LangRef.rst

return value is available.

Example:
""""""""

.. code-block:: llvm

      %retval = invoke i32 @Test(i32 15) to label %Continue
                  unwind label %TestCleanup              ; {i32}:retval set
      %retval = invoke coldcc i32 %Testfnptr(i32 15) to label %Continue
                  unwind label %TestCleanup              ; {i32}:retval set

.. _i_resume:

'``resume``' Instruction
^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      resume <type> <value>

Overview:
"""""""""

The '``resume``' instruction is a terminator instruction that has no
successors.

Arguments:
""""""""""

The '``resume``' instruction requires one argument, which must have the
same type as the result of any '``landingpad``' instruction in the same
function.

Semantics:
""""""""""

The '``resume``' instruction resumes propagation of an existing
(in-flight) exception whose unwinding was interrupted with a
:ref:`landingpad <i_landingpad>` instruction.

Example:
""""""""

.. code-block:: llvm

      resume { i8*, i32 } %exn

.. _i_unreachable:

'``unreachable``' Instruction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      unreachable

Overview:
"""""""""

The '``unreachable``' instruction has no defined semantics. This
instruction is used to inform the optimizer that a particular portion of
the code is not reachable. This can be used to indicate that the code
after a no-return function cannot be reached, and other facts.

Semantics:
""""""""""

The '``unreachable``' instruction has no defined semantics.

.. _binaryops:

Binary Operations
-----------------

Binary operators are used to do most of the computation in a program.
They require two operands of the same type, execute an operation on
them, and produce a single value. The operands might represent multiple
data, as is the case with the :ref:`vector <t_vector>` data type. The
result value has the same type as its operands.

There are several different binary operators:

.. _i_add:

'``add``' Instruction
^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = add <ty> <op1>, <op2>          ; yields {ty}:result
      <result> = add nuw <ty> <op1>, <op2>      ; yields {ty}:result
      <result> = add nsw <ty> <op1>, <op2>      ; yields {ty}:result
      <result> = add nuw nsw <ty> <op1>, <op2>  ; yields {ty}:result

Overview:
"""""""""

The '``add``' instruction returns the sum of its two operands.

Arguments:
""""""""""

The two arguments to the '``add``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The value produced is the integer sum of the two operands.

If the sum has unsigned overflow, the result returned is the
mathematical result modulo 2\ :sup:`n`\ , where n is the bit width of
the result.

Because LLVM integers use a two's complement representation, this
instruction is appropriate for both signed and unsigned integers.

``nuw`` and ``nsw`` stand for "No Unsigned Wrap" and "No Signed Wrap",
respectively. If the ``nuw`` and/or ``nsw`` keywords are present, the
result value of the ``add`` is a :ref:`poison value <poisonvalues>` if
unsigned and/or signed overflow, respectively, occurs.

Example:
""""""""

.. code-block:: llvm

      <result> = add i32 4, %var          ; yields {i32}:result = 4 + %var

.. _i_fadd:

'``fadd``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = fadd [fast-math flags]* <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``fadd``' instruction returns the sum of its two operands.

Arguments:
""""""""""

The two arguments to the '``fadd``' instruction must be :ref:`floating
point <t_floating>` or :ref:`vector <t_vector>` of floating point values.
Both arguments must have identical types.

Semantics:
""""""""""

The value produced is the floating point sum of the two operands. This
instruction can also take any number of :ref:`fast-math flags <fastmath>`,
which are optimization hints to enable otherwise unsafe floating point
optimizations:

Example:
""""""""

.. code-block:: llvm

      <result> = fadd float 4.0, %var          ; yields {float}:result = 4.0 + %var

'``sub``' Instruction
^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = sub <ty> <op1>, <op2>          ; yields {ty}:result
      <result> = sub nuw <ty> <op1>, <op2>      ; yields {ty}:result
      <result> = sub nsw <ty> <op1>, <op2>      ; yields {ty}:result
      <result> = sub nuw nsw <ty> <op1>, <op2>  ; yields {ty}:result

Overview:
"""""""""

The '``sub``' instruction returns the difference of its two operands.

Note that the '``sub``' instruction is used to represent the '``neg``'
instruction present in most other intermediate representations.

Arguments:
""""""""""

The two arguments to the '``sub``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The value produced is the integer difference of the two operands.

If the difference has unsigned overflow, the result returned is the
mathematical result modulo 2\ :sup:`n`\ , where n is the bit width of
the result.

Because LLVM integers use a two's complement representation, this
instruction is appropriate for both signed and unsigned integers.

``nuw`` and ``nsw`` stand for "No Unsigned Wrap" and "No Signed Wrap",
respectively. If the ``nuw`` and/or ``nsw`` keywords are present, the
result value of the ``sub`` is a :ref:`poison value <poisonvalues>` if
unsigned and/or signed overflow, respectively, occurs.

Example:
""""""""

.. code-block:: llvm

      <result> = sub i32 4, %var          ; yields {i32}:result = 4 - %var
      <result> = sub i32 0, %val          ; yields {i32}:result = -%var

.. _i_fsub:

'``fsub``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = fsub [fast-math flags]* <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``fsub``' instruction returns the difference of its two operands.

Note that the '``fsub``' instruction is used to represent the '``fneg``'
instruction present in most other intermediate representations.

Arguments:
""""""""""

The two arguments to the '``fsub``' instruction must be :ref:`floating
point <t_floating>` or :ref:`vector <t_vector>` of floating point values.
Both arguments must have identical types.

Semantics:
""""""""""

The value produced is the floating point difference of the two operands.
This instruction can also take any number of :ref:`fast-math
flags <fastmath>`, which are optimization hints to enable otherwise
unsafe floating point optimizations:

Example:
""""""""

.. code-block:: llvm

      <result> = fsub float 4.0, %var           ; yields {float}:result = 4.0 - %var
      <result> = fsub float -0.0, %val          ; yields {float}:result = -%var

'``mul``' Instruction
^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = mul <ty> <op1>, <op2>          ; yields {ty}:result
      <result> = mul nuw <ty> <op1>, <op2>      ; yields {ty}:result
      <result> = mul nsw <ty> <op1>, <op2>      ; yields {ty}:result
      <result> = mul nuw nsw <ty> <op1>, <op2>  ; yields {ty}:result

Overview:
"""""""""

The '``mul``' instruction returns the product of its two operands.

Arguments:
""""""""""

The two arguments to the '``mul``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The value produced is the integer product of the two operands.

If the result of the multiplication has unsigned overflow, the result
returned is the mathematical result modulo 2\ :sup:`n`\ , where n is the
bit width of the result.

Because LLVM integers use a two's complement representation, and the
result is the same width as the operands, this instruction returns the
correct result for both signed and unsigned integers. If a full product
(e.g. ``i32`` * ``i32`` -> ``i64``) is needed, the operands should be
sign-extended or zero-extended as appropriate to the width of the full
product.

``nuw`` and ``nsw`` stand for "No Unsigned Wrap" and "No Signed Wrap",
respectively. If the ``nuw`` and/or ``nsw`` keywords are present, the
result value of the ``mul`` is a :ref:`poison value <poisonvalues>` if
unsigned and/or signed overflow, respectively, occurs.

Example:
""""""""

.. code-block:: llvm

      <result> = mul i32 4, %var          ; yields {i32}:result = 4 * %var

.. _i_fmul:

'``fmul``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = fmul [fast-math flags]* <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``fmul``' instruction returns the product of its two operands.

Arguments:
""""""""""

The two arguments to the '``fmul``' instruction must be :ref:`floating
point <t_floating>` or :ref:`vector <t_vector>` of floating point values.
Both arguments must have identical types.

Semantics:
""""""""""

The value produced is the floating point product of the two operands.
This instruction can also take any number of :ref:`fast-math
flags <fastmath>`, which are optimization hints to enable otherwise
unsafe floating point optimizations:

Example:
""""""""

.. code-block:: llvm

      <result> = fmul float 4.0, %var          ; yields {float}:result = 4.0 * %var

'``udiv``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = udiv <ty> <op1>, <op2>         ; yields {ty}:result
      <result> = udiv exact <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``udiv``' instruction returns the quotient of its two operands.

Arguments:
""""""""""

The two arguments to the '``udiv``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The value produced is the unsigned integer quotient of the two operands.

Note that unsigned integer division and signed integer division are
distinct operations; for signed integer division, use '``sdiv``'.

Division by zero leads to undefined behavior.

If the ``exact`` keyword is present, the result value of the ``udiv`` is
a :ref:`poison value <poisonvalues>` if %op1 is not a multiple of %op2 (as
such, "((a udiv exact b) mul b) == a").

Example:
""""""""

.. code-block:: llvm

      <result> = udiv i32 4, %var          ; yields {i32}:result = 4 / %var

'``sdiv``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = sdiv <ty> <op1>, <op2>         ; yields {ty}:result
      <result> = sdiv exact <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``sdiv``' instruction returns the quotient of its two operands.

Arguments:
""""""""""

The two arguments to the '``sdiv``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The value produced is the signed integer quotient of the two operands
rounded towards zero.

Note that signed integer division and unsigned integer division are
distinct operations; for unsigned integer division, use '``udiv``'.

Division by zero leads to undefined behavior. Overflow also leads to
undefined behavior; this is a rare case, but can occur, for example, by
doing a 32-bit division of -2147483648 by -1.

If the ``exact`` keyword is present, the result value of the ``sdiv`` is
a :ref:`poison value <poisonvalues>` if the result would be rounded.

Example:
""""""""

.. code-block:: llvm

      <result> = sdiv i32 4, %var          ; yields {i32}:result = 4 / %var

.. _i_fdiv:

'``fdiv``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = fdiv [fast-math flags]* <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``fdiv``' instruction returns the quotient of its two operands.

Arguments:
""""""""""

The two arguments to the '``fdiv``' instruction must be :ref:`floating
point <t_floating>` or :ref:`vector <t_vector>` of floating point values.
Both arguments must have identical types.

Semantics:
""""""""""

The value produced is the floating point quotient of the two operands.
This instruction can also take any number of :ref:`fast-math
flags <fastmath>`, which are optimization hints to enable otherwise
unsafe floating point optimizations:

Example:
""""""""

.. code-block:: llvm

      <result> = fdiv float 4.0, %var          ; yields {float}:result = 4.0 / %var

'``urem``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = urem <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``urem``' instruction returns the remainder from the unsigned
division of its two arguments.

Arguments:
""""""""""

The two arguments to the '``urem``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

This instruction returns the unsigned integer *remainder* of a division.
This instruction always performs an unsigned division to get the
remainder.

Note that unsigned integer remainder and signed integer remainder are
distinct operations; for signed integer remainder, use '``srem``'.

Taking the remainder of a division by zero leads to undefined behavior.

Example:
""""""""

.. code-block:: llvm

      <result> = urem i32 4, %var          ; yields {i32}:result = 4 % %var

'``srem``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = srem <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``srem``' instruction returns the remainder from the signed
division of its two operands. This instruction can also take
:ref:`vector <t_vector>` versions of the values in which case the elements
must be integers.

Arguments:
""""""""""

The two arguments to the '``srem``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

This instruction returns the *remainder* of a division (where the result
is either zero or has the same sign as the dividend, ``op1``), not the
*modulo* operator (where the result is either zero or has the same sign
as the divisor, ``op2``) of a value. For more information about the
difference, see `The Math
Forum <http://mathforum.org/dr.math/problems/anne.4.28.99.html>`_. For a
table of how this is implemented in various languages, please see
`Wikipedia: modulo
operation <http://en.wikipedia.org/wiki/Modulo_operation>`_.

Note that signed integer remainder and unsigned integer remainder are
distinct operations; for unsigned integer remainder, use '``urem``'.

Taking the remainder of a division by zero leads to undefined behavior.
Overflow also leads to undefined behavior; this is a rare case, but can
occur, for example, by taking the remainder of a 32-bit division of
-2147483648 by -1. (The remainder doesn't actually overflow, but this
rule lets srem be implemented using instructions that return both the
result of the division and the remainder.)

Example:
""""""""

.. code-block:: llvm

      <result> = srem i32 4, %var          ; yields {i32}:result = 4 % %var

.. _i_frem:

'``frem``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = frem [fast-math flags]* <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``frem``' instruction returns the remainder from the division of
its two operands.

Arguments:
""""""""""

The two arguments to the '``frem``' instruction must be :ref:`floating
point <t_floating>` or :ref:`vector <t_vector>` of floating point values.
Both arguments must have identical types.

Semantics:
""""""""""

This instruction returns the *remainder* of a division. The remainder
has the same sign as the dividend. This instruction can also take any
number of :ref:`fast-math flags <fastmath>`, which are optimization hints
to enable otherwise unsafe floating point optimizations:

Example:
""""""""

.. code-block:: llvm

      <result> = frem float 4.0, %var          ; yields {float}:result = 4.0 % %var

.. _bitwiseops:

Bitwise Binary Operations
-------------------------

Bitwise binary operators are used to do various forms of bit-twiddling
in a program. They are generally very efficient instructions and can
commonly be strength reduced from other instructions. They require two
operands of the same type, execute an operation on them, and produce a
single value. The resulting value is the same type as its operands.

'``shl``' Instruction
^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = shl <ty> <op1>, <op2>           ; yields {ty}:result
      <result> = shl nuw <ty> <op1>, <op2>       ; yields {ty}:result
      <result> = shl nsw <ty> <op1>, <op2>       ; yields {ty}:result
      <result> = shl nuw nsw <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``shl``' instruction returns the first operand shifted to the left
a specified number of bits.

Arguments:
""""""""""

Both arguments to the '``shl``' instruction must be the same
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer type.
'``op2``' is treated as an unsigned value.

Semantics:
""""""""""

The value produced is ``op1`` \* 2\ :sup:`op2` mod 2\ :sup:`n`,
where ``n`` is the width of the result. If ``op2`` is (statically or
dynamically) negative or equal to or larger than the number of bits in
``op1``, the result is undefined. If the arguments are vectors, each
vector element of ``op1`` is shifted by the corresponding shift amount
in ``op2``.

If the ``nuw`` keyword is present, then the shift produces a :ref:`poison
value <poisonvalues>` if it shifts out any non-zero bits. If the
``nsw`` keyword is present, then the shift produces a :ref:`poison
value <poisonvalues>` if it shifts out any bits that disagree with the
resultant sign bit. As such, NUW/NSW have the same semantics as they
would if the shift were expressed as a mul instruction with the same
nsw/nuw bits in (mul %op1, (shl 1, %op2)).

Example:
""""""""

.. code-block:: llvm

      <result> = shl i32 4, %var   ; yields {i32}: 4 << %var
      <result> = shl i32 4, 2      ; yields {i32}: 16
      <result> = shl i32 1, 10     ; yields {i32}: 1024
      <result> = shl i32 1, 32     ; undefined
      <result> = shl <2 x i32> < i32 1, i32 1>, < i32 1, i32 2>   ; yields: result=<2 x i32> < i32 2, i32 4>

'``lshr``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = lshr <ty> <op1>, <op2>         ; yields {ty}:result
      <result> = lshr exact <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``lshr``' instruction (logical shift right) returns the first
operand shifted to the right a specified number of bits with zero fill.

Arguments:
""""""""""

Both arguments to the '``lshr``' instruction must be the same
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer type.
'``op2``' is treated as an unsigned value.

Semantics:
""""""""""

This instruction always performs a logical shift right operation. The
most significant bits of the result will be filled with zero bits after
the shift. If ``op2`` is (statically or dynamically) equal to or larger
than the number of bits in ``op1``, the result is undefined. If the
arguments are vectors, each vector element of ``op1`` is shifted by the
corresponding shift amount in ``op2``.

If the ``exact`` keyword is present, the result value of the ``lshr`` is
a :ref:`poison value <poisonvalues>` if any of the bits shifted out are
non-zero.

Example:
""""""""

.. code-block:: llvm

      <result> = lshr i32 4, 1   ; yields {i32}:result = 2
      <result> = lshr i32 4, 2   ; yields {i32}:result = 1
      <result> = lshr i8  4, 3   ; yields {i8}:result = 0
      <result> = lshr i8 -2, 1   ; yields {i8}:result = 0x7FFFFFFF 
      <result> = lshr i32 1, 32  ; undefined
      <result> = lshr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 2>   ; yields: result=<2 x i32> < i32 0x7FFFFFFF, i32 1>

'``ashr``' Instruction
^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = ashr <ty> <op1>, <op2>         ; yields {ty}:result
      <result> = ashr exact <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``ashr``' instruction (arithmetic shift right) returns the first
operand shifted to the right a specified number of bits with sign
extension.

Arguments:
""""""""""

Both arguments to the '``ashr``' instruction must be the same
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer type.
'``op2``' is treated as an unsigned value.

Semantics:
""""""""""

This instruction always performs an arithmetic shift right operation,
The most significant bits of the result will be filled with the sign bit
of ``op1``. If ``op2`` is (statically or dynamically) equal to or larger
than the number of bits in ``op1``, the result is undefined. If the
arguments are vectors, each vector element of ``op1`` is shifted by the
corresponding shift amount in ``op2``.

If the ``exact`` keyword is present, the result value of the ``ashr`` is
a :ref:`poison value <poisonvalues>` if any of the bits shifted out are
non-zero.

Example:
""""""""

.. code-block:: llvm

      <result> = ashr i32 4, 1   ; yields {i32}:result = 2
      <result> = ashr i32 4, 2   ; yields {i32}:result = 1
      <result> = ashr i8  4, 3   ; yields {i8}:result = 0
      <result> = ashr i8 -2, 1   ; yields {i8}:result = -1
      <result> = ashr i32 1, 32  ; undefined
      <result> = ashr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 3>   ; yields: result=<2 x i32> < i32 -1, i32 0>

'``and``' Instruction
^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = and <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``and``' instruction returns the bitwise logical and of its two
operands.

Arguments:
""""""""""

The two arguments to the '``and``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The truth table used for the '``and``' instruction is:

+-----+-----+-----+
| In0 | In1 | Out |
+-----+-----+-----+
|   0 |   0 |   0 |
+-----+-----+-----+
|   0 |   1 |   0 |
+-----+-----+-----+
|   1 |   0 |   0 |
+-----+-----+-----+
|   1 |   1 |   1 |
+-----+-----+-----+

Example:
""""""""

.. code-block:: llvm

      <result> = and i32 4, %var         ; yields {i32}:result = 4 & %var
      <result> = and i32 15, 40          ; yields {i32}:result = 8
      <result> = and i32 4, 8            ; yields {i32}:result = 0

'``or``' Instruction
^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = or <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``or``' instruction returns the bitwise logical inclusive or of its
two operands.

Arguments:
""""""""""

The two arguments to the '``or``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The truth table used for the '``or``' instruction is:

+-----+-----+-----+
| In0 | In1 | Out |
+-----+-----+-----+
|   0 |   0 |   0 |
+-----+-----+-----+
|   0 |   1 |   1 |
+-----+-----+-----+
|   1 |   0 |   1 |
+-----+-----+-----+
|   1 |   1 |   1 |
+-----+-----+-----+

Example:
""""""""

::

      <result> = or i32 4, %var         ; yields {i32}:result = 4 | %var
      <result> = or i32 15, 40          ; yields {i32}:result = 47
      <result> = or i32 4, 8            ; yields {i32}:result = 12

'``xor``' Instruction
^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = xor <ty> <op1>, <op2>   ; yields {ty}:result

Overview:
"""""""""

The '``xor``' instruction returns the bitwise logical exclusive or of
its two operands. The ``xor`` is used to implement the "one's
complement" operation, which is the "~" operator in C.

Arguments:
""""""""""

The two arguments to the '``xor``' instruction must be
:ref:`integer <t_integer>` or :ref:`vector <t_vector>` of integer values. Both
arguments must have identical types.

Semantics:
""""""""""

The truth table used for the '``xor``' instruction is:

+-----+-----+-----+
| In0 | In1 | Out |
+-----+-----+-----+
|   0 |   0 |   0 |
+-----+-----+-----+
|   0 |   1 |   1 |
+-----+-----+-----+
|   1 |   0 |   1 |
+-----+-----+-----+
|   1 |   1 |   0 |
+-----+-----+-----+

Example:
""""""""

.. code-block:: llvm

      <result> = xor i32 4, %var         ; yields {i32}:result = 4 ^ %var
      <result> = xor i32 15, 40          ; yields {i32}:result = 39
      <result> = xor i32 4, 8            ; yields {i32}:result = 12
      <result> = xor i32 %V, -1          ; yields {i32}:result = ~%V

Vector Operations
-----------------

LLVM supports several instructions to represent vector operations in a
target-independent manner. These instructions cover the element-access
and vector-specific operations needed to process vectors effectively.
While LLVM does directly support these vector operations, many
sophisticated algorithms will want to use target-specific intrinsics to
take full advantage of a specific target.

.. _i_extractelement:

'``extractelement``' Instruction
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      <result> = extractelement <n x <ty>> <val>, i32 <idx>    ; yields <ty>

Overview:
"""""""""

The '``extractelement``' instruction extracts a single scalar element
from a vector at a specified index.

Arguments:
""""""""""

The first operand of an '``extractelement``' instruction is a value of
:ref:`vector <t_vector>` type. The second operand is an index indicating
the position from which to extract the element. The index may be a
variable.

Semantics:
""""""""""

The result is a scalar of the same type as the element type of ``val``.
Its value is the value at position ``idx`` of ``val``. If ``idx``
exceeds the length of ``val``, the results are undefined.

Example:
""""""""

.. code-block:: llvm

      <result> = extractelement <4 x i32> %vec, i32 0    ; yields i32

.. _i_insertelement: