instruction opcode.  This also fixes part of PR7792.

llvm-svn: 110875

llvm-svn: 110810

float t1(int argc) {
  return (argc == 1123) ? 1.234f : 2.38213f;
}

We would generate truly awful code on ARM (those with a weak stomach should look
away):

_t1:
  movw   r1, #1123
  movs   r2, #1
  movs   r3, #0
  cmp    r0, r1
  mov.w  r0, #0
  it     eq
  moveq  r0, r2
  movs   r1, #4
  cmp    r0, #0
  it     ne
  movne  r3, r1
  adr    r0, #LCPI1_0
  ldr    r0, [r0, r3]
  bx     lr

The problem was that legalization was creating a cascade of SELECT_CC nodes, for
for the comparison of "argc == 1123" which was fed into a SELECT node for the ?:
statement which was itself converted to a SELECT_CC node. This is because the
ARM back-end doesn't have custom lowering for SELECT nodes, so it used the
default "Expand".

I added a fairly simple "LowerSELECT" to the ARM back-end. It takes care of this
testcase, but can obviously be expanded to include more cases.

Now we generate this, which looks optimal to me:

_t1:
  movw   r1, #1123
  movs   r2, #0
  cmp    r0, r1
  adr    r0, #LCPI0_0
  it     eq
  moveq  r2, #4
  ldr    r0, [r0, r2]
  bx     lr
  .align  2
LCPI0_0:
  .long   1075344593  @ float 2.382130e+00
  .long   1067316150  @ float 1.234000e+00

llvm-svn: 110799

Report error if codegen tries to instantiate a ARM target when the cpu does support it. e.g. cortex-m* processors.

llvm-svn: 110798

llvm-svn: 110797

llvm-svn: 110796

llvm-svn: 110795

MC/ARM: Add basic support for handling predication by parsing it out of the mnemonic into a separate operand form.

llvm-svn: 110794

llvm-svn: 110793

llvm-svn: 110792

llvm-svn: 110790

llvm-svn: 110788

llvm-svn: 110787

instructions: dmb, dsb, isb, msr, and mrs.

llvm-svn: 110786

  memory and synchronization barrier dmb and dsb instructions.
- Change instruction names to something more sensible (matching name of actual
  instructions).
- Added tests for memory barrier codegen.

llvm-svn: 110785

llvm-svn: 110783

llvm-svn: 110782

for some reason they have a very odd MCInst form where the operands overlap, but
I haven't dug in to find out why yet.

llvm-svn: 110781

llvm-svn: 110780

llvm-svn: 110762

llvm-svn: 110761

(I discovered 2 more copies of the ARM instruction format list, bringing the
total to 4!!  Two of them were already out of sync.  I haven't yet gotten into
the disassembler enough to know the best way to fix this, but something needs
to be done.)  Add support for encoding these instructions.

llvm-svn: 110754

llvm-svn: 110745

a register before checking if it was defined.

llvm-svn: 110733

llvm-svn: 110710

Re-apply r110655 with fixes. Epilogue must restore sp from fp if the function stack frame has a var-sized object.

Also added a test case to check for the added benefit of this patch: it's optimizing away the unnecessary restore of sp from fp for some non-leaf functions.

llvm-svn: 110707

register is", it breaks a couple test-suite tests.

llvm-svn: 110701

reserved, not available for general allocation. This eliminates all the
extra checks for Darwin.

This change also fixes the use of FP to access frame indices in leaf
functions and cleaned up some confusing code in epilogue emission.

llvm-svn: 110655

This will always be false before PEI:
(DisableFramePointerElim(MF) && MFI->adjustsStack())
Which means it's going to make r11 available as a general purpose register even
if -disable-fp-elim is specified. It's working on Darwin only because r7 is
always reserved. But it's obviously broken for other targets.

llvm-svn: 110614

llvm-svn: 110587

Change -prefer-32bit-thumb to attribute -mattr=+32bit instead to disable more 32-bit to 16-bit optimizations.

llvm-svn: 110584

llvm-svn: 110579

relatively expensive comparison analyzer on each instruction. Also rename the
comparison analyzer method to something more in line with what it actually does.

This pass is will eventually be folded into the Machine CSE pass.

llvm-svn: 110539

llvm-svn: 110460

Without this what was happening was:

* R3 is not marked as "used"
* ARM backend thinks it has to save it to the stack because of vaarg
* Offset computation correctly ignores it
* Offsets are wrong

llvm-svn: 110446

This pass tries to remove comparison instructions when possible. For instance,
if you have this code:

   sub r1, 1
   cmp r1, 0
   bz  L1

and "sub" either sets the same flag as the "cmp" instruction or could be
converted to set the same flag, then we can eliminate the "cmp" instruction all
together. This is a important for ARM where the ALU instructions could set the
CPSR flag, but need a special suffix ('s') to do so.

llvm-svn: 110423

llvm-svn: 110410

ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396

register for local access when it's closer to the stack slot being refererenced
than the stack pointer. Make sure to take into account any argument frame
SP adjustments that are in affect at the time.

rdar://8256090

llvm-svn: 110366

llvm-svn: 110363