clears out more information than just the stored backedge taken count.

llvm-svn: 85664

the loop exiting block dominates the latch block; if ScalarEvolution
can prove that the trip-count is finite, that's sufficient.

llvm-svn: 85165

exact backedge taken count, when checking for infinite loops. This allows
it to delete loops with multiple exit conditions.

llvm-svn: 84952

llvm-svn: 80766

and use this to simplify more code.

llvm-svn: 75722

This way ScalarEvolution can examine the loop to determine what state
it needs to update, if it chooses.

llvm-svn: 75029

llvm-svn: 74918

llvm-svn: 73906

the optimizers about this.  For example, a readonly
function with no uses cannot be removed unless it is
also marked nounwind.

llvm-svn: 71071

CallbackVH, with fixes. allUsesReplacedWith need to
walk the def-use chains and invalidate all users of a
value that is replaced. SCEVs of users need to be
recalcualted even if the new value is equivalent. Also,
make forgetLoopPHIs walk def-use chains, since any
SCEV that depends on a PHI should be recalculated when
more information about that PHI becomes available.

llvm-svn: 70927

llvm-svn: 70661

makes ScalarEvolution::deleteValueFromRecords, and it's code that
subtly needed to be called before ReplaceAllUsesWith, unnecessary.

It also makes ValueDeletionListener unnecessary.

llvm-svn: 70645

deleting it.  This will let ScalarEvolution be more complete about
updating its records.

llvm-svn: 70632

to more accurately describe what it does. Expand its doxygen comment
to describe what the backedge-taken count is and how it differs
from the actual iteration count of the loop. Adjust names and
comments in associated code accordingly.

llvm-svn: 65382

llvm-svn: 65359

so that ScalarEvolution doesn't hang onto a dangling Loop*, which
could be a problem if another Loop happens to get allocated at the
same address.

llvm-svn: 65323

LoopPass*.
 - Although less precise, this means they can be used in clients
   without RTTI (who would otherwise need to include LoopPass.h, which
   eventually includes things using dynamic_cast). This was the
   simplest solution that presented itself, but I am happy to use a
   better one if available.

llvm-svn: 58010

llvm-svn: 55779

llvm-svn: 52651

llvm-svn: 51666

Also, use SCEV to determine the trip count of the loop, which is more powerful
and accurate that Loop::getTripCount.

llvm-svn: 51179

several things that were neither in an anonymous namespace nor static
but not intended to be global.

llvm-svn: 51017

Patch by Matthijs Kooijman!

llvm-svn: 50861

We need to update PHIs containing the exiting block, not the exit block.  We really should come up with better names for these.

llvm-svn: 50770

llvm-svn: 50473

of this was suggested by Chris.

llvm-svn: 50441

llvm-svn: 50437

llvm-svn: 50436

llvm-svn: 50406

llvm-svn: 50384

llvm-svn: 50383

the trip count.

llvm-svn: 50382