Many, *many* thanks for help from Nick reducing these test cases
mightily. And helping lots with the analysis here as this one was quite
tricky to track down.

llvm-svn: 200393

llvm-svn: 200391

llvm-svn: 200390

After all hard work to implement the EHABI and with the test-suite
passing, it's time to turn it on by default and allow users to
disable it as a work-around while we fix the eventual bugs that show
up.

This commit also remove the -arm-enable-ehabi-descriptors, since we
want the tables to be printed every time the EHABI is turned on
for non-Darwin ARM targets.

Although MCJIT EHABI is not working yet (needs linking with the right
libraries), this commit also fixes some relocations on MCJIT regarding
the EH tables/lib calls, and update some tests to avoid using EH tables
when none are needed.

The EH tests in the test-suite that were previously disabled on ARM
now pass with these changes, so a follow-up commit on the test-suite
will re-enable them.

llvm-svn: 200388

This commit seeks to do two things:
 - Run the surfeit of tests under the Darwin dialect.  This ends up
   affecting tests which assumed that spaces could deliminate arguments.
 - The GAS dialect tests should limit their surface area to things that
   could plausibly work under GAS. For example, Darwin style arguments
   have no business being in such a test.

llvm-svn: 200383

llvm-svn: 200378

llvm-svn: 200377

This makes MCAsmInfo::getExprForFDESymbol() a virtual function and overrides it in SparcMCAsmInfo.

llvm-svn: 200376

It was incompatible with --target=i686-win32.

llvm-svn: 200375

It had grown fairly inconsistent. I am about to change it quite a bit to also
use the object api when handling IR files.

llvm-svn: 200374

Otherwise, assembler (gas) fails to assemble them with error message "operation
combines symbols in different segments". This is because MC computes
pc_rel entries with subtract expression between labels from different sections.

llvm-svn: 200373

because of the inside-out run of LoopSimplify in the LoopPassManager and
the fact that LoopSimplify couldn't be "preserved" across two
independent LoopPassManagers.

Anyways, in that case, IndVars wasn't correctly preserving an LCSSA PHI
node because it thought it was rewriting (via SCEV) the incoming value
to a loop invariant value. While it may well be invariant for the
current loop, it may be rewritten in terms of an enclosing loop's
values. This in and of itself is fine, as the LCSSA PHI node in the
enclosing loop for the inner loop value we're rewriting will have its
own LCSSA PHI node if used outside of the enclosing loop. With me so
far?

Well, the current loop and the enclosing loop may share an exiting
block and exit block, and when they do they also share LCSSA PHI nodes.
In this case, its not valid to RAUW through the LCSSA PHI node.

Expected crazy test included.

llvm-svn: 200372

When estimating register pressure, don't count the induction variable mulitple
times. It is unlikely to be unrolled. This is currently disabled and hidden
behind a flag ("enable-ind-var-reg-heur").

llvm-svn: 200371

llvm-svn: 200370

[SparcV9] Use correct register class (I64RegClass) to hold the address of  _GLOBAL_OFFSET_TABLE_ in sparcv9.

llvm-svn: 200368

This is a bit more convenient for some callers, but more importantly, it is
easier to implement correctly. Doing this removes the patching of already
printed data that was used for fastcall, fixing a crash with private fastcall
symbols.

llvm-svn: 200367

When the scalar compare is between floating point and operands are
vector, we custom lower SELECT_CC to use NEON SIMD compare for
generating less instructions.

llvm-svn: 200365

llvm-svn: 200361

The default value of this attribute is PTHREAD_PROCESS_PRIVATE, so
there's no point in calling pthread_mutexattr_setpshared() to set
that.

See: http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_mutexattr_getpshared.html

This removes some ifdefs that tend to need to be extended for other
platforms (e.g. for NaCl).

Note that this call was in the first implementation of Mutex, added in
r22403, so it doesn't appear to have been added in response to a
performance problem.

Differential Revision: http://llvm-reviews.chandlerc.com/D2633

llvm-svn: 200360

Use an RAII object Instead of inserting a call to
AsmLexer::setSkipSpace(true) in all error paths.

No functional change.

llvm-svn: 200358

This will be better with c++11, but right now file_magic converts to bool,
which makes the api really easy to misuse.

llvm-svn: 200357

Oops. Don't do build tests on patches like that with --enable-targets=x86_64

llvm-svn: 200355

I assume that the name is file_type because it is the name of a c++11 type that
we will use once we convert, but at least our current implementation can look
like llvm code.

Thanks to David Blakie for the push.

llvm-svn: 200354

llvm-svn: 200353

llvm-svn: 200352

1. test that inlineasm works
2. test that relaxable instructions are re-encoded in the correct mode.

llvm-svn: 200351

The subtarget info is explicitly passed to the EncodeInstruction
method and we should use that subtarget info to influence any
encoding decisions.

llvm-svn: 200350

llvm-svn: 200349

llvm-svn: 200348

Needed to fix PR18303 to correctly re-encode the instruction if it
is relaxed.

We keep a copy of the MCSubtargetInfo to make sure that we are not
effected by future changes to the subtarget info coming from the
assembler (e.g. when parsing .code 16 directived).

llvm-svn: 200347

Add MCSubtargetInfo parameter
virtual void EmitInstToFragment(const MCInst &Inst, const MCSubtargetInfo &);
virtual void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo &);

llvm-svn: 200346

llvm-svn: 200345

llvm-svn: 200341

Reviewed at http://llvm-reviews.chandlerc.com/D2232

llvm-svn: 200340

llvm-svn: 200335

llvm-svn: 200333

As opposed to GCC/GAS the default ABI for Mips64 is n64.
Compatibility bit should be set if o32 ABI is used when targeting Mips64.

llvm-svn: 200332

Makes it easy to use BumpPtrAllocator to make a copy of StringRef strings.

llvm-svn: 200331

The code was missing the case for aggregate parameters and
hence was emitting them as .b0 type. Also fixed a couple
of comments.

llvm-svn: 200325

This improves the fix committed at revision 199683 adding the
following new target specific combine rules:

1) fold (v4i32: vselect <0,0,-1,-1>, A, B) ->
        (v4i32 (bitcast (movsd (v2i64 (bitcast A)), (v2i64 (bitcast B))) ))

2) fold (v4f32: vselect <0,0,-1,-1>, A, B) ->
        (v4f32 (bitcast (movsd (v2f64 (bitcast A)), (v2f64 (bitcast B))) ))

3) fold (v4i32: vselect <-1,-1,0,0>, A, B) ->
        (v4i32 (bitcast (movsd (v2i64 (bitcast B)), (v2i64 (bitcast A))) ))

4) fold (v4f32: vselect <-1,-1,0,0>, A, B) ->
        (v4f32 (bitcast (movsd (v2i64 (bitcast B)), (v2i64 (bitcast A))) ))

llvm-svn: 200324