branch folding can now compile stuff like this:

void foo(int W, int X, int Y, int Z) {
  if (W & 1) {
    for (; X;--X) bar();
  } else if (W & 2) {
    for (; Y;--Y) bar();
  } else if (W & 4) {
    for (; Z;--Z) bar();
  } else if (W & 8) {
    for (; W;--W) bar();
  }

  if (W) {
    bar();
  }
}

contrived testcase where loops exits all end up merging together.  To have
the loop merges be:

...
        cmplw cr0, r30, r27
        bne cr0, LBB1_14        ;bb38
LBB1_16:        ;cond_next48.loopexit
        mr r27, r29
LBB1_20:        ;cond_next48
        cmplwi cr0, r27, 0
        beq cr0, LBB1_22        ;UnifiedReturnBlock
...

instead of:


...
        cmplw cr0, r30, r27
        bne cr0, LBB1_14        ;bb38
LBB1_16:        ;cond_next48.loopexit
        mr r27, r29
        b LBB1_20       ;cond_next48
LBB1_17:        ;cond_next48.loopexit1
        b LBB1_20       ;cond_next48
LBB1_18:        ;cond_next48.loopexit2
        b LBB1_20       ;cond_next48
LBB1_19:        ;cond_next48.loopexit3
LBB1_20:        ;cond_next48
        cmplwi cr0, r27, 0
        beq cr0, LBB1_22        ;UnifiedReturnBlock
...


This is CodeGen/PowerPC/branch-opt.ll

llvm-svn: 31006

llvm-svn: 31005

llvm-svn: 31003

llvm-svn: 31002

llvm-svn: 31001

It now correctly deletes unreachable blocks and blocks that are empty.

llvm-svn: 31000

llvm-svn: 30999

llvm-svn: 30998

llvm-svn: 30997

llvm-svn: 30996

llvm-svn: 30995

llvm-svn: 30994

llvm-svn: 30993

llvm-svn: 30992

llvm-svn: 30991

llvm-svn: 30990

(vector_shuffle
  (vbitconvert (vbuildvector (copyfromreg v4f32), 1, v4f32), 4, f32),
  (undef, undef, undef, undef), (0, 0, 0, 0), 4, f32)
to the
  vbitconvert
is a very bad idea.

llvm-svn: 30989

llvm-svn: 30988

llvm-svn: 30987

llvm-svn: 30986

llvm-svn: 30985

llvm-svn: 30984

llvm-svn: 30983

llvm-svn: 30982

llvm-svn: 30981

llvm-svn: 30980

llvm-svn: 30979

llvm-svn: 30978

llvm-svn: 30977

llvm-svn: 30976

llvm-svn: 30975

llvm-svn: 30974

llvm-svn: 30973

Passing isel root and use operands to ComplexPattern functions, these should do the usual load folding checks as well.

llvm-svn: 30972

llvm-svn: 30971

llvm-svn: 30970

llvm-svn: 30969

llvm-svn: 30968

llvm-svn: 30967

llvm-svn: 30966