predicates.  This allows us to jump thread things like:

_ZN12StringSwitchI5ColorE4CaseILj7EEERS1_RAT__KcRKS0_.exit119:
  %tmp1.i24166 = phi i8 [ 1, %bb5.i117 ], [ %tmp1.i24165, %_Z....exit ], [ %tmp1.i24165, %bb4.i114 ] 
  %toBoolnot.i87 = icmp eq i8 %tmp1.i24166, 0     ; <i1> [#uses=1]
  %tmp4.i90 = icmp eq i32 %tmp2.i, 6              ; <i1> [#uses=1]
  %or.cond173 = and i1 %toBoolnot.i87, %tmp4.i90  ; <i1> [#uses=1]
  br i1 %or.cond173, label %bb4.i96, label %_ZN12...

Where it is "obvious" that when coming from %bb5.i117 that the 'and' is always 
false.  This triggers a surprisingly high number of times in the testsuite, 
and gets us closer to generating good code for doug's strswitch testcase.

This also make a bunch of other code in jump threading redundant, I'll rip
out in the next patch.  This survived an enable-checking llvm-gcc bootstrap.

llvm-svn: 86264

from various APIs, addressing PR5325.

llvm-svn: 86231

Hans Wennborg!

llvm-svn: 86067

now-probably-dead instruction tree feeding it.

llvm-svn: 83778

done by condprop, but do it in a much more general form.  The
basic idea is that we can do a limited form of tail duplication
in the case when we have a branch on a phi.  Moving the branch
up in to the predecessor block makes instruction selection
much easier and encourages chained jump threadings.

llvm-svn: 83759

llvm-svn: 83756

llvm-svn: 83755

llvm-svn: 83754

DemoteRegToStack.  This makes it more efficient (because it isn't
creating a ton of load/stores that are eventually removed by a later
mem2reg), and more slightly more effective (because those load/stores
don't get in the way of threading).

llvm-svn: 83706

update all the callers.

llvm-svn: 82889

llvm-svn: 80766

llvm-svn: 78948

llvm-svn: 77685

llvm-svn: 77635

llvm-svn: 77494

llvm-svn: 77152

llvm-svn: 77145

Revert the ConstantInt constructors back to their 2.5 forms where possible, thanks to contexts-on-types.  More to come.

llvm-svn: 77011

instead of getAnalysis<TargetData>().

llvm-svn: 76982

llvm-svn: 76702

llvm-svn: 76598

llvm-svn: 75863

llvm-svn: 75703

This started as a small change, I swear.  Unfortunately, lots of things call the [I|F]CmpInst constructors.  Who knew!?

llvm-svn: 75200

llvm-svn: 74878

llvm-svn: 74844

llvm-svn: 74753

This was considering vector intrinsics to have cost 2, but non-vector
intrinsics to have cost 1, which is backward.

llvm-svn: 74698

a key is present in a std::map or DenseMap to use find instead.

llvm-svn: 74676

as if they were multiple uses of the same instruction.  This interacts
well with the existing loadpre that j-t does to open up many new jump
threads earlier.

llvm-svn: 73768

llvm-svn: 73755

llvm-svn: 70872

  ThreadEdge directly.  This shares the code, but is just a refactoring.
* Make JumpThreading compute the set of loop headers and avoid threading
  across them.  This prevents jump threading from forming irreducible 
  loops (goodness) but also prevents it from threading in other cases that
  are beneficial (see the comment above FindFunctionBackedges).

llvm-svn: 70820

llvm-svn: 67064

llvm-svn: 66252

their main routines.  This makes the tools print their argc/argv
commands if they crash.

llvm-svn: 66248

llvm-svn: 62529

jump threading can have bugs, who knew? ;-)

llvm-svn: 61983

jump threading has been shown to only expose problems not
have bugs itself.  I'm sure it's completely bug free! ;-)

llvm-svn: 60725

llvm-svn: 60534