us to use index registers for CPI's

llvm-svn: 17082

index reg and scale

llvm-svn: 17081

  %X = and Y, constantint
  %Z = setcc %X, 0

instead of emitting:

        and %EAX, 3
        test %EAX, %EAX
        je .LBBfoo2_2   # UnifiedReturnBlock

We now emit:

        test %EAX, 3
        je .LBBfoo2_2   # UnifiedReturnBlock

This triggers 581 times on 176.gcc for example.

llvm-svn: 17080

llvm-svn: 17079

1. optional shift left
2. and x, immX
3. and y, immY
4. or z, x, y
==> rlwimi z, x, y, shift, mask begin, mask end

where immX == ~immY and immX is a run of set bits. This transformation
fires 32 times on voronoi, once on espresso, and probably several
dozen times on external benchmarks such as gcc.

To put this in terms of actual code generated for
struct B { unsigned a : 3; unsigned b : 2; };
void storeA (struct B *b, int v) { b->a = v;}
void storeB (struct B *b, int v) { b->b = v;}

Old:
_storeA:
        rlwinm r2, r4, 0, 29, 31
        lwz r4, 0(r3)
        rlwinm r4, r4, 0, 0, 28
        or r2, r4, r2
        stw r2, 0(r3)
        blr

_storeB:
        rlwinm r2, r4, 3, 0, 28
        rlwinm r2, r2, 0, 27, 28
        lwz r4, 0(r3)
        rlwinm r4, r4, 0, 29, 26
        or r2, r2, r4
        stw r2, 0(r3)
        blr

New:
_storeA:
        lwz r2, 0(r3)
        rlwimi r2, r4, 0, 29, 31
        stw r2, 0(r3)
        blr

_storeB:
        lwz r2, 0(r3)
        rlwimi r2, r4, 3, 27, 28
        stw r2, 0(r3)
        blr

llvm-svn: 17078

llvm-svn: 17077

llvm-svn: 17076

for undef.

llvm-svn: 17075

llvm-svn: 17074

llvm-svn: 17073

llvm-svn: 17072

that we undefine the macro before using its name in the definition. This
can happen on Linux if _GNU_SOURCE is defined.

llvm-svn: 17071

llvm-svn: 17070

llvm-svn: 17069

flag rotate left word immediate then mask insert (rlwimi) as a two-address
instruction, and update the ISel usage of the instruction accordingly.

This will allow us to properly schedule rlwimi, and use it to efficiently
codegen bitfield operations.

llvm-svn: 17068

llvm-svn: 17067

ugly and giant constnat exprs in some programs.

llvm-svn: 17066

involving %B instead of allowing any geps except %A's.

llvm-svn: 17065

* Wrap at 80 cols

llvm-svn: 17064

been defined yet!

llvm-svn: 17063

llvm-svn: 17062

llvm-svn: 17061

llvm-svn: 17059

llvm-svn: 17058

llvm-svn: 17057

llvm-svn: 17056

llvm-svn: 17055

llvm-svn: 17054

llvm-svn: 17053

llvm-svn: 17052

llvm-svn: 17051

llvm-svn: 17050

now compile:

'foo() {}' into "ret" instead of "mov EAX, 0; ret"

llvm-svn: 17049

llvm-svn: 17048

llvm-svn: 17047

llvm-svn: 17046

llvm-svn: 17045

ignore unreachable instructions

llvm-svn: 17044

llvm-svn: 17043

that are initialized with undef.  When promoting malloc to a global, start out
initialized to undef

llvm-svn: 17042