llvm-svn: 12837

llvm-svn: 12836

  1. If an incoming argument is dead, don't load it from the stack
  2. Do not code gen noop copies at all (ie, cast int -> uint), not even to
     a move.  This should reduce register pressure for allocators that are
     unable to coallesce away these copies in some cases.

llvm-svn: 12835

llvm-svn: 12834

llvm-svn: 12833

llvm-svn: 12832

llvm-svn: 12831

llvm-svn: 12830

llvm-svn: 12829

llvm-svn: 12826

llvm-svn: 12825

llvm-svn: 12824

llvm-svn: 12823

llvm-svn: 12822

llvm-svn: 12821

llvm-svn: 12820

Canonicalize add of sign bit constant into a xor

llvm-svn: 12819

llvm-svn: 12818

and a bit more powerful

llvm-svn: 12817

llvm-svn: 12816

llvm-svn: 12815

llvm-svn: 12814

llvm-svn: 12813

llvm-svn: 12811

llvm-svn: 12810

llvm-svn: 12809

don't write to memory

llvm-svn: 12808

call and invoke instructions that are known to not write to memory.

llvm-svn: 12807

llvm-svn: 12806

llvm-svn: 12805

llvm-svn: 12804

llvm-svn: 12803

llvm-svn: 12802

eliminating the shifts

llvm-svn: 12801

This transforms code like this:

   %C = or %A, %B
   %D = select %cond, %C, %A
into:
   %C = select %cond, %B, 0
   %D = or %A, %C

Since B is often a constant, the select can often be eliminated.  In any case,
this reduces the usage count of A, allowing subsequent optimizations to happen.

This xform applies when the operator is any of:
  add, sub, mul, or, xor, and, shl, shr

llvm-svn: 12800

llvm-svn: 12799

  if (C)
    V1 |= V2;

into:
  Vx = V1 | V2;
  V1 = select C, V1, Vx

when the expression can be evaluated unconditionally and is *cheap* to
execute.  This limited form of if conversion is quite handy in lots of cases.
For example, it turns this testcase into straight-line code:

int in0 ; int in1 ; int in2 ; int in3 ;
int in4 ; int in5 ; int in6 ; int in7 ;
int in8 ; int in9 ; int in10; int in11;
int in12; int in13; int in14; int in15;
long output;

void mux(void) {
  output =
      (in0   ?  0x00000001 : 0) | (in1   ?  0x00000002 : 0) |
      (in2   ?  0x00000004 : 0) | (in3   ?  0x00000008 : 0) |
      (in4   ?  0x00000010 : 0) | (in5   ?  0x00000020 : 0) |
      (in6   ?  0x00000040 : 0) | (in7   ?  0x00000080 : 0) |
      (in8   ?  0x00000100 : 0) | (in9   ?  0x00000200 : 0) |
      (in10  ?  0x00000400 : 0) | (in11  ?  0x00000800 : 0) |
      (in12  ?  0x00001000 : 0) | (in13  ?  0x00002000 : 0) |
      (in14  ?  0x00004000 : 0) | (in15  ?  0x00008000 : 0) ;
}

llvm-svn: 12798

llvm-svn: 12797

llvm-svn: 12796

is listed first and the address is listed second.

llvm-svn: 12795