<li><a href="#modulestructure">Module Structure</a></li>
<li><a href="#linkage">Linkage Types</a></li>
<li><a href="#callingconv">Calling Conventions</a></li>
+ <li><a href="#namedtypes">Named Types</a></li>
<li><a href="#globalvars">Global Variables</a></li>
<li><a href="#functionstructure">Functions</a></li>
<li><a href="#aliasstructure">Aliases</a></li>
<li><a href="#t_opaque">Opaque Type</a></li>
</ol>
</li>
+ <li><a href="#t_uprefs">Type Up-references</a></li>
</ol>
</li>
<li><a href="#constants">Constants</a>
<ol>
<li><a href="#simpleconstants">Simple Constants</a></li>
- <li><a href="#aggregateconstants">Aggregate Constants</a></li>
+ <li><a href="#complexconstants">Complex Constants</a></li>
<li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
<li><a href="#undefvalues">Undefined Values</a></li>
<li><a href="#constantexprs">Constant Expressions</a></li>
+ <li><a href="#metadata">Embedded Metadata</a></li>
</ol>
</li>
<li><a href="#othervalues">Other Values</a>
<li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
</ol>
</li>
+ <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
+ <ol>
+ <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
+ <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
+ <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
+ <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
+ <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
+ <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
+ </ol>
+ </li>
<li><a href="#int_debugger">Debugger intrinsics</a></li>
<li><a href="#int_eh">Exception Handling intrinsics</a></li>
<li><a href="#int_trampoline">Trampoline Intrinsic</a>
<li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
</ol>
</li>
- <li><a href="#int_stackprotect">Stack Protector Intrinsic</a>
- <ol>
- <li><a href="#int_ssp">'<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
- </ol>
- </li>
<li><a href="#int_atomics">Atomic intrinsics</a>
<ol>
<li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
<li><a href="#int_general">General intrinsics</a>
<ol>
<li><a href="#int_var_annotation">
- <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
+ '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
<li><a href="#int_annotation">
- <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
+ '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
<li><a href="#int_trap">
- <tt>llvm.trap</tt>' Intrinsic</a></li>
+ '<tt>llvm.trap</tt>' Intrinsic</a></li>
+ <li><a href="#int_stackprotector">
+ '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
</ol>
</li>
</ol>
<i>; Definition of main function</i>
define i32 @main() { <i>; i32()* </i>
- <i>; Convert [13x i8 ]* to i8 *...</i>
+ <i>; Convert [13 x i8]* to i8 *...</i>
%cast210 = <a
- href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
+ href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
<i>; Call puts function to write out the string to stdout...</i>
<a
<dl>
- <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
+ <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
- <dd>Global values with internal linkage are only directly accessible by
+ <dd>Global values with private linkage are only directly accessible by
objects in the current module. In particular, linking code into a module with
- an internal global value may cause the internal to be renamed as necessary to
- avoid collisions. Because the symbol is internal to the module, all
- references can be updated. This corresponds to the notion of the
+ an private global value may cause the private to be renamed as necessary to
+ avoid collisions. Because the symbol is private to the module, all
+ references can be updated. This doesn't show up in any symbol table in the
+ object file.
+ </dd>
+
+ <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
+
+ <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
+ the case of ELF) in the object file. This corresponds to the notion of the
'<tt>static</tt>' keyword in C.
</dd>
+ <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
+ </dt>
+
+ <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
+ into the object file corresponding to the LLVM module. They exist to
+ allow inlining and other optimizations to take place given knowledge of the
+ definition of the global, which is known to be somewhere outside the module.
+ Globals with <tt>available_externally</tt> linkage are allowed to be discarded
+ at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
+ type is only allowed on definitions, not declarations.</dd>
+
<dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
<dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
</dd>
<dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
+
<dd>The semantics of this linkage follow the ELF object file model: the
symbol is weak until linked, if not linked, the symbol becomes null instead
of being an undefined reference.
</dd>
+ <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
+ <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
+ <dd>Some languages allow differing globals to be merged, such as two
+ functions with different semantics. Other languages, such as <tt>C++</tt>,
+ ensure that only equivalent globals are ever merged (the "one definition
+ rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
+ and <tt>weak_odr</tt> linkage types to indicate that the global will only
+ be merged with equivalent globals. These linkage types are otherwise the
+ same as their non-<tt>odr</tt> versions.
+ </dd>
+
<dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
<dd>If none of the above identifiers are used, the global is externally
<dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
or variable via a global pointer to a pointer that is set up by the DLL
exporting the symbol. On Microsoft Windows targets, the pointer name is
- formed by combining <code>_imp__</code> and the function or variable name.
+ formed by combining <code>__imp_</code> and the function or variable name.
</dd>
<dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
<dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
pointer to a pointer in a DLL, so that it can be referenced with the
<tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
- name is formed by combining <code>_imp__</code> and the function or variable
+ name is formed by combining <code>__imp_</code> and the function or variable
name.
</dd>
</dl>
-<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
+<p>For example, since the "<tt>.LC0</tt>"
variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
variable and was linked with this one, one of the two would be renamed,
preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
external (i.e., lacking any linkage declarations), they are accessible
outside of the current module.</p>
<p>It is illegal for a function <i>declaration</i>
-to have any linkage type other than "externally visible", <tt>dllimport</tt>,
+to have any linkage type other than "externally visible", <tt>dllimport</tt>
or <tt>extern_weak</tt>.</p>
-<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
-linkages.</p>
+<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
+or <tt>weak_odr</tt> linkages.</p>
</div>
<!-- ======================================================================= -->
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="namedtypes">Named Types</a>
+</div>
+
+<div class="doc_text">
+
+<p>LLVM IR allows you to specify name aliases for certain types. This can make
+it easier to read the IR and make the IR more condensed (particularly when
+recursive types are involved). An example of a name specification is:
+</p>
+
+<div class="doc_code">
+<pre>
+%mytype = type { %mytype*, i32 }
+</pre>
+</div>
+
+<p>You may give a name to any <a href="#typesystem">type</a> except "<a
+href="t_void">void</a>". Type name aliases may be used anywhere a type is
+expected with the syntax "%mytype".</p>
+
+<p>Note that type names are aliases for the structural type that they indicate,
+and that you can therefore specify multiple names for the same type. This often
+leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
+structural typing, the name is not part of the type. When printing out LLVM IR,
+the printer will pick <em>one name</em> to render all types of a particular
+shape. This means that if you have code where two different source types end up
+having the same LLVM type, that the dumper will sometimes print the "wrong" or
+unexpected type. This is an important design point and isn't going to
+change.</p>
+
+</div>
+
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="globalvars">Global Variables</a>
<div class="doc_code">
<pre>
-@G = constant float 1.0 addrspace(5), section "foo", align 4
+@G = addrspace(5) constant float 1.0, section "foo", align 4
</pre>
</div>
<div class="doc_code">
<pre>
-declare i32 @printf(i8* noalias , ...)
+declare i32 @printf(i8* noalias nocapture, ...)
declare i32 @atoi(i8 zeroext)
declare signext i8 @returns_signed_char()
</pre>
belong to the caller not the callee (for example,
<tt><a href="#readonly">readonly</a></tt> functions should not write to
<tt>byval</tt> parameters). This is not a valid attribute for return
- values. </dd>
+ values. The byval attribute also supports specifying an alignment with the
+ align attribute. This has a target-specific effect on the code generator
+ that usually indicates a desired alignment for the synthesized stack
+ slot.</dd>
<dt><tt>sret</tt></dt>
<dd>This indicates that the pointer parameter specifies the address of a
return values. </dd>
<dt><tt>noalias</tt></dt>
- <dd>This indicates that the parameter does not alias any global or any other
- parameter. The caller is responsible for ensuring that this is the case,
- usually by placing the value in a stack allocation. This is not a valid
- attribute for return values.</dd>
+ <dd>This indicates that the pointer does not alias any global or any other
+ parameter. The caller is responsible for ensuring that this is the
+ case. On a function return value, <tt>noalias</tt> additionally indicates
+ that the pointer does not alias any other pointers visible to the
+ caller. For further details, please see the discussion of the NoAlias
+ response in
+ <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
+ analysis</a>.</dd>
+
+ <dt><tt>nocapture</tt></dt>
+ <dd>This indicates that the callee does not make any copies of the pointer
+ that outlive the callee itself. This is not a valid attribute for return
+ values.</dd>
<dt><tt>nest</tt></dt>
<dd>This indicates that the pointer parameter can be excised using the
behavior is undefined.</dd>
<dt><tt>readnone</tt></dt>
-<dd>This attribute indicates that the function computes its result (or the
-exception it throws) based strictly on its arguments, without dereferencing any
+<dd>This attribute indicates that the function computes its result (or decides to
+unwind an exception) based strictly on its arguments, without dereferencing any
pointer arguments or otherwise accessing any mutable state (e.g. memory, control
registers, etc) visible to caller functions. It does not write through any
pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
-never changes any state visible to callers.</dd>
+never changes any state visible to callers. This means that it cannot unwind
+exceptions by calling the <tt>C++</tt> exception throwing methods, but could
+use the <tt>unwind</tt> instruction.</dd>
<dt><tt><a name="readonly">readonly</a></tt></dt>
<dd>This attribute indicates that the function does not write through any
or otherwise modify any state (e.g. memory, control registers, etc) visible to
caller functions. It may dereference pointer arguments and read state that may
be set in the caller. A readonly function always returns the same value (or
-throws the same exception) when called with the same set of arguments and global
-state.</dd>
+unwinds an exception identically) when called with the same set of arguments
+and global state. It cannot unwind an exception by calling the <tt>C++</tt>
+exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
<dt><tt><a name="ssp">ssp</a></tt></dt>
<dd>This attribute indicates that the function should emit a stack smashing
protector. It is in the form of a "canary"—a random value placed on the
stack before the local variables that's checked upon return from the function to
see if it has been overwritten. A heuristic is used to determine if a function
-needs stack protectors or not.</dd>
+needs stack protectors or not.
+
+<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
+that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
+have an <tt>ssp</tt> attribute.</p></dd>
-<dt><tt>ssp-req</tt></dt>
+<dt><tt>sspreq</tt></dt>
<dd>This attribute indicates that the function should <em>always</em> emit a
stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
-function attribute.</dd>
+function attribute.
+
+<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
+function that doesn't have an <tt>sspreq</tt> attribute or which has
+an <tt>ssp</tt> attribute, then the resulting function will have
+an <tt>sspreq</tt> attribute.</p></dd>
</dl>
</div>
</tr>
</tbody>
</table>
+
+<p>Note that the code generator does not yet support large integer types
+to be used as function return types. The specific limit on how large a
+return type the code generator can currently handle is target-dependent;
+currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
+targets.</p>
+
</div>
<!-- _______________________________________________________________________ -->
length. This allows implementation of 'pascal style arrays' with the LLVM
type "{ i32, [0 x float]}", for example.</p>
+<p>Note that the code generator does not yet support large aggregate types
+to be used as function return types. The specific limit on how large an
+aggregate return type the code generator can currently handle is
+target-dependent, and also dependent on the aggregate element types.</p>
+
</div>
<!-- _______________________________________________________________________ -->
</td>
</tr><tr class="layout">
<td class="left"><tt>{i32, i32} (i32)</tt></td>
- <td class="left">A function taking an <tt>i32></tt>, returning two
- <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
+ <td class="left">A function taking an <tt>i32</tt>, returning two
+ <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
</td>
</tr>
</table>
an <tt>i32</tt>.</td>
</tr>
</table>
+
+<p>Note that the code generator does not yet support large aggregate types
+to be used as function return types. The specific limit on how large an
+aggregate return type the code generator can currently handle is
+target-dependent, and also dependent on the aggregate element types.</p>
+
</div>
<!-- _______________________________________________________________________ -->
an optional address space attribute defining the target-specific numbered
address space where the pointed-to object resides. The default address space is
zero.</p>
+
+<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does
+it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
+
<h5>Syntax:</h5>
<pre> <type> *<br></pre>
<h5>Examples:</h5>
<table class="layout">
<tr class="layout">
- <td class="left"><tt>[4x i32]*</tt></td>
+ <td class="left"><tt>[4 x i32]*</tt></td>
<td class="left">A <a href="#t_pointer">pointer</a> to <a
href="#t_array">array</a> of four <tt>i32</tt> values.</td>
</tr>
<td class="left">Vector of 2 64-bit integer values.</td>
</tr>
</table>
+
+<p>Note that the code generator does not yet support large vector types
+to be used as function return types. The specific limit on how large a
+vector return type codegen can currently handle is target-dependent;
+currently it's often a few times longer than a hardware vector register.</p>
+
</div>
<!-- _______________________________________________________________________ -->
</table>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="t_uprefs">Type Up-references</a>
+</div>
+
+<div class="doc_text">
+<h5>Overview:</h5>
+<p>
+An "up reference" allows you to refer to a lexically enclosing type without
+requiring it to have a name. For instance, a structure declaration may contain a
+pointer to any of the types it is lexically a member of. Example of up
+references (with their equivalent as named type declarations) include:</p>
+
+<pre>
+ { \2 * } %x = type { %x* }
+ { \2 }* %y = type { %y }*
+ \1* %z = type %z*
+</pre>
+
+<p>
+An up reference is needed by the asmprinter for printing out cyclic types when
+there is no declared name for a type in the cycle. Because the asmprinter does
+not want to print out an infinite type string, it needs a syntax to handle
+recursive types that have no names (all names are optional in llvm IR).
+</p>
+
+<h5>Syntax:</h5>
+<pre>
+ \<level>
+</pre>
+
+<p>
+The level is the count of the lexical type that is being referred to.
+</p>
+
+<h5>Examples:</h5>
+
+<table class="layout">
+ <tr class="layout">
+ <td class="left"><tt>\1*</tt></td>
+ <td class="left">Self-referential pointer.</td>
+ </tr>
+ <tr class="layout">
+ <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
+ <td class="left">Recursive structure where the upref refers to the out-most
+ structure.</td>
+ </tr>
+</table>
+</div>
+
<!-- *********************************************************************** -->
<div class="doc_section"> <a name="constants">Constants</a> </div>
</dl>
-<p>The one non-intuitive notation for constants is the optional hexadecimal form
+<p>The one non-intuitive notation for constants is the hexadecimal form
of floating point constants. For example, the form '<tt>double
0x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
4.5e+15</tt>'. The only time hexadecimal floating point constants are required
(and the only time that they are generated by the disassembler) is when a
floating point constant must be emitted but it cannot be represented as a
-decimal floating point number. For example, NaN's, infinities, and other
+decimal floating point number in a reasonable number of digits. For example,
+NaN's, infinities, and other
special values are represented in their IEEE hexadecimal format so that
assembly and disassembly do not cause any bits to change in the constants.</p>
-
+<p>When using the hexadecimal form, constants of types float and double are
+represented using the 16-digit form shown above (which matches the IEEE754
+representation for double); float values must, however, be exactly representable
+as IEE754 single precision.
+Hexadecimal format is always used for long
+double, and there are three forms of long double. The 80-bit
+format used by x86 is represented as <tt>0xK</tt>
+followed by 20 hexadecimal digits.
+The 128-bit format used by PowerPC (two adjacent doubles) is represented
+by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
+format is represented
+by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
+target uses this format. Long doubles will only work if they match
+the long double format on your target. All hexadecimal formats are big-endian
+(sign bit at the left).</p>
</div>
<!-- ======================================================================= -->
-<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
+<div class="doc_subsection">
+<a name="aggregateconstants"> <!-- old anchor -->
+<a name="complexconstants">Complex Constants</a></a>
</div>
<div class="doc_text">
-<p>Aggregate constants arise from aggregation of simple constants
-and smaller aggregate constants.</p>
+<p>Complex constants are a (potentially recursive) combination of simple
+constants and smaller complex constants.</p>
<dl>
<dt><b>Structure constants</b></dt>
large arrays) and is always exactly equivalent to using explicit zero
initializers.
</dd>
+
+ <dt><b>Metadata node</b></dt>
+
+ <dd>A metadata node is a structure-like constant with the type of an empty
+ struct. For example: "<tt>{ } !{ i32 0, { } !"test" }</tt>". Unlike other
+ constants that are meant to be interpreted as part of the instruction stream,
+ metadata is a place to attach additional information such as debug info.
+ </dd>
</dl>
</div>
<i>really</i> dangerous!</dd>
<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
- <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
- identical (same number of bits). The conversion is done as if the CST value
- was stored to memory and read back as TYPE. In other words, no bits change
- with this operator, just the type. This can be used for conversion of
- vector types to any other type, as long as they have the same bit width. For
- pointers it is only valid to cast to another pointer type. It is not valid
- to bitcast to or from an aggregate type.
- </dd>
+ <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
+ are the same as those for the <a href="#i_bitcast">bitcast
+ instruction</a>.</dd>
<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
</dl>
</div>
+<!-- ======================================================================= -->
+<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
+</div>
+
+<div class="doc_text">
+
+<p>Embedded metadata provides a way to attach arbitrary data to the
+instruction stream without affecting the behaviour of the program. There are
+two metadata primitives, strings and nodes. All metadata has the type of an
+empty struct and is identified in syntax by a preceding exclamation point
+('<tt>!</tt>').
+</p>
+
+<p>A metadata string is a string surrounded by double quotes. It can contain
+any character by escaping non-printable characters with "\xx" where "xx" is
+the two digit hex code. For example: "<tt>!"test\00"</tt>".
+</p>
+
+<p>Metadata nodes are represented with notation similar to structure constants
+(a comma separated list of elements, surrounded by braces and preceeded by an
+exclamation point). For example: "<tt>!{ { } !"test\00", i32 10}</tt>".
+</p>
+
+<p>Optimizations may rely on metadata to provide additional information about
+the program that isn't available in the instructions, or that isn't easily
+computable. Similarly, the code generator may expect a certain metadata format
+to be used to express debugging information.</p>
+</div>
+
<!-- *********************************************************************** -->
<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
<!-- *********************************************************************** -->
<pre>
ret i32 5 <i>; Return an integer value of 5</i>
ret void <i>; Return from a void function</i>
- ret { i32, i8 } { i32 4, i8 2 } <i>; Return an aggregate of values 4 and 2</i>
+ ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
</pre>
+
+<p>Note that the code generator does not yet fully support large
+ return values. The specific sizes that are currently supported are
+ dependent on the target. For integers, on 32-bit targets the limit
+ is often 64 bits, and on 64-bit targets the limit is often 128 bits.
+ For aggregate types, the current limits are dependent on the element
+ types; for example targets are often limited to 2 total integer
+ elements and 2 total floating-point elements.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
<h5>Example:</h5>
-<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq
, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
+<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
</div>
<!-- _______________________________________________________________________ -->
<pre>
<i>; Emulate a conditional br instruction</i>
%Val = <a href="#i_zext">zext</a> i1 %value to i32
- switch i32 %Val, label %truedest [i32 0, label %falsedest ]
+ switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
<i>; Emulate an unconditional br instruction</i>
switch i32 0, label %dest [ ]
<i>; Implement a jump table:</i>
- switch i32 %val, label %otherwise [ i32 0, label %onzero
- i32 1, label %onone
- i32 2, label %ontwo ]
+ switch i32 %val, label %otherwise [ i32 0, label %onzero
+ i32 1, label %onone
+ i32 2, label %ontwo ]
</pre>
</div>
<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
-equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.</p>
+equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
+If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
+corresponding shift amount in <tt>op2</tt>.</p>
<h5>Example:</h5><pre>
<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
<result> = shl i32 1, 32 <i>; undefined</i>
+ <result> = shl <2 x i32> < i32 1, i32 1>, < i32 1, i32 2> <i>; yields: result=<2 x i32> < i32 2, i32 4></i>
</pre>
</div>
<!-- _______________________________________________________________________ -->
<p>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 <tt>op2</tt> is (statically or dynamically) equal to or larger than
-the number of bits in <tt>op1</tt>, the result is undefined.</p>
+the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
+vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
+amount in <tt>op2</tt>.</p>
<h5>Example:</h5>
<pre>
<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
<result> = lshr i32 1, 32 <i>; undefined</i>
+ <result> = lshr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 2> <i>; yields: result=<2 x i32> < i32 0x7FFFFFFF, i32 1></i>
</pre>
</div>
<p>This instruction always performs an arithmetic shift right operation,
The most significant bits of the result will be filled with the sign bit
of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
-larger than the number of bits in <tt>op1</tt>, the result is undefined.
-</p>
+larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
+arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
+corresponding shift amount in <tt>op2</tt>.</p>
<h5>Example:</h5>
<pre>
<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
<result> = ashr i32 1, 32 <i>; undefined</i>
+ <result> = ashr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 3> <i>; yields: result=<2 x i32> < i32 -1, i32 0></i>
</pre>
</div>
<h5>Semantics:</h5>
<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
-a pointer is returned. The result of a zero byte allocattion is undefined. The
+a pointer is returned. The result of a zero byte allocation is undefined. The
result is null if there is insufficient memory available.</p>
<h5>Example:</h5>
<pre>
- %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
+ %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
%size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
%array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
%array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
%array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
</pre>
+
+<p>Note that the code generator does not yet respect the
+ alignment value.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<h5>Syntax:</h5>
<pre>
- free <type> <value> <i>; yields {void}</i>
+ free <type> <value> <i>; yields {void}</i>
</pre>
<h5>Overview:</h5>
<h5>Example:</h5>
<pre>
- %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
+ %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
free [4 x i8]* %array
</pre>
</div>
<h5>Semantics:</h5>
-<p>Memory is allocated; a pointer is returned. The operation is undefiend if
+<p>Memory is allocated; a pointer is returned. The operation is undefined if
there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
memory is automatically released when the function returns. The '<tt>alloca</tt>'
instruction is commonly used to represent automatic variables that must
<h5>Example:</h5>
<pre>
- %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
- %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
- %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
- %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
+ %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
+ %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
+ %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
+ %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
</pre>
</div>
safe.
</p>
<h5>Semantics:</h5>
-<p>The location of memory pointed to is loaded.</p>
+<p>The location of memory pointed to is loaded. If the value being loaded
+is of scalar type then the number of bytes read does not exceed the minimum
+number of bytes needed to hold all bits of the type. For example, loading an
+<tt>i24</tt> reads at most three bytes. When loading a value of a type like
+<tt>i20</tt> with a size that is not an integral number of bytes, the result
+is undefined if the value was not originally written using a store of the
+same type.</p>
<h5>Examples:</h5>
<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
<a
</p>
<h5>Semantics:</h5>
<p>The contents of memory are updated to contain '<tt><value></tt>'
-at the location specified by the '<tt><pointer></tt>' operand.</p>
+at the location specified by the '<tt><pointer></tt>' operand.
+If '<tt><value></tt>' is of scalar type then the number of bytes
+written does not exceed the minimum number of bytes needed to hold all
+bits of the type. For example, storing an <tt>i24</tt> writes at most
+three bytes. When writing a value of a type like <tt>i20</tt> with a
+size that is not an integral number of bytes, it is unspecified what
+happens to the extra bits that do not belong to the type, but they will
+typically be overwritten.</p>
<h5>Example:</h5>
<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
store i32 3, i32* %ptr <i>; yields {void}</i>
<p>The type of each index argument depends on the type it is indexing into.
When indexing into a (packed) structure, only <tt>i32</tt> integer
<b>constants</b> are allowed. When indexing into an array, pointer or vector,
-only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
-will be sign extended to 64-bits if required.</p>
+integers of any width are allowed (also non-constants).</p>
<p>For example, let's consider a C code fragment and how it gets
compiled to LLVM:</p>
<div class="doc_code">
<pre>
-%RT = type { i8 , [10 x [20 x i32]], i8 }
-%ST = type { i32, double, %RT }
+%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
+%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
define i32* %foo(%ST* %s) {
entry:
}
</pre>
-<p>Note that it is undefined to access an array out of bounds: array and
-pointer indexes must always be within the defined bounds of the array type.
-The one exception for this rule is zero length arrays. These arrays are
-defined to be accessible as variable length arrays, which requires access
-beyond the zero'th element.</p>
+<p>Note that it is undefined to access an array out of bounds: array
+and pointer indexes must always be within the defined bounds of the
+array type when accessed with an instruction that dereferences the
+pointer (e.g. a load or store instruction). The one exception for
+this rule is zero length arrays. These arrays are defined to be
+accessible as variable length arrays, which requires access beyond the
+zero'th element.</p>
<p>The getelementptr instruction is often confusing. For some more insight
into how it works, see <a href="GetElementPtr.html">the getelementptr
%vptr = getelementptr {i32, <2 x i8>}* %svptr, i64 0, i32 1, i32 1
<i>; yields i8*:eptr</i>
%eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
+ <i>; yields i32*:iptr</i>
+ %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
</pre>
</div>
<result> = icmp ule i16 -4, 5 <i>; yields: result=false</i>
<result> = icmp sge i16 4, 5 <i>; yields: result=false</i>
</pre>
+
+<p>Note that the code generator does not yet support vector types with
+ the <tt>icmp</tt> instruction.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<result> = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
<result> = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
</pre>
+
+<p>Note that the code generator does not yet support vector types with
+ the <tt>fcmp</tt> instruction.</p>
+
</div>
<!-- _______________________________________________________________________ -->
<pre>
%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
</pre>
+
+<p>Note that the code generator does not yet support conditions
+ with vector type.</p>
+
</div>
<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
+<p>Note that the code generator does not yet fully support va_arg
+ on many targets. Also, it does not currently support va_arg with
+ aggregate types on any target.</p>
+
</div>
<!-- *********************************************************************** -->
<div class="doc_text">
<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
+width. Not all targets support all bit widths however.</p>
<pre>
+ declare void @llvm.memcpy.i8(i8 * <dest>, i8 * <src>,
+ i8 <len>, i32 <align>)
+ declare void @llvm.memcpy.i16(i8 * <dest>, i8 * <src>,
+ i16 <len>, i32 <align>)
declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
i32 <len>, i32 <align>)
declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>,
<div class="doc_text">
<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
+width. Not all targets support all bit widths however.</p>
<pre>
+ declare void @llvm.memmove.i8(i8 * <dest>, i8 * <src>,
+ i8 <len>, i32 <align>)
+ declare void @llvm.memmove.i16(i8 * <dest>, i8 * <src>,
+ i16 <len>, i32 <align>)
declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
i32 <len>, i32 <align>)
declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>,
<div class="doc_text">
<h5>Syntax:</h5>
+<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
+width. Not all targets support all bit widths however.</p>
<pre>
+ declare void @llvm.memset.i8(i8 * <dest>, i8 <val>,
+ i8 <len>, i32 <align>)
+ declare void @llvm.memset.i16(i8 * <dest>, i8 <val>,
+ i16 <len>, i32 <align>)
declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
i32 <len>, i32 <align>)
declare void @llvm.memset.i64(i8 * <dest>, i8 <val>,
<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
width. Not all targets support all bit widths however.</p>
<pre>
- declare i8 @llvm.ctpop.i8 (i8 <src>)
+ declare i8 @llvm.ctpop.i8(i8 <src>)
declare i16 @llvm.ctpop.i16(i16 <src>)
declare i32 @llvm.ctpop.i32(i32 <src>)
declare i64 @llvm.ctpop.i64(i64 <src>)
with the replaced bits.</p>
<h5>Arguments:</h5>
-<p>The first argument, <tt>%val</tt> and the result may be integer types of
-any bit width but they must have the same bit width. <tt>%val</tt> is the value
+<p>The first argument, <tt>%val</tt>, and the result may be integer types of
+any bit width, but they must have the same bit width. <tt>%val</tt> is the value
whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
type since they specify only a bit index.</p>
of operation: forwards and reverse. If <tt>%lo</tt> is greater than
<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
operates in forward mode.</p>
+
<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
truncating it down to the size of the replacement area or zero extending it
up to that size.</p>
+
<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
to the <tt>%hi</tt>th bit.</p>
+
<p>In reverse mode, a similar computation is made except that the bits are
reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
+
<h5>Examples:</h5>
+
<pre>
llvm.part.set(0xFFFF, 0, 4, 7) -> 0xFF0F
llvm.part.set(0xFFFF, 0, 7, 4) -> 0xFF0F
llvm.part.set(0xFFFF, F, 8, 3) -> 0xFFE7
llvm.part.set(0xFFFF, 0, 3, 8) -> 0xFE07
</pre>
+
+</div>
+
+<!-- ======================================================================= -->
+<div class="doc_subsection">
+ <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
+</div>
+
+<div class="doc_text">
+<p>
+LLVM provides intrinsics for some arithmetic with overflow operations.
+</p>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
+on any integer bit width.</p>
+
+<pre>
+ declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
+ declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
+ declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
+a signed addition of the two arguments, and indicate whether an overflow
+occurred during the signed summation.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments (%a and %b) and the first element of the result structure may
+be of integer types of any bit width, but they must have the same bit width. The
+second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
+and <tt>%b</tt> are the two values that will undergo signed addition.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
+a signed addition of the two variables. They return a structure — the
+first element of which is the signed summation, and the second element of which
+is a bit specifying if the signed summation resulted in an overflow.</p>
+
+<h5>Examples:</h5>
+<pre>
+ %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
+ %sum = extractvalue {i32, i1} %res, 0
+ %obit = extractvalue {i32, i1} %res, 1
+ br i1 %obit, label %overflow, label %normal
+</pre>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
+on any integer bit width.</p>
+
+<pre>
+ declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
+ declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
+ declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
+an unsigned addition of the two arguments, and indicate whether a carry occurred
+during the unsigned summation.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments (%a and %b) and the first element of the result structure may
+be of integer types of any bit width, but they must have the same bit width. The
+second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
+and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
+an unsigned addition of the two arguments. They return a structure — the
+first element of which is the sum, and the second element of which is a bit
+specifying if the unsigned summation resulted in a carry.</p>
+
+<h5>Examples:</h5>
+<pre>
+ %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
+ %sum = extractvalue {i32, i1} %res, 0
+ %obit = extractvalue {i32, i1} %res, 1
+ br i1 %obit, label %carry, label %normal
+</pre>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
+on any integer bit width.</p>
+
+<pre>
+ declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
+ declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
+ declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
+a signed subtraction of the two arguments, and indicate whether an overflow
+occurred during the signed subtraction.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments (%a and %b) and the first element of the result structure may
+be of integer types of any bit width, but they must have the same bit width. The
+second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
+and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
+a signed subtraction of the two arguments. They return a structure — the
+first element of which is the subtraction, and the second element of which is a bit
+specifying if the signed subtraction resulted in an overflow.</p>
+
+<h5>Examples:</h5>
+<pre>
+ %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
+ %sum = extractvalue {i32, i1} %res, 0
+ %obit = extractvalue {i32, i1} %res, 1
+ br i1 %obit, label %overflow, label %normal
+</pre>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
+on any integer bit width.</p>
+
+<pre>
+ declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
+ declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
+ declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
+an unsigned subtraction of the two arguments, and indicate whether an overflow
+occurred during the unsigned subtraction.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments (%a and %b) and the first element of the result structure may
+be of integer types of any bit width, but they must have the same bit width. The
+second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
+and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
+an unsigned subtraction of the two arguments. They return a structure — the
+first element of which is the subtraction, and the second element of which is a bit
+specifying if the unsigned subtraction resulted in an overflow.</p>
+
+<h5>Examples:</h5>
+<pre>
+ %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
+ %sum = extractvalue {i32, i1} %res, 0
+ %obit = extractvalue {i32, i1} %res, 1
+ br i1 %obit, label %overflow, label %normal
+</pre>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
+on any integer bit width.</p>
+
+<pre>
+ declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
+ declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
+ declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
+</pre>
+
+<h5>Overview:</h5>
+
+<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
+a signed multiplication of the two arguments, and indicate whether an overflow
+occurred during the signed multiplication.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments (%a and %b) and the first element of the result structure may
+be of integer types of any bit width, but they must have the same bit width. The
+second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
+and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
+a signed multiplication of the two arguments. They return a structure —
+the first element of which is the multiplication, and the second element of
+which is a bit specifying if the signed multiplication resulted in an
+overflow.</p>
+
+<h5>Examples:</h5>
+<pre>
+ %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
+ %sum = extractvalue {i32, i1} %res, 0
+ %obit = extractvalue {i32, i1} %res, 1
+ br i1 %obit, label %overflow, label %normal
+</pre>
+
+</div>
+
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
+</div>
+
+<div class="doc_text">
+
+<h5>Syntax:</h5>
+
+<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
+on any integer bit width.</p>
+
+<pre>
+ declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
+ declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
+ declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
+</pre>
+
+<h5>Overview:</h5>
+
+<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
+actively being fixed, but it should not currently be used!</i></p>
+
+<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
+a unsigned multiplication of the two arguments, and indicate whether an overflow
+occurred during the unsigned multiplication.</p>
+
+<h5>Arguments:</h5>
+
+<p>The arguments (%a and %b) and the first element of the result structure may
+be of integer types of any bit width, but they must have the same bit width. The
+second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
+and <tt>%b</tt> are the two values that will undergo unsigned
+multiplication.</p>
+
+<h5>Semantics:</h5>
+
+<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
+an unsigned multiplication of the two arguments. They return a structure —
+the first element of which is the multiplication, and the second element of
+which is a bit specifying if the unsigned multiplication resulted in an
+overflow.</p>
+
+<h5>Examples:</h5>
+<pre>
+ %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
+ %sum = extractvalue {i32, i1} %res, 0
+ %obit = extractvalue {i32, i1} %res, 1
+ br i1 %obit, label %overflow, label %normal
+</pre>
+
</div>
<!-- ======================================================================= -->
</p>
</div>
-<!-- ======================================================================= -->
-<div class="doc_subsection">
- <a name="int_stackprotect">Stack Protector Intrinsic</a>
-</div>
-
-<div class="doc_text">
-<p>
- This intrinsic is used when stack protectors are required. LLVM generates a
- call to load the randomized stack protector guard's value. The intrinsic is
- used so that LLVM can ensure that the stack guard is placed onto the stack in
- the appropriate place—before local variables are allocated on the stack.
-</p>
-</div>
-
-<!-- _______________________________________________________________________ -->
-<div class="doc_subsubsection">
- <a name="int_ssp">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
-</div>
-<div class="doc_text">
-<h5>Syntax:</h5>
-<pre>
-declare void @llvm.stackprotector( i8* <guard>, i8** <slot> )
-
-</pre>
-<h5>Overview:</h5>
-<p>
- The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
- it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
- it's before local variables are allocated on the stack.
-</p>
-<h5>Arguments:</h5>
-<p>
- The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
- first argument is the value loaded from the stack guard
- <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
- has enough space to hold the value of the guard.
-</p>
-<h5>Semantics:</h5>
-<p>
- This intrinsic causes the prologue/epilogue inserter to force the position of
- the <tt>AllocaInst</tt> stack slot to be before local variables on the
- stack. This is to ensure that if a local variable on the stack is overwritten,
- it will destroy the value of the guard. When the function exits, the guard on
- the stack is checked against the original guard. If they're different, then
- the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
-</p>
-</div>
-
<!-- ======================================================================= -->
<div class="doc_subsection">
<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
</p>
</div>
+<!-- _______________________________________________________________________ -->
+<div class="doc_subsubsection">
+ <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
+</div>
+<div class="doc_text">
+<h5>Syntax:</h5>
+<pre>
+declare void @llvm.stackprotector( i8* <guard>, i8** <slot> )
+
+</pre>
+<h5>Overview:</h5>
+<p>
+ The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
+ it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
+ it is placed on the stack before local variables.
+</p>
+<h5>Arguments:</h5>
+<p>
+ The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
+ first argument is the value loaded from the stack guard
+ <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
+ has enough space to hold the value of the guard.
+</p>
+<h5>Semantics:</h5>
+<p>
+ This intrinsic causes the prologue/epilogue inserter to force the position of
+ the <tt>AllocaInst</tt> stack slot to be before local variables on the
+ stack. This is to ensure that if a local variable on the stack is overwritten,
+ it will destroy the value of the guard. When the function exits, the guard on
+ the stack is checked against the original guard. If they're different, then
+ the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
+</p>
+</div>
+
<!-- *********************************************************************** -->
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<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
projects / oota-llvm.git / blobdiff