Branch instructions don't produce values, so there's no need to generate a value number for them.  This
avoids adding them to the various value numbering tables, resulting in a minor (~3%) speedup for GVN
on 40.gcc.

llvm-svn: 122819

llvm-svn: 122817

llvm-svn: 122815

when safe.

The testcase is basically this nested loop:
void foo(char *X) {
  for (int i = 0; i != 100; ++i) 
    for (int j = 0; j != 100; ++j)
      X[j+i*100] = 0;
}

which gets turned into a single memset now.  clang -O3 doesn't optimize
this yet though due to a phase ordering issue I haven't analyzed yet.

llvm-svn: 122806

instruction *after* the store.  The store will always be deleted
if the transformation kicks in, so we'd do an N^2 scan of every
loop block.  Whoops.

llvm-svn: 122805

CodeGenPrepare (which is the default behavior).

llvm-svn: 122801

FunctionPass. It probably doesn't have a reason to be a LoopPass, as it will
probably drop the simple fixed point and either use RPO iteration or Duncan's
approach in instsimplify of only revisiting instructions that have changed.

The next step is to preserve LoopSimplify. This looks like it won't be too hard,
although the pass manager doesn't actually seem to respect when non-loop passes
claim to preserve LCSSA or LoopSimplify. This will have to be fixed.

llvm-svn: 122791

stop setting NSW: signed overflow is possible.  Thanks to Dan
for pointing these out.

llvm-svn: 122790

llvm-svn: 122788

Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,
have GlobalsModRef handle this conservatively by simply removing the value from its maps.

llvm-svn: 122787

invalidated by stores, so they can be handled as 'simple'
operations.

llvm-svn: 122785

almost-but-not-quite-identical code.  No intended functionality change.

llvm-svn: 122760

that are allowed to have metadata operands are intrinsic calls,
and the only ones that take metadata currently return void.
Just reject all void instructions, which should not be value
numbered anyway.  To future proof things, add an assert to the
getHashValue impl for calls to check that metadata operands 
aren't present.

llvm-svn: 122759

nested values, so they can change and drop to null, which can
change the hash and cause havok.

It turns out that it isn't a good idea to value number stuff
with metadata operands anyway, so... don't.

llvm-svn: 122758

capacity on the Visited SmallPtrSet. On 403.gcc, this is about a 4.5% speedup of
CodeGenPrepare time (which itself is 10% of time spent in the backend).

This is progress towards PR8889.

llvm-svn: 122741

elimination as well.  This deletes 60 stores in 176.gcc
that largely come from bitfield code.

llvm-svn: 122736

speeding earlycse up by 6%.

llvm-svn: 122733

store->load forwarding.  This allows EarlyCSE to zap 600 more
loads from 176.gcc.

llvm-svn: 122732

by their pointer instead of using MemoryValue to wrap it.

llvm-svn: 122731

llvm-svn: 122729

On 176.gcc, this catches 13090 loads and calls, and increases the
number of simple instructions CSE'd from 29658 to 36208.

llvm-svn: 122727

llvm-svn: 122725

llvm-svn: 122724

allocator.  This speeds up early cse by about 20%

llvm-svn: 122723

llvm-svn: 122720

of instcombine that is currently in the middle of the loop pass pipeline. This
commit only checks in the pass; it will hopefully be enabled by default later.

llvm-svn: 122719

llvm-svn: 122718

Teach it to CSE the rest of the non-side-effecting instructions.

llvm-svn: 122716

Add a testcase.

llvm-svn: 122715

so that Dominators.h is *just* domtree.  Also prune #includes a bit.

llvm-svn: 122714

llvm-svn: 122713

sure that the loop we're promoting into a memcpy doesn't mutate the input
of the memcpy.  Before we were just checking that the dest of the memcpy
wasn't mod/ref'd by the loop.

llvm-svn: 122712

mess with it.  We'd rather peel/unroll it than convert all of its 
stores into memsets.

llvm-svn: 122711

blocks in a loop, instead of just the header block.  This makes it more
aggressive, able to handle Duncan's Ada examples.

llvm-svn: 122704

llvm-svn: 122703

isExitBlockDominatedByBlockInLoop is a relic of the days when domtree was 
*just* a tree and didn't have DFS numbers.  Checking DFS numbers is faster
and easier than "limiting the search of the tree".

llvm-svn: 122702

llvm-svn: 122701

header for now for memset/memcpy opportunities.  It turns out that loop-rotate
is successfully rotating loops, but *DOESN'T MERGE THE BLOCKS*, turning "for 
loops" into 2 basic block loops that loop-idiom was ignoring.

With this fix, we form many *many* more memcpy and memsets than before, including
on the "history" loops in the viterbi benchmark, which look like this:

        for (j=0; j<MAX_history; ++j) {
          history_new[i][j+1] = history[2*i][j];
        }

Transforming these loops into memcpy's speeds up the viterbi benchmark from
11.98s to 3.55s on my machine.  Woo.

llvm-svn: 122685

llvm-svn: 122683

llvm-svn: 122682