movw. That is we promote the destination operand to r16. So
        %CH = TRUNC_R16_R8 %BP
is emitted as
        movw %bp, %cx.

This is incorrect. If %cl is live, it would be clobbered.
Ideally we want to do the opposite, that is emitted it as
        movb ??, %ch
But this is not possible since %bp does not have a r8 sub-register.

We are now defining a new register class R16_ which is a subclass of R16
containing only those 16-bit registers that have r8 sub-registers (i.e.
AX - DX). We isel the truncate to two instructions, a MOV16to16_ to copy the
value to the R16_ class, followed by a TRUNC_R16_R8.

Due to bug 770, the register colaescer is not going to coalesce between R16 and
R16_. That will be fixed later so we can eliminate the MOV16to16_. Right now, it
can only be eliminated if we are lucky that source and destination registers are
the same.

llvm-svn: 28164

definition of the User class is available, this fixes the  build with some
compiler versions.

llvm-svn: 28163

llvm-svn: 28162

llvm-svn: 28161

llvm-svn: 28160

Change test to be a positive test instead of a negative test

llvm-svn: 28159

llvm-svn: 28158

Unlike Unix, Windows won't let a file be implicitly replaced via renaming without explicit permission.

llvm-svn: 28157

still a couple missed optimizations, but we now generate all the possible
rlwimis for multiple inserts into the same bitfield.  More regression tests
to come.

llvm-svn: 28156

to handle all kinds of stuff, including silly things like:
sextinreg(setcc,i16) -> setcc.

llvm-svn: 28155

llvm-svn: 28154

Apply bug fix supplied by Greg Pettyjohn for a bug he found:  '<invalid>' is not a legal path on Windows.

llvm-svn: 28153

llvm-svn: 28152

llvm-svn: 28151

llvm-svn: 28150

llvm-svn: 28149

llvm-svn: 28148

llvm-svn: 28147

sign_extend_inreg operations.  Though ComputeNumSignBits is still rudimentary,
this is enough to compile this:

short test(short X, short x) {
  int Y = X+x;
  return (Y >> 1);
}
short test2(short X, short x) {
  int Y = (short)(X+x);
  return Y >> 1;
}

into:

_test:
        add r2, r3, r4
        srawi r3, r2, 1
        blr
_test2:
        add r2, r3, r4
        extsh r2, r2
        srawi r3, r2, 1
        blr

instead of:

_test:
        add r2, r3, r4
        srawi r2, r2, 1
        extsh r3, r2
        blr
_test2:
        add r2, r3, r4
        extsh r2, r2
        srawi r2, r2, 1
        extsh r3, r2
        blr

llvm-svn: 28146

This will certainly be enhanced in the future.

llvm-svn: 28145

llvm-svn: 28144

a cast immediately before a PHI node.

This fixes Regression/CodeGen/Generic/2006-05-06-GEP-Cast-Sink-Crash.ll

llvm-svn: 28143

llvm-svn: 28142

Make the "fold (and (cast A), (cast B)) -> (cast (and A, B))" transformation
only apply when both casts really will cause code to be generated.  If one or
both doesn't, then this xform doesn't remove a cast.

This fixes Transforms/InstCombine/2006-05-06-Infloop.ll

llvm-svn: 28141

llvm-svn: 28140

llvm-svn: 28139

llvm-svn: 28138

27,28c27
<       movzwl %di, %edi
<       movl %edi, %ebx
---
>       movw %di, %bx

llvm-svn: 28137

llvm-svn: 28136

llvm-svn: 28135

using them.

llvm-svn: 28134

llvm-svn: 28133

llvm-svn: 28132

llvm-svn: 28131

llvm-svn: 28130

generated:

        movl 8(%esp), %eax
        movl %eax, %edx
        addl $4316, %edx
        cmpb $1, %cl
        ja LBB1_2       #cond_false
LBB1_1: #cond_true
        movl L_QuantizationTables720$non_lazy_ptr, %ecx
        movl %ecx, (%edx)
        movl L_QNOtoQuantTableShift720$non_lazy_ptr, %edx
        movl %edx, 4460(%eax)
        ret
...

Now we generate:

        movl 8(%esp), %eax
        cmpb $1, %cl
        ja LBB1_2       #cond_false
LBB1_1: #cond_true
        movl L_QuantizationTables720$non_lazy_ptr, %ecx
        movl %ecx, 4316(%eax)
        movl L_QNOtoQuantTableShift720$non_lazy_ptr, %ecx
        movl %ecx, 4460(%eax)
        ret

... which uses one fewer register.

llvm-svn: 28129

llvm-svn: 28128

llvm-svn: 28127

llvm-svn: 28126

llvm-svn: 28125