The Cost field is removed. It was only being used in a very limited way,
to indicate when the scheduler should attempt to protect a live register,
and it isn't really needed to do that. If we ever want the scheduler to
start inserting copies in non-prohibitive situations, we'll have to
rethink some things anyway.

A Latency field is added. Instead of giving each node a single
fixed latency, each edge can have its own latency. This will eventually
be used to model various micro-architecture properties more accurately.

The PointerIntPair class and an internal union are now used, which
reduce the overall size.

llvm-svn: 60806

invalidateCachedPointerInfo.  Thanks to Bill for sending me
a testcase.

llvm-svn: 60805

llvm-svn: 60804

target-independent way of determining overflow on multiplication. It's very
tricky. Patch by Zoltan Varga!

llvm-svn: 60800

of a pointer.  This allows is to catch more equivalencies.  For example,
the type_lists_compatible_p function used to require two iterations of
the gvn pass (!) to delete its 18 redundant loads because the first pass
would CSE all the addressing computation cruft, which would unblock the
second memdep/gvn passes from recognizing them.  This change allows
memdep/gvn to catch all 18 when run just once on the function (as is 
typical :) instead of just 3.

On all of 403.gcc, this bumps up the # reundandancies found from:

     63 gvn    - Number of instructions PRE'd
 153991 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted
to:
     63 gvn    - Number of instructions PRE'd
 154137 gvn    - Number of instructions deleted
  50185 gvn    - Number of loads deleted

+120 loads deleted isn't bad.

llvm-svn: 60799

essential problem was that the DAG can contain
random unused nodes which were never analyzed.
When remapping a value of a node being processed,
such a node may become used and need to be analyzed;
however due to operands being transformed during
analysis the node may morph into a different one.
Users of the morphing node need to be updated, and
this wasn't happening.  While there I added a bunch
of documentation and sanity checks, so I (or some
other poor soul) won't have to scratch their head
over this stuff so long trying to remember how it
was all supposed to work next time some obscure
problem pops up!  The extra sanity checking exposed
a few places where invariants weren't being preserved,
so those are fixed too.  Since some of the sanity
checking is expensive, I added a flag to turn it
on.  It is also turned on when building with
ENABLE_EXPENSIVE_CHECKS=1.

llvm-svn: 60797

tricks based on readnone/readonly functions.

Teach memdep to look past readonly calls when analyzing
deps for a readonly call.  This allows elimination of a
few more calls from 403.gcc:

before:
     63 gvn    - Number of instructions PRE'd
 153986 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted

after:
     63 gvn    - Number of instructions PRE'd
 153991 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted

5 calls isn't much, but this adds plumbing for the next change.

llvm-svn: 60794

load dependence queries.  This allows GVN to eliminate a few more
instructions on 403.gcc:

 152598 gvn    - Number of instructions deleted
  49240 gvn    - Number of loads deleted
after:
 153986 gvn    - Number of instructions deleted
  50069 gvn    - Number of loads deleted

llvm-svn: 60786

pointer stuff from it, simplifying the code a bit.

llvm-svn: 60783

MemDep::getNonLocalPointerDependency method.  There are
some open issues with this (missed optimizations) and
plenty of future work, but this does allow GVN to eliminate
*slightly* more loads (49246 vs 49033).

Switching over now allows simplification of the other code
path in memdep.

llvm-svn: 60780

llvm-svn: 60779

llvm-svn: 60776

llvm-svn: 60771

llvm-svn: 60770

llvm-svn: 60769

llvm-svn: 60755

llvm-svn: 60754

llvm-svn: 60753

the first block of a query specially.  This makes the "complete query
caching" subsystem more effective, avoiding predecessor queries.  This
speeds up GVN another 4%.

llvm-svn: 60752

and split its inner loop out into a new GetNonLocalInfoForBlock
function.  No functionality change.

llvm-svn: 60751

llvm-svn: 60750

one of its operand.

llvm-svn: 60749

llvm-svn: 60748

This speeds up the new GVN by another 3%

llvm-svn: 60747

position instead of using a full sort. This speeds up GVN by ~4% with the
new memdep stuff.

llvm-svn: 60746

pred iterator.

llvm-svn: 60745

queries.  This speeds up GVN using the new queries (not yet
checked in) by just over 10%.

llvm-svn: 60743

Fix the shift amount when unrolling a vector shift into scalar shifts.
Fix problem in getShuffleScalarElt where it assumes that the input of
a bit convert must be a vector.

llvm-svn: 60740

on test/CodeGen/Generic/2007-06-06-CriticalEdgeLandingPad.

llvm-svn: 60739

- Change default scheduling preference to list-burr, which produces somewhat
  better code than the default. Could also use list-tdrr, but need to ask
  dev list about the appropriate handy mnemonic before commiting.

llvm-svn: 60738

complete. For instance, it lowers the common case into this less-than-optimal
code:

        addl    %ecx, %eax
        seto    %cl
        testb   %cl, %cl
        jne     LBB1_2  ## overflow

instead of:

        addl    %ecx, %eax
        jo      LBB1_2  ## overflow

That will come in a future commit.

llvm-svn: 60737

pipeline model.

llvm-svn: 60733

for spotting these!

llvm-svn: 60728

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: 60711

llvm-svn: 60707

llvm-svn: 60705

Thanks Duncan!

llvm-svn: 60702

llvm-svn: 60701

llvm-svn: 60697