llvm-svn: 86873

tail merging support to handle more cases.
 - Recognize several cases where tail merging is beneficial even when
   the tail size is smaller than the generic threshold.
 - Make use of MachineInstrDesc::isBarrier to help detect
   non-fallthrough blocks.
 - Check for and avoid disrupting fall-through edges in more cases.

llvm-svn: 86871

- Edges are split before any phis are eliminated, so the code is SSA.

- Create a proper IR BasicBlock for the split edges.

- LiveVariables::addNewBlock now has same syntax as
  MachineDominatorTree::addNewBlock. Algorithm calculates predecessor live-out
  set rather than successor live-in set.

This feature still causes some miscompilations.

llvm-svn: 86867

llvm-svn: 86856

llvm-svn: 86855

the numbers mean.

llvm-svn: 86854

llvm-svn: 86853

llvm-svn: 86794

function it's generated for.

llvm-svn: 86779

llvm-svn: 86771

llvm-svn: 86763

llvm-svn: 86753

constant whose component type is not a legal type for the target.
(If the target ConstantPool cannot handle this type either, it has
an opportunity to merge elements.  In practice any target with
8-bit bytes must support i8 *as data*).  7320806 (partial).

llvm-svn: 86751

llvm-svn: 86748

Critical edges leading to a PHI node are split when the PHI source variable is
live out from the predecessor block. This help the coalescer eliminate more
PHI joins.

llvm-svn: 86725

Clean up some whitespace.
No functional changes.

llvm-svn: 86724

just throw them away.

llvm-svn: 86678

llvm-svn: 86642

llvm-svn: 86641

This patch forbids implicit conversion of DenseMap::const_iterator to
DenseMap::iterator which was possible because DenseMapIterator inherited
(publicly) from DenseMapConstIterator. Conversion the other way around is now
allowed as one may expect.

The template DenseMapConstIterator is removed and the template parameter
IsConst which specifies whether the iterator is constant is added to
DenseMapIterator.

Actually IsConst parameter is not necessary since the constness can be
determined from KeyT but this is not relevant to the fix and can be addressed
later.

Patch by Victor Zverovich!

llvm-svn: 86636

llvm-svn: 86634

Allow targets to specify register classes whose member registers should not be renamed to break anti-dependencies. 

llvm-svn: 86628

llvm-svn: 86601

llvm-svn: 86600

instructions. This makes CodeGen dumps significantly less noisy.

Example before:
  BL <ga:@bar>, %R0<imp-def>, %R1<imp-def,dead>, %R2<imp-def,dead>, %R3<imp-def,dead>, %R12<imp-def,dead>, %LR<imp-def,dead>, %D0<imp-def,dead>, %D1<imp-def,dead>, %D2<imp-def,dead>, %D3<imp-def,dead>, %D4<imp-def,dead>, %D5<imp-def,dead>, %D6<imp-def,dead>, %D7<imp-def,dead>, %D16<imp-def,dead>, %D17<imp-def,dead>, %D18<imp-def,dead>, %D19<imp-def,dead>, %D20<imp-def,dead>, %D21<imp-def,dead>, %D22<imp-def,dead>, %D23<imp-def,dead>, %D24<imp-def,dead>, %D25<imp-def,dead>, %D26<imp-def,dead>, %D27<imp-def,dead>, %D28<imp-def,dead>, %D29<imp-def,dead>, %D30<imp-def,dead>, %D31<imp-def,dead>, %CPSR<imp-def,dead>, %FPSCR<imp-def,dead>

Same example after:
  BL <ga:@bar>, %R0<imp-def>, %R1<imp-def,dead>, %LR<imp-def,dead>, %CPSR<imp-def,dead>, ...

llvm-svn: 86583

Fix dependencies added to model memory aliasing for post-RA scheduling. The dependencies were overly conservative for memory access that are known not to alias.

llvm-svn: 86580

llvm-svn: 86564

llvm-svn: 86522

llvm-svn: 86521

llvm-svn: 86446

llvm-svn: 86384

llvm-svn: 86354

llvm-svn: 86342

llvm-svn: 86340

  except it doesn't care if the definitions' virtual registers differ. This is
  used by machine LICM and other MI passes to perform CSE.
- Teach Thumb2InstrInfo::isIdentical() to check two t2LDRpci_pic are identical.
  Since pc relative constantpool entries are always different, this requires it
  it check if the values can actually the same.

llvm-svn: 86328

Add code to check at SelectionDAGISel::LowerArguments time to see if return values can be lowered to registers.  Coming soon, code to perform sret-demotion if return values cannot be lowered to registers

llvm-svn: 86324

A non-identity copy cannot be coalesced when the phi join destination register
is live at the copy site.

Also verify the condition that the PHI join source register is only used in
the PHI join. Otherwise the coalescing is invalid.

llvm-svn: 86322

llvm-svn: 86295

prints them with the leading '@'.

llvm-svn: 86261

llvm-svn: 86259