1) For 8-bit registers try to use first the ones that are parts of the
   same register (AL then AH). This way we only alias 2 16/32-bit
   registers after allocating 4 8-bit variables.

2) Move EBX as the last register to allocate. This will cause less
   spills to happen since we will have 8-bit registers available up to
   register excaustion (assuming we use the allocation order). It
   would be nice if we could push all of the 8-bit aliased registers
   towards the end but we much prefer to keep callee saved register to
   the end to avoid saving them on entry and exit of the function.

For example this gives a slight reduction of spills with linear scan
on 164.gzip.

Before:

11221 asm-printer           - Number of machine instrs printed
  975 spiller               - Number of loads added
  675 spiller               - Number of stores added
  398 spiller               - Number of register spills

After:

11182 asm-printer           - Number of machine instrs printed
  952 spiller               - Number of loads added
  652 spiller               - Number of stores added
  386 spiller               - Number of register spills

llvm-svn: 11996

their names more decriptive. A name consists of the base name, a
default operand size followed by a character per operand with an
optional special size. For example:

ADD8rr -> add, 8-bit register, 8-bit register

IMUL16rmi -> imul, 16-bit register, 16-bit memory, 16-bit immediate

IMUL16rmi8 -> imul, 16-bit register, 16-bit memory, 8-bit immediate

MOVSX32rm16 -> movsx, 32-bit register, 16-bit memory

llvm-svn: 11995

llvm-svn: 11994

Replace uses of addZImm with addImm.

llvm-svn: 11992

block loops.

llvm-svn: 11990

Note that this is a band-aid put over a band-aid.  This just undisables
tail duplication in on very specific case that it seems to work in.

llvm-svn: 11989

llvm-svn: 11987

llvm-svn: 11986

llvm-svn: 11984

llvm-svn: 11983

llvm-svn: 11982

llvm-svn: 11981

llvm-svn: 11979

llvm-svn: 11977

llvm-svn: 11974

llvm-svn: 11973

to denote this fact.

llvm-svn: 11972

denote this fact.

llvm-svn: 11971

parse. The name is now I (operand size)*. For example:

Im32 -> instruction with 32-bit memory operands.

Im16i8 -> instruction with 16-bit memory operands and 8 bit immediate
          operands.

llvm-svn: 11970

operand but their sizes differ.

llvm-svn: 11969

the size of the immediate and the memory operand on instructions that
use them. This resolves problems with instructions that take both a
memory and an immediate operand but their sizes differ (i.e. ADDmi32b).

llvm-svn: 11967

llvm-svn: 11966

and br->br code and generalizing it.  This allows us to compile code like this:

int test(Instruction *I) {
  if (isa<CastInst>(I))
    return foo(7);
  else if (isa<BranchInst>(I))
    return foo(123);
  else if (isa<UnwindInst>(I))
    return foo(1241);
  else if (isa<SetCondInst>(I))
    return foo(1);
  else if (isa<VAArgInst>(I))
    return foo(42);
  return foo(-1);
}

into:

int %_Z4testPN4llvm11InstructionE("struct.llvm::Instruction"* %I) {
entry:
        %tmp.1.i.i.i.i.i.i.i = getelementptr "struct.llvm::Instruction"* %I, long 0, ubyte 4            ; <uint*> [#uses=1]
        %tmp.2.i.i.i.i.i.i.i = load uint* %tmp.1.i.i.i.i.i.i.i          ; <uint> [#uses=2]
        %tmp.2.i.i.i.i.i.i = seteq uint %tmp.2.i.i.i.i.i.i.i, 27                ; <bool> [#uses=0]
        switch uint %tmp.2.i.i.i.i.i.i.i, label %endif.0 [
                 uint 27, label %then.0
                 uint 2, label %then.1
                 uint 5, label %then.2
                 uint 14, label %then.3
                 uint 15, label %then.3
                 uint 16, label %then.3
                 uint 17, label %then.3
                 uint 18, label %then.3
                 uint 19, label %then.3
                 uint 32, label %then.4
        ]
...

As well as handling the cases in 176.gcc and many other programs more effectively.

llvm-svn: 11964

immediately abort due to lack of an instruction selector. :)

llvm-svn: 11963

llvm-svn: 11960

llvm-svn: 11959

llvm-svn: 11958

llvm-svn: 11957

llvm-svn: 11956

llvm-svn: 11955

llvm-svn: 11954

Do not just inject a new prototype.

llvm-svn: 11951

operands. The X86 backend doesn't handle them properly right now.

llvm-svn: 11944

Create a new AddUsesToWorkList method
optimize memmove/set/cpy of zero bytes to a noop.

llvm-svn: 11941

llvm-svn: 11940

llvm-svn: 11939

function, as long as the loop isn't the only one in that function. This should
help debugging passes easier with BugPoint.

llvm-svn: 11936

a new function, taking care of inputs and outputs.

llvm-svn: 11935

llvm-svn: 11933

llvm-svn: 11932