LangRef.rst

      declare void %llvm.va_start(i8* <arglist>)

Overview:
"""""""""

The '``llvm.va_start``' intrinsic initializes ``*<arglist>`` for
subsequent use by ``va_arg``.

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

The argument is a pointer to a ``va_list`` element to initialize.

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

The '``llvm.va_start``' intrinsic works just like the ``va_start`` macro
available in C. In a target-dependent way, it initializes the
``va_list`` element to which the argument points, so that the next call
to ``va_arg`` will produce the first variable argument passed to the
function. Unlike the C ``va_start`` macro, this intrinsic does not need
to know the last argument of the function as the compiler can figure
that out.

'``llvm.va_end``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.va_end(i8* <arglist>)

Overview:
"""""""""

The '``llvm.va_end``' intrinsic destroys ``*<arglist>``, which has been
initialized previously with ``llvm.va_start`` or ``llvm.va_copy``.

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

The argument is a pointer to a ``va_list`` to destroy.

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

The '``llvm.va_end``' intrinsic works just like the ``va_end`` macro
available in C. In a target-dependent way, it destroys the ``va_list``
element to which the argument points. Calls to
:ref:`llvm.va_start <int_va_start>` and
:ref:`llvm.va_copy <int_va_copy>` must be matched exactly with calls to
``llvm.va_end``.

.. _int_va_copy:

'``llvm.va_copy``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)

Overview:
"""""""""

The '``llvm.va_copy``' intrinsic copies the current argument position
from the source argument list to the destination argument list.

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

The first argument is a pointer to a ``va_list`` element to initialize.
The second argument is a pointer to a ``va_list`` element to copy from.

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

The '``llvm.va_copy``' intrinsic works just like the ``va_copy`` macro
available in C. In a target-dependent way, it copies the source
``va_list`` element into the destination ``va_list`` element. This
intrinsic is necessary because the `` llvm.va_start`` intrinsic may be
arbitrarily complex and require, for example, memory allocation.

Accurate Garbage Collection Intrinsics
--------------------------------------

LLVM support for `Accurate Garbage Collection <GarbageCollection.html>`_
(GC) requires the implementation and generation of these intrinsics.
These intrinsics allow identification of :ref:`GC roots on the
stack <int_gcroot>`, as well as garbage collector implementations that
require :ref:`read <int_gcread>` and :ref:`write <int_gcwrite>` barriers.
Front-ends for type-safe garbage collected languages should generate
these intrinsics to make use of the LLVM garbage collectors. For more
details, see `Accurate Garbage Collection with
LLVM <GarbageCollection.html>`_.

The garbage collection intrinsics only operate on objects in the generic
address space (address space zero).

.. _int_gcroot:

'``llvm.gcroot``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)

Overview:
"""""""""

The '``llvm.gcroot``' intrinsic declares the existence of a GC root to
the code generator, and allows some metadata to be associated with it.

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

The first argument specifies the address of a stack object that contains
the root pointer. The second pointer (which must be either a constant or
a global value address) contains the meta-data to be associated with the
root.

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

At runtime, a call to this intrinsic stores a null pointer into the
"ptrloc" location. At compile-time, the code generator generates
information to allow the runtime to find the pointer at GC safe points.
The '``llvm.gcroot``' intrinsic may only be used in a function which
:ref:`specifies a GC algorithm <gc>`.

.. _int_gcread:

'``llvm.gcread``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)

Overview:
"""""""""

The '``llvm.gcread``' intrinsic identifies reads of references from heap
locations, allowing garbage collector implementations that require read
barriers.

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

The second argument is the address to read from, which should be an
address allocated from the garbage collector. The first object is a
pointer to the start of the referenced object, if needed by the language
runtime (otherwise null).

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

The '``llvm.gcread``' intrinsic has the same semantics as a load
instruction, but may be replaced with substantially more complex code by
the garbage collector runtime, as needed. The '``llvm.gcread``'
intrinsic may only be used in a function which :ref:`specifies a GC
algorithm <gc>`.

.. _int_gcwrite:

'``llvm.gcwrite``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)

Overview:
"""""""""

The '``llvm.gcwrite``' intrinsic identifies writes of references to heap
locations, allowing garbage collector implementations that require write
barriers (such as generational or reference counting collectors).

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

The first argument is the reference to store, the second is the start of
the object to store it to, and the third is the address of the field of
Obj to store to. If the runtime does not require a pointer to the
object, Obj may be null.

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

The '``llvm.gcwrite``' intrinsic has the same semantics as a store
instruction, but may be replaced with substantially more complex code by
the garbage collector runtime, as needed. The '``llvm.gcwrite``'
intrinsic may only be used in a function which :ref:`specifies a GC
algorithm <gc>`.

Code Generator Intrinsics
-------------------------

These intrinsics are provided by LLVM to expose special features that
may only be implemented with code generator support.

'``llvm.returnaddress``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare i8  *@llvm.returnaddress(i32 <level>)

Overview:
"""""""""

The '``llvm.returnaddress``' intrinsic attempts to compute a
target-specific value indicating the return address of the current
function or one of its callers.

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

The argument to this intrinsic indicates which function to return the
address for. Zero indicates the calling function, one indicates its
caller, etc. The argument is **required** to be a constant integer
value.

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

The '``llvm.returnaddress``' intrinsic either returns a pointer
indicating the return address of the specified call frame, or zero if it
cannot be identified. The value returned by this intrinsic is likely to
be incorrect or 0 for arguments other than zero, so it should only be
used for debugging purposes.

Note that calling this intrinsic does not prevent function inlining or
other aggressive transformations, so the value returned may not be that
of the obvious source-language caller.

'``llvm.frameaddress``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare i8* @llvm.frameaddress(i32 <level>)

Overview:
"""""""""

The '``llvm.frameaddress``' intrinsic attempts to return the
target-specific frame pointer value for the specified stack frame.

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

The argument to this intrinsic indicates which function to return the
frame pointer for. Zero indicates the calling function, one indicates
its caller, etc. The argument is **required** to be a constant integer
value.

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

The '``llvm.frameaddress``' intrinsic either returns a pointer
indicating the frame address of the specified call frame, or zero if it
cannot be identified. The value returned by this intrinsic is likely to
be incorrect or 0 for arguments other than zero, so it should only be
used for debugging purposes.

Note that calling this intrinsic does not prevent function inlining or
other aggressive transformations, so the value returned may not be that
of the obvious source-language caller.

.. _int_stacksave:

'``llvm.stacksave``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare i8* @llvm.stacksave()

Overview:
"""""""""

The '``llvm.stacksave``' intrinsic is used to remember the current state
of the function stack, for use with
:ref:`llvm.stackrestore <int_stackrestore>`. This is useful for
implementing language features like scoped automatic variable sized
arrays in C99.

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

This intrinsic returns a opaque pointer value that can be passed to
:ref:`llvm.stackrestore <int_stackrestore>`. When an
``llvm.stackrestore`` intrinsic is executed with a value saved from
``llvm.stacksave``, it effectively restores the state of the stack to
the state it was in when the ``llvm.stacksave`` intrinsic executed. In
practice, this pops any :ref:`alloca <i_alloca>` blocks from the stack that
were allocated after the ``llvm.stacksave`` was executed.

.. _int_stackrestore:

'``llvm.stackrestore``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.stackrestore(i8* %ptr)

Overview:
"""""""""

The '``llvm.stackrestore``' intrinsic is used to restore the state of
the function stack to the state it was in when the corresponding
:ref:`llvm.stacksave <int_stacksave>` intrinsic executed. This is
useful for implementing language features like scoped automatic variable
sized arrays in C99.

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

See the description for :ref:`llvm.stacksave <int_stacksave>`.

'``llvm.prefetch``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>, i32 <cache type>)

Overview:
"""""""""

The '``llvm.prefetch``' intrinsic is a hint to the code generator to
insert a prefetch instruction if supported; otherwise, it is a noop.
Prefetches have no effect on the behavior of the program but can change
its performance characteristics.

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

``address`` is the address to be prefetched, ``rw`` is the specifier
determining if the fetch should be for a read (0) or write (1), and
``locality`` is a temporal locality specifier ranging from (0) - no
locality, to (3) - extremely local keep in cache. The ``cache type``
specifies whether the prefetch is performed on the data (1) or
instruction (0) cache. The ``rw``, ``locality`` and ``cache type``
arguments must be constant integers.

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

This intrinsic does not modify the behavior of the program. In
particular, prefetches cannot trap and do not produce a value. On
targets that support this intrinsic, the prefetch can provide hints to
the processor cache for better performance.

'``llvm.pcmarker``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare void @llvm.pcmarker(i32 <id>)

Overview:
"""""""""

The '``llvm.pcmarker``' intrinsic is a method to export a Program
Counter (PC) in a region of code to simulators and other tools. The
method is target specific, but it is expected that the marker will use
exported symbols to transmit the PC of the marker. The marker makes no
guarantees that it will remain with any specific instruction after
optimizations. It is possible that the presence of a marker will inhibit
optimizations. The intended use is to be inserted after optimizations to
allow correlations of simulation runs.

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

``id`` is a numerical id identifying the marker.

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

This intrinsic does not modify the behavior of the program. Backends
that do not support this intrinsic may ignore it.

'``llvm.readcyclecounter``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

::

      declare i64 @llvm.readcyclecounter()

Overview:
"""""""""

The '``llvm.readcyclecounter``' intrinsic provides access to the cycle
counter register (or similar low latency, high accuracy clocks) on those
targets that support it. On X86, it should map to RDTSC. On Alpha, it
should map to RPCC. As the backing counters overflow quickly (on the
order of 9 seconds on alpha), this should only be used for small
timings.

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

When directly supported, reading the cycle counter should not modify any
memory. Implementations are allowed to either return a application
specific value or a system wide value. On backends without support, this
is lowered to a constant 0.

Standard C Library Intrinsics
-----------------------------

LLVM provides intrinsics for a few important standard C library
functions. These intrinsics allow source-language front-ends to pass
information about the alignment of the pointer arguments to the code
generator, providing opportunity for more efficient code generation.

.. _int_memcpy:

'``llvm.memcpy``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.memcpy`` on any
integer bit width and for different address spaces. Not all targets
support all bit widths however.

::

      declare void @llvm.memcpy.p0i8.p0i8.i32(i8* <dest>, i8* <src>,
                                              i32 <len>, i32 <align>, i1 <isvolatile>)
      declare void @llvm.memcpy.p0i8.p0i8.i64(i8* <dest>, i8* <src>,
                                              i64 <len>, i32 <align>, i1 <isvolatile>)

Overview:
"""""""""

The '``llvm.memcpy.*``' intrinsics copy a block of memory from the
source location to the destination location.

Note that, unlike the standard libc function, the ``llvm.memcpy.*``
intrinsics do not return a value, takes extra alignment/isvolatile
arguments and the pointers can be in specified address spaces.

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

The first argument is a pointer to the destination, the second is a
pointer to the source. The third argument is an integer argument
specifying the number of bytes to copy, the fourth argument is the
alignment of the source and destination locations, and the fifth is a
boolean indicating a volatile access.

If the call to this intrinsic has an alignment value that is not 0 or 1,
then the caller guarantees that both the source and destination pointers
are aligned to that boundary.

If the ``isvolatile`` parameter is ``true``, the ``llvm.memcpy`` call is
a :ref:`volatile operation <volatile>`. The detailed access behavior is not
very cleanly specified and it is unwise to depend on it.

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

The '``llvm.memcpy.*``' intrinsics copy a block of memory from the
source location to the destination location, which are not allowed to
overlap. It copies "len" bytes of memory over. If the argument is known
to be aligned to some boundary, this can be specified as the fourth
argument, otherwise it should be set to 0 or 1.

'``llvm.memmove``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use llvm.memmove on any integer
bit width and for different address space. Not all targets support all
bit widths however.

::

      declare void @llvm.memmove.p0i8.p0i8.i32(i8* <dest>, i8* <src>,
                                               i32 <len>, i32 <align>, i1 <isvolatile>)
      declare void @llvm.memmove.p0i8.p0i8.i64(i8* <dest>, i8* <src>,
                                               i64 <len>, i32 <align>, i1 <isvolatile>)

Overview:
"""""""""

The '``llvm.memmove.*``' intrinsics move a block of memory from the
source location to the destination location. It is similar to the
'``llvm.memcpy``' intrinsic but allows the two memory locations to
overlap.

Note that, unlike the standard libc function, the ``llvm.memmove.*``
intrinsics do not return a value, takes extra alignment/isvolatile
arguments and the pointers can be in specified address spaces.

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

The first argument is a pointer to the destination, the second is a
pointer to the source. The third argument is an integer argument
specifying the number of bytes to copy, the fourth argument is the
alignment of the source and destination locations, and the fifth is a
boolean indicating a volatile access.

If the call to this intrinsic has an alignment value that is not 0 or 1,
then the caller guarantees that the source and destination pointers are
aligned to that boundary.

If the ``isvolatile`` parameter is ``true``, the ``llvm.memmove`` call
is a :ref:`volatile operation <volatile>`. The detailed access behavior is
not very cleanly specified and it is unwise to depend on it.

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

The '``llvm.memmove.*``' intrinsics copy a block of memory from the
source location to the destination location, which may overlap. It
copies "len" bytes of memory over. If the argument is known to be
aligned to some boundary, this can be specified as the fourth argument,
otherwise it should be set to 0 or 1.

'``llvm.memset.*``' Intrinsics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use llvm.memset on any integer
bit width and for different address spaces. However, not all targets
support all bit widths.

::

      declare void @llvm.memset.p0i8.i32(i8* <dest>, i8 <val>,
                                         i32 <len>, i32 <align>, i1 <isvolatile>)
      declare void @llvm.memset.p0i8.i64(i8* <dest>, i8 <val>,
                                         i64 <len>, i32 <align>, i1 <isvolatile>)

Overview:
"""""""""

The '``llvm.memset.*``' intrinsics fill a block of memory with a
particular byte value.

Note that, unlike the standard libc function, the ``llvm.memset``
intrinsic does not return a value and takes extra alignment/volatile
arguments. Also, the destination can be in an arbitrary address space.

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

The first argument is a pointer to the destination to fill, the second
is the byte value with which to fill it, the third argument is an
integer argument specifying the number of bytes to fill, and the fourth
argument is the known alignment of the destination location.

If the call to this intrinsic has an alignment value that is not 0 or 1,
then the caller guarantees that the destination pointer is aligned to
that boundary.

If the ``isvolatile`` parameter is ``true``, the ``llvm.memset`` call is
a :ref:`volatile operation <volatile>`. The detailed access behavior is not
very cleanly specified and it is unwise to depend on it.

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

The '``llvm.memset.*``' intrinsics fill "len" bytes of memory starting
at the destination location. If the argument is known to be aligned to
some boundary, this can be specified as the fourth argument, otherwise
it should be set to 0 or 1.

'``llvm.sqrt.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.sqrt`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.sqrt.f32(float %Val)
      declare double    @llvm.sqrt.f64(double %Val)
      declare x86_fp80  @llvm.sqrt.f80(x86_fp80 %Val)
      declare fp128     @llvm.sqrt.f128(fp128 %Val)
      declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)

Overview:
"""""""""

The '``llvm.sqrt``' intrinsics return the sqrt of the specified operand,
returning the same value as the libm '``sqrt``' functions would. Unlike
``sqrt`` in libm, however, ``llvm.sqrt`` has undefined behavior for
negative numbers other than -0.0 (which allows for better optimization,
because there is no need to worry about errno being set).
``llvm.sqrt(-0.0)`` is defined to return -0.0 like IEEE sqrt.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the sqrt of the specified operand if it is a
nonnegative floating point number.

'``llvm.powi.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.powi`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.powi.f32(float  %Val, i32 %power)
      declare double    @llvm.powi.f64(double %Val, i32 %power)
      declare x86_fp80  @llvm.powi.f80(x86_fp80  %Val, i32 %power)
      declare fp128     @llvm.powi.f128(fp128 %Val, i32 %power)
      declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128  %Val, i32 %power)

Overview:
"""""""""

The '``llvm.powi.*``' intrinsics return the first operand raised to the
specified (positive or negative) power. The order of evaluation of
multiplications is not defined. When a vector of floating point type is
used, the second argument remains a scalar integer value.

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

The second argument is an integer power, and the first is a value to
raise to that power.

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

This function returns the first value raised to the second power with an
unspecified sequence of rounding operations.

'``llvm.sin.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.sin`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.sin.f32(float  %Val)
      declare double    @llvm.sin.f64(double %Val)
      declare x86_fp80  @llvm.sin.f80(x86_fp80  %Val)
      declare fp128     @llvm.sin.f128(fp128 %Val)
      declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.sin.*``' intrinsics return the sine of the operand.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the sine of the specified operand, returning the
same values as the libm ``sin`` functions would, and handles error
conditions in the same way.

'``llvm.cos.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.cos`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.cos.f32(float  %Val)
      declare double    @llvm.cos.f64(double %Val)
      declare x86_fp80  @llvm.cos.f80(x86_fp80  %Val)
      declare fp128     @llvm.cos.f128(fp128 %Val)
      declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.cos.*``' intrinsics return the cosine of the operand.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the cosine of the specified operand, returning the
same values as the libm ``cos`` functions would, and handles error
conditions in the same way.

'``llvm.pow.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.pow`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.pow.f32(float  %Val, float %Power)
      declare double    @llvm.pow.f64(double %Val, double %Power)
      declare x86_fp80  @llvm.pow.f80(x86_fp80  %Val, x86_fp80 %Power)
      declare fp128     @llvm.pow.f128(fp128 %Val, fp128 %Power)
      declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128  %Val, ppc_fp128 Power)

Overview:
"""""""""

The '``llvm.pow.*``' intrinsics return the first operand raised to the
specified (positive or negative) power.

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

The second argument is a floating point power, and the first is a value
to raise to that power.

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

This function returns the first value raised to the second power,
returning the same values as the libm ``pow`` functions would, and
handles error conditions in the same way.

'``llvm.exp.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.exp`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.exp.f32(float  %Val)
      declare double    @llvm.exp.f64(double %Val)
      declare x86_fp80  @llvm.exp.f80(x86_fp80  %Val)
      declare fp128     @llvm.exp.f128(fp128 %Val)
      declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.exp.*``' intrinsics perform the exp function.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the same values as the libm ``exp`` functions
would, and handles error conditions in the same way.

'``llvm.exp2.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.exp2`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.exp2.f32(float  %Val)
      declare double    @llvm.exp2.f64(double %Val)
      declare x86_fp80  @llvm.exp2.f80(x86_fp80  %Val)
      declare fp128     @llvm.exp2.f128(fp128 %Val)
      declare ppc_fp128 @llvm.exp2.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.exp2.*``' intrinsics perform the exp2 function.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the same values as the libm ``exp2`` functions
would, and handles error conditions in the same way.

'``llvm.log.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.log`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.log.f32(float  %Val)
      declare double    @llvm.log.f64(double %Val)
      declare x86_fp80  @llvm.log.f80(x86_fp80  %Val)
      declare fp128     @llvm.log.f128(fp128 %Val)
      declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.log.*``' intrinsics perform the log function.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the same values as the libm ``log`` functions
would, and handles error conditions in the same way.

'``llvm.log10.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.log10`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.log10.f32(float  %Val)
      declare double    @llvm.log10.f64(double %Val)
      declare x86_fp80  @llvm.log10.f80(x86_fp80  %Val)
      declare fp128     @llvm.log10.f128(fp128 %Val)
      declare ppc_fp128 @llvm.log10.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.log10.*``' intrinsics perform the log10 function.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the same values as the libm ``log10`` functions
would, and handles error conditions in the same way.

'``llvm.log2.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.log2`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.log2.f32(float  %Val)
      declare double    @llvm.log2.f64(double %Val)
      declare x86_fp80  @llvm.log2.f80(x86_fp80  %Val)
      declare fp128     @llvm.log2.f128(fp128 %Val)
      declare ppc_fp128 @llvm.log2.ppcf128(ppc_fp128  %Val)

Overview:
"""""""""

The '``llvm.log2.*``' intrinsics perform the log2 function.

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

The argument and return value are floating point numbers of the same
type.

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

This function returns the same values as the libm ``log2`` functions
would, and handles error conditions in the same way.

'``llvm.fma.*``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^

Syntax:
"""""""

This is an overloaded intrinsic. You can use ``llvm.fma`` on any
floating point or vector of floating point type. Not all targets support
all types however.

::

      declare float     @llvm.fma.f32(float  %a, float  %b, float  %c)
      declare double    @llvm.fma.f64(double %a, double %b, double %c)
      declare x86_fp80  @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
      declare fp128     @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
      declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)

Overview:
"""""""""