the testcases should be merged.

llvm-svn: 112711

int x(int t) {
  if (t & 256)
    return -26;
  return 0;
}

We generate this:

     tst.w   r0, #256
     mvn     r0, #25
     it      eq
     moveq   r0, #0

while gcc generates this:

     ands    r0, r0, #256
     it      ne
     mvnne   r0, #25
     bx      lr

Scandalous really!

During ISel time, we can look for this particular pattern. One where we have a
"MOVCC" that uses the flag off of a CMPZ that itself is comparing an AND
instruction to 0. Something like this (greatly simplified):

  %r0 = ISD::AND ...
  ARMISD::CMPZ %r0, 0         @ sets [CPSR]
  %r0 = ARMISD::MOVCC 0, -26  @ reads [CPSR]

All we have to do is convert the "ISD::AND" into an "ARM::ANDS" that sets [CPSR]
when it's zero. The zero value will all ready be in the %r0 register and we only
need to change it if the AND wasn't zero. Easy!

llvm-svn: 112664

is meant to do exactly the same thing. Thanks to Jim Grosbach for pointing this
out! :-)

llvm-svn: 112538

Make ARM add rN, sp, #imm instructions rematerializable. That's how the address of locals is calculated, so this should
help relieve register pressure a bit. Recalculating the local address is
almost always going to be better than spilling.

llvm-svn: 112503

optional modified register (instead of reg0). Along with r112461 it will make
sure that the optional define of CPSR is marked as "def" and will thus mark the
instructions using these classes (t2ANDS*) as setting the 's' flag.

llvm-svn: 112462

- Create T2I_bin_sw_irs to be like T2I_bin_w_irs, but that it sets the S bit.

llvm-svn: 112399

llvm-svn: 112395

it sets the CPSR register.

llvm-svn: 112393

encodable as a 16-bit wide instruction.

llvm-svn: 112195

llvm-svn: 112191

comparison with 0. These two pieces of code should give identical results:

  rsbs r1, r1, 0
  cmp  r0, r1
  mov  r0, #0
  it   ls
  mov  r0, #1

and:

  cmn  r0, r1
  mov  r0, #0
  it   ls
  mov  r0, #1

However, the CMN gives the *opposite* result when r1 is 0. This is because the
carry flag is set in the CMP case but not in the CMN case. In short, the CMP
instruction doesn't perform a truncate of the (logical) NOT of 0 plus the value
of r0 and the carry bit (because the "carry bit" parameter to AddWithCarry is
defined as 1 in this case, the carry flag will always be set when r0 >= 0). The
CMN instruction doesn't perform a NOT of 0 so there is never a "carry" when this
AddWithCarry is performed (because the "carry bit" parameter to AddWithCarry is
defined as 0).

The AddWithCarry in the CMP case seems to be relying upon the identity:

  ~x + 1 = -x

However when x is 0 and unsigned, this doesn't hold:

   x = 0
  ~x = 0xFFFF FFFF
  ~x + 1 = 0x1 0000 0000
  (-x = 0) != (0x1 0000 0000 = ~x + 1)

Therefore, we should disable *all* versions of CMN, especially when comparing
against zero, until we can limit when the CMN instruction is used (when we know
that the RHS is not 0) or when we have a hardware fix for this.

(See the ARM docs for the "AddWithCarry" pseudo-code.)

This is related to <rdar://problem/7569620>.

llvm-svn: 112176

llvm-svn: 111481

llvm-svn: 111277

llvm-svn: 111266

printing "lsl #0".  This fixes the remaining parts of pr7792.  Make
corresponding changes for encoding/decoding these instructions.

llvm-svn: 111251

that the high halfword is zero.  The shift need not be exactly 16 bits.

llvm-svn: 111196

instructions besides saturate instructions.  No functional changes.

llvm-svn: 111168

llvm-svn: 111068

This fixes another part of PR7792.

llvm-svn: 111057

instruction opcode.  This fixes part of PR7792.

llvm-svn: 111047

llvm-svn: 110787

  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: 110780

llvm-svn: 110745

llvm-svn: 110710

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

the jtblock_operand print methods.  This avoids extra newlines in the
disassembler's output.  PR7757.

llvm-svn: 109948

have 4 bits per register in the operand encoding), but have undefined
behavior when the operand value is 13 or 15 (SP and PC, respectively).
The trivial coalescer in linear scan sometimes will merge a copy from
SP into a subsequent instruction which uses the copy, and if that
instruction cannot legally reference SP, we get bad code such as:
  mls r0,r9,r0,sp
instead of:
  mov r2, sp
  mls r0, r9, r0, r2

This patch adds a new register class for use by Thumb2 that excludes
the problematic registers (SP and PC) and is used instead of GPR
for those operands which cannot legally reference PC or SP. The
trivial coalescer explicitly requires that the register class
of the destination for the COPY instruction contain the source
register for the COPY to be considered for coalescing. This prevents
errant instructions like that above.

PR7499

llvm-svn: 109842

llvm-svn: 109813

Add intrinsics __builtin_arm_qadd & __builtin_arm_qsub to allow access to the QADD & QSUB instructions.
Behave identically to __qadd & __qsub RealView instruction intrinsics.

llvm-svn: 109770

Remove incorrect substitution pattern for UXTB16. It wrongly assumed the input shift was actually a rotate. rdar://8240138

llvm-svn: 109693

instruction selection to prefer it when possible. rdar://7903972

llvm-svn: 108844

and a combine pattern to use it for setting a bit-field to a constant
value. More to come for non-constant stores.

llvm-svn: 108570

in the literal field of an instruction. E.g.,
long long foo(long long a) {
  return a - 734439407618LL;
}

rdar://7038284

llvm-svn: 108339

Patch by Brian Lucas. PR7636.

llvm-svn: 108332

llvm-svn: 107122

llvm-svn: 106770

being moved around away from the jump table it references. rdar://8104340

llvm-svn: 106483

- This fixed a number of bugs in if-converter, tail merging, and post-allocation
  scheduler. If-converter now runs branch folding / tail merging first to
  maximize if-conversion opportunities.
- Also changed the t2IT instruction slightly. It now defines the ITSTATE
  register which is read by instructions in the IT block.
- Added Thumb2 specific hazard recognizer to ensure the scheduler doesn't
  change the instruction ordering in the IT block (since IT mask has been
  finalized). It also ensures no other instructions can be scheduled between
  instructions in the IT block.

This is not yet enabled.

llvm-svn: 106344

llvm-svn: 105350