llvm-svn: 122700

in the PR, the pass could break LCSSA form when inserting preheaders.  It probably
would be easy enough to fix this, but since currently we always go into LCSSA form
after running this pass, doing so is not urgent.

llvm-svn: 122695

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

size of a loop header instead of its own code size estimator.
This allows it to handle bitcasts etc more precisely.

llvm-svn: 122681

llvm-svn: 122678

maintains the guarantee that the DenseSet expects two elements it contains to
not go from inequal to equal under its nose.

As a side-effect, this also lets us switch from iterating to a fixed-point to
actually maintaining a work queue of functions to look at again, and we don't
add thunks to our work queue so we don't need to detect and ignore them.

llvm-svn: 122677

llvm-svn: 122676

llvm-svn: 122675

loop idiom pass exposed.

llvm-svn: 122674

llvm-svn: 122667

earlyclobber stuff. This should fix PRs 2313 and 8157.

Unfortunately, no testcase, since it'd be dependent on register
assignments.

llvm-svn: 122663

new testcase.

llvm-svn: 122662

is the wrong hammer for this nail, and is probably right.

llvm-svn: 122661

aggressively.  In practice, this doesn't help anything though,
see the todo.

llvm-svn: 122660

should be correct now.

llvm-svn: 122659

llvm-svn: 122658

numbering, in which it considers (for example) "%a = add i32 %x, %y" and
"%b = add i32 %x, %y" to be equal because the operands are equal and the
result of the instructions only depends on the values of the operands.
This has almost no effect (it removes 4 instructions from gcc-as-one-file),
and perhaps slows down compilation: I measured a 0.4% slowdown on the large
gcc-as-one-file testcase, but it wasn't statistically significant.

llvm-svn: 122654

llvm-svn: 122653

llvm-svn: 122652

is necessary for executing the custom command that runs the
assember. Fixes PR8877.

llvm-svn: 122649

operands are visited before the instructions themselves.

llvm-svn: 122647

llvm-svn: 122645

llvm-svn: 122642

Fixes PR8861.

llvm-svn: 122641

llvm-svn: 122638

llvm-svn: 122637

llvm-svn: 122636

with 2-address instructions, for about a 3.5% speedup of StrongPHIElimination on
403.gcc.

llvm-svn: 122635

llvm-svn: 122632

llvm-svn: 122631

llvm-svn: 122630

llvm-svn: 122628

process those instructions that define phi sources. This is a 47% speedup of
StrongPHIElimination compile time on 403.gcc.

llvm-svn: 122627

llvm-svn: 122626

llvm-svn: 122625

llvm-svn: 122624

CMake: Add disabling optimization on MSVC8 and MSVC10 as workaround for some files in Target/ARM and Target/X86.

llvm-svn: 122623

llvm-svn: 122617