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: 86861

add debug info location to an instruction.

llvm-svn: 86859

Add TargetLowering::isLegalICmpImmediate. It tells LSR what immediate can be folded into target icmp instructions.

llvm-svn: 86858

llvm-svn: 86857

llvm-svn: 86856

llvm-svn: 86855

the numbers mean.

llvm-svn: 86854

llvm-svn: 86853

llvm-svn: 86852

llvm-svn: 86851

llvm-svn: 86850

llvm-svn: 86848

llvm-svn: 86847

llvm-svn: 86846

llvm.invariant.start to be used without necessarily being paired with a call
to llvm.invariant.end.  If you run the entire optimization pipeline then such
calls are in fact deleted (adce does it), but that's actually a good thing since
we probably do want them to be zapped late in the game.  There should really be
an integration test that checks that the llvm.invariant.start call lasts long
enough that all passes that do interesting things with it get to do their stuff
before it is deleted.  But since no passes do anything interesting with it yet
this will have to wait for later.

llvm-svn: 86840

llvm-svn: 86814

llvm-svn: 86810

by default).

llvm-svn: 86807

llvm-svn: 86804

llvm-svn: 86803

llvm-svn: 86802

llvm-svn: 86797

llvm-svn: 86795

llvm-svn: 86794

The TBB and TBH instructions for Thumb2 are really handy for jump tables, but
can only branch forward. To best take advantage of them, we'd like to adjust
the basic blocks around a bit when reasonable. This patch puts basics in place
to do that, with a super-simple algorithm for backwards jump table targets that
creates a new branch after the jump table which branches backwards. Real
heuristics for reordering blocks or other modifications rather than inserting
branches will follow.

llvm-svn: 86791

start using them in a trivial way when -enable-jump-threading-lvi
is passed.  enable-jump-threading-lvi will be my playground for 
awhile.

llvm-svn: 86789

llvm-svn: 86786

llvm-svn: 86785

llvm-svn: 86784

function it's generated for.

llvm-svn: 86779

Add Triple::str() which returns the contents of the Triple as a string, as a more readable alternative to getTriple().

llvm-svn: 86773

llvm-svn: 86771

Also, add unittests for find_first_of and find_first_not_of.

llvm-svn: 86770

llvm-svn: 86769

oops, didn't mean to commit this, no harm, but add a todoops, didn't mean to commit this, no harm, but add a todoo

llvm-svn: 86768

vend value constraint information to the optimizer.

llvm-svn: 86767

llvm-svn: 86766