a special case hack for X86, make the hack more general: if an incoming argument
register is not used in any block other than the entry block, don't copy it to
a vreg.  This helps us compile code like this:

%struct.foo = type { int, int, [0 x ubyte] }
int %test(%struct.foo* %X) {
        %tmp1 = getelementptr %struct.foo* %X, int 0, uint 2, int 100
        %tmp = load ubyte* %tmp1                ; <ubyte> [#uses=1]
        %tmp2 = cast ubyte %tmp to int          ; <int> [#uses=1]
        ret int %tmp2
}

to:

_test:
        lbz r3, 108(r3)
        blr

instead of:

_test:
        lbz r2, 108(r3)
        or r3, r2, r2
        blr

The (dead) copy emitted to copy r3 into a vreg for extra-block uses was
increasing the live range of r3 past the load, preventing the coallescing.

This implements CodeGen/PowerPC/reg-coallesce-simple.ll

llvm-svn: 24115

allows us to lower legal return types to something else, to meet ABI
requirements (such as that i64 be returned in two i32 regs on Darwin/ppc).

llvm-svn: 23802

sized stack object if either the array size or the type size is zero.

llvm-svn: 23801

llvm-svn: 23797

removal of a bunch of ad-hoc and crufty code from SelectionDAG.cpp.

llvm-svn: 23682

the second phase of dag combining

llvm-svn: 23631

llvm-svn: 23579

Though I have done extensive testing, it is possible that this will break
things in configs I can't test.  Please let me know if this causes a problem
and I'll fix it ASAP.

llvm-svn: 23504

If the target prefers it, use _setjmp/_longjmp should be used instead of setjmp/longjmp for llvm.setjmp/llvm.longjmp.

llvm-svn: 23481

into particular vregs, emit copies into the entry MBB.

llvm-svn: 23331

that option for PowerPC's beta.

llvm-svn: 23253

number of elements.

llvm-svn: 23219

llvm-svn: 23215

instead of ZERO_EXTEND to eliminate extraneous extensions.  This eliminates
dead zero extensions on formal arguments and other cases on PPC, implementing
the newly tightened up test/Regression/CodeGen/PowerPC/small-arguments.ll test.

llvm-svn: 23205

llvm-svn: 23186

llvm-svn: 23114

changes the code generated for:

short %test(short %A) {
  %B = xor short %A, -32768
  ret short %B
}

to:

_test:
        xori r2, r3, 32768
        xoris r2, r2, 65535
        extsh r3, r2
        blr

instead of:

_test:
        rlwinm r2, r3, 0, 16, 31
        xori r2, r3, 32768
        xoris r2, r2, 65535
        extsh r3, r2
        blr

llvm-svn: 23109

flag is set on an instruction.

llvm-svn: 23098

the target isel crashes due to unimplemented features like calls :)

llvm-svn: 22997

promoted to the right type.  This fixes: IA64/2005-08-22-LegalizerCrash.ll

llvm-svn: 22969

llvm-svn: 22863

Nate noticed in yacr2 (and I know occurs in other places as well).

This is still rough, as the critical edge blocks are not intelligently placed
but is added to get some idea to see if this improves performance.

llvm-svn: 22825

llvm-svn: 22822

used to tack a register number onto the node.

Instead of doing this, make a new node, RegisterSDNode, which is a leaf
containing a register number.  These three operations just become normal
DAG nodes now, instead of requiring special handling.

Note that with this change, it is no longer correct to make illegal
CopyFromReg/CopyToReg nodes.  The legalizer will not touch them, and this
is bad, so don't do it. :)

llvm-svn: 22806

CC out of the SetCC operation, making SETCC a standard ternary operation and
CC's a standard DAG leaf.  This will make it possible for other node to use
CC's as operands in the future...

llvm-svn: 22728

llvm-svn: 22523

llvm-svn: 22469

1. Pass Value*'s into lowering methods so that the proper pointers can be
   added to load/stores from the valist
2. Intrinsics that return void should only return a token chain, not a token
   chain/retval pair.
3. Rename LowerVAArgNext -> LowerVAArg, because VANext is long gone.

llvm-svn: 22338

llvm-svn: 22315

tracking the instructions causing loads and stores provides more information than just the pointer being loaded or stored

llvm-svn: 22311

See last commit for LangRef, this implements it on all targets.

llvm-svn: 22273

llvm-svn: 22254

llvm-svn: 22026

llvm-svn: 22015

llvm-svn: 22004

llvm-svn: 21993

llvm-svn: 21958

llvm-svn: 21931

llvm-svn: 21930

llvm-svn: 21900