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: 122676

llvm-svn: 122675

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

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

llvm-svn: 122661

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

Fixes PR8861.

llvm-svn: 122641

llvm-svn: 122638

llvm-svn: 122631

llvm-svn: 122626

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

llvm-svn: 122623

Multiple SPARC backend fixes: added Y register; updated select_cc, subx, subxcc defs/uses; 
and fixed CustomInserter.

llvm-svn: 122607

llvm-svn: 122603

supports.

llvm-svn: 122577

llvm-svn: 122560

llvm-svn: 122559

DAG scheduling during isel. Most new functionality is currently
guarded by -enable-sched-cycles and -enable-sched-hazard.

Added InstrItineraryData::IssueWidth field, currently derived from
ARM itineraries, but could be initialized differently on other targets.

Added ScheduleHazardRecognizer::MaxLookAhead to indicate whether it is
active, and if so how many cycles of state it holds.

Added SchedulingPriorityQueue::HasReadyFilter to allowing gating entry
into the scheduler's available queue.

ScoreboardHazardRecognizer now accesses the ScheduleDAG in order to
get information about it's SUnits, provides RecedeCycle for bottom-up
scheduling, correctly computes scoreboard depth, tracks IssueCount, and
considers potential stall cycles when checking for hazards.

ScheduleDAGRRList now models machine cycles and hazards (under
flags). It tracks MinAvailableCycle, drives the hazard recognizer and
priority queue's ready filter, manages a new PendingQueue, properly
accounts for stall cycles, etc.

llvm-svn: 122541

llvm-svn: 122539

llvm-svn: 122530

llvm-svn: 122528

llvm-svn: 122524

llvm-svn: 122523

If the basic block containing the BCCi64 (or BCCZi64) instruction ends with
an unconditional branch, that branch needs to be deleted before appending
the expansion of the BCCi64 to the end of the block.

llvm-svn: 122521

llvm-svn: 122513

llvm-svn: 122509

Remove/fix invalid README entries. The well thought out strcpy function doesn't return a pointer to the end of the string.

llvm-svn: 122496

llvm-svn: 122495

new gcc warning that complains on self-assignments and
self-initializations.

llvm-svn: 122458

llvm-svn: 122456

  int test(unsigned long a, unsigned long b) { return -(a < b); }
compiles to
  _test:                              ## @test
    cmpq  %rsi, %rdi                  ## encoding: [0x48,0x39,0xf7]
    sbbl  %eax, %eax                  ## encoding: [0x19,0xc0]
    ret                               ## encoding: [0xc3]
instead of
  _test:                              ## @test
    xorl  %ecx, %ecx                  ## encoding: [0x31,0xc9]
    cmpq  %rsi, %rdi                  ## encoding: [0x48,0x39,0xf7]
    movl  $-1, %eax                   ## encoding: [0xb8,0xff,0xff,0xff,0xff]
    cmovael %ecx, %eax                ## encoding: [0x0f,0x43,0xc1]
    ret                               ## encoding: [0xc3]

llvm-svn: 122451

llvm-svn: 122398

llvm-svn: 122385

llvm-svn: 122384

llvm-svn: 122381

llvm-svn: 122379

(add Y, (sete  X, 0)) -> cmp X, 1; adc  0, Y
(add Y, (setne X, 0)) -> cmp X, 1; sbb -1, Y
(sub (sete  X, 0), Y) -> cmp X, 1; sbb  0, Y
(sub (setne X, 0), Y) -> cmp X, 1; adc -1, Y

for
  unsigned foo(unsigned a, unsigned b) {
    if (a == 0) b++;
    return b;
  }
we now get:
  foo:
    cmpl  $1, %edi
    movl  %esi, %eax
    adcl  $0, %eax
    ret
instead of:
  foo:
    testl %edi, %edi
    sete  %al
    movzbl  %al, %eax
    addl  %esi, %eax
    ret

llvm-svn: 122364