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<title>GNU Compiler Collection (GCC) Internals: Addressing Modes</title>
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<a name="Addressing-Modes"></a>
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<div class="header">
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<p>
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Next: <a href="Anchored-Addresses.html#Anchored-Addresses" accesskey="n" rel="next">Anchored Addresses</a>, Previous: <a href="Library-Calls.html#Library-Calls" accesskey="p" rel="prev">Library Calls</a>, Up: <a href="Target-Macros.html#Target-Macros" accesskey="u" rel="up">Target Macros</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Addressing-Modes-1"></a>
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<h3 class="section">17.13 Addressing Modes</h3>
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<a name="index-addressing-modes"></a>
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<p>This is about addressing modes.
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</p>
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<dl>
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<dt><a name="index-HAVE_005fPRE_005fINCREMENT"></a>Macro: <strong>HAVE_PRE_INCREMENT</strong></dt>
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<dt><a name="index-HAVE_005fPRE_005fDECREMENT"></a>Macro: <strong>HAVE_PRE_DECREMENT</strong></dt>
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<dt><a name="index-HAVE_005fPOST_005fINCREMENT"></a>Macro: <strong>HAVE_POST_INCREMENT</strong></dt>
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<dt><a name="index-HAVE_005fPOST_005fDECREMENT"></a>Macro: <strong>HAVE_POST_DECREMENT</strong></dt>
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<dd><p>A C expression that is nonzero if the machine supports pre-increment,
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pre-decrement, post-increment, or post-decrement addressing respectively.
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</p></dd></dl>
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<dl>
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<dt><a name="index-HAVE_005fPRE_005fMODIFY_005fDISP"></a>Macro: <strong>HAVE_PRE_MODIFY_DISP</strong></dt>
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<dt><a name="index-HAVE_005fPOST_005fMODIFY_005fDISP"></a>Macro: <strong>HAVE_POST_MODIFY_DISP</strong></dt>
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<dd><p>A C expression that is nonzero if the machine supports pre- or
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post-address side-effect generation involving constants other than
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the size of the memory operand.
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</p></dd></dl>
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<dl>
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<dt><a name="index-HAVE_005fPRE_005fMODIFY_005fREG"></a>Macro: <strong>HAVE_PRE_MODIFY_REG</strong></dt>
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<dt><a name="index-HAVE_005fPOST_005fMODIFY_005fREG"></a>Macro: <strong>HAVE_POST_MODIFY_REG</strong></dt>
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<dd><p>A C expression that is nonzero if the machine supports pre- or
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post-address side-effect generation involving a register displacement.
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</p></dd></dl>
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<dl>
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<dt><a name="index-CONSTANT_005fADDRESS_005fP"></a>Macro: <strong>CONSTANT_ADDRESS_P</strong> <em>(<var>x</var>)</em></dt>
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<dd><p>A C expression that is 1 if the RTX <var>x</var> is a constant which
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is a valid address. On most machines the default definition of
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<code>(CONSTANT_P (<var>x</var>) && GET_CODE (<var>x</var>) != CONST_DOUBLE)</code>
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is acceptable, but a few machines are more restrictive as to which
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constant addresses are supported.
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</p></dd></dl>
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<dl>
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<dt><a name="index-CONSTANT_005fP"></a>Macro: <strong>CONSTANT_P</strong> <em>(<var>x</var>)</em></dt>
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<dd><p><code>CONSTANT_P</code>, which is defined by target-independent code,
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accepts integer-values expressions whose values are not explicitly
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known, such as <code>symbol_ref</code>, <code>label_ref</code>, and <code>high</code>
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expressions and <code>const</code> arithmetic expressions, in addition to
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<code>const_int</code> and <code>const_double</code> expressions.
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</p></dd></dl>
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<dl>
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<dt><a name="index-MAX_005fREGS_005fPER_005fADDRESS"></a>Macro: <strong>MAX_REGS_PER_ADDRESS</strong></dt>
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<dd><p>A number, the maximum number of registers that can appear in a valid
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memory address. Note that it is up to you to specify a value equal to
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the maximum number that <code>TARGET_LEGITIMATE_ADDRESS_P</code> would ever
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accept.
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</p></dd></dl>
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<dl>
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<dt><a name="index-TARGET_005fLEGITIMATE_005fADDRESS_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_LEGITIMATE_ADDRESS_P</strong> <em>(machine_mode <var>mode</var>, rtx <var>x</var>, bool <var>strict</var>)</em></dt>
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<dd><p>A function that returns whether <var>x</var> (an RTX) is a legitimate memory
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address on the target machine for a memory operand of mode <var>mode</var>.
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</p>
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<p>Legitimate addresses are defined in two variants: a strict variant and a
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non-strict one. The <var>strict</var> parameter chooses which variant is
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desired by the caller.
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</p>
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<p>The strict variant is used in the reload pass. It must be defined so
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that any pseudo-register that has not been allocated a hard register is
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considered a memory reference. This is because in contexts where some
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kind of register is required, a pseudo-register with no hard register
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must be rejected. For non-hard registers, the strict variant should look
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up the <code>reg_renumber</code> array; it should then proceed using the hard
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register number in the array, or treat the pseudo as a memory reference
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if the array holds <code>-1</code>.
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</p>
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<p>The non-strict variant is used in other passes. It must be defined to
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accept all pseudo-registers in every context where some kind of
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register is required.
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</p>
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<p>Normally, constant addresses which are the sum of a <code>symbol_ref</code>
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and an integer are stored inside a <code>const</code> RTX to mark them as
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constant. Therefore, there is no need to recognize such sums
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specifically as legitimate addresses. Normally you would simply
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recognize any <code>const</code> as legitimate.
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</p>
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<p>Usually <code>PRINT_OPERAND_ADDRESS</code> is not prepared to handle constant
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sums that are not marked with <code>const</code>. It assumes that a naked
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<code>plus</code> indicates indexing. If so, then you <em>must</em> reject such
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naked constant sums as illegitimate addresses, so that none of them will
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be given to <code>PRINT_OPERAND_ADDRESS</code>.
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</p>
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<a name="index-TARGET_005fENCODE_005fSECTION_005fINFO-and-address-validation"></a>
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<p>On some machines, whether a symbolic address is legitimate depends on
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the section that the address refers to. On these machines, define the
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target hook <code>TARGET_ENCODE_SECTION_INFO</code> to store the information
|
into the <code>symbol_ref</code>, and then check for it here. When you see a
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<code>const</code>, you will have to look inside it to find the
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<code>symbol_ref</code> in order to determine the section. See <a href="Assembler-Format.html#Assembler-Format">Assembler Format</a>.
|
</p>
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<a name="index-GO_005fIF_005fLEGITIMATE_005fADDRESS"></a>
|
<p>Some ports are still using a deprecated legacy substitute for
|
this hook, the <code>GO_IF_LEGITIMATE_ADDRESS</code> macro. This macro
|
has this syntax:
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</p>
|
<div class="example">
|
<pre class="example">#define GO_IF_LEGITIMATE_ADDRESS (<var>mode</var>, <var>x</var>, <var>label</var>)
|
</pre></div>
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<p>and should <code>goto <var>label</var></code> if the address <var>x</var> is a valid
|
address on the target machine for a memory operand of mode <var>mode</var>.
|
</p>
|
<a name="index-REG_005fOK_005fSTRICT"></a>
|
<p>Compiler source files that want to use the strict variant of this
|
macro define the macro <code>REG_OK_STRICT</code>. You should use an
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<code>#ifdef REG_OK_STRICT</code> conditional to define the strict variant in
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that case and the non-strict variant otherwise.
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</p>
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<p>Using the hook is usually simpler because it limits the number of
|
files that are recompiled when changes are made.
|
</p></dd></dl>
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<dl>
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<dt><a name="index-TARGET_005fMEM_005fCONSTRAINT"></a>Macro: <strong>TARGET_MEM_CONSTRAINT</strong></dt>
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<dd><p>A single character to be used instead of the default <code>'m'</code>
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character for general memory addresses. This defines the constraint
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letter which matches the memory addresses accepted by
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<code>TARGET_LEGITIMATE_ADDRESS_P</code>. Define this macro if you want to
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support new address formats in your back end without changing the
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semantics of the <code>'m'</code> constraint. This is necessary in order to
|
preserve functionality of inline assembly constructs using the
|
<code>'m'</code> constraint.
|
</p></dd></dl>
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|
<dl>
|
<dt><a name="index-FIND_005fBASE_005fTERM"></a>Macro: <strong>FIND_BASE_TERM</strong> <em>(<var>x</var>)</em></dt>
|
<dd><p>A C expression to determine the base term of address <var>x</var>,
|
or to provide a simplified version of <var>x</var> from which <samp>alias.c</samp>
|
can easily find the base term. This macro is used in only two places:
|
<code>find_base_value</code> and <code>find_base_term</code> in <samp>alias.c</samp>.
|
</p>
|
<p>It is always safe for this macro to not be defined. It exists so
|
that alias analysis can understand machine-dependent addresses.
|
</p>
|
<p>The typical use of this macro is to handle addresses containing
|
a label_ref or symbol_ref within an UNSPEC.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fLEGITIMIZE_005fADDRESS"></a>Target Hook: <em>rtx</em> <strong>TARGET_LEGITIMIZE_ADDRESS</strong> <em>(rtx <var>x</var>, rtx <var>oldx</var>, machine_mode <var>mode</var>)</em></dt>
|
<dd><p>This hook is given an invalid memory address <var>x</var> for an
|
operand of mode <var>mode</var> and should try to return a valid memory
|
address.
|
</p>
|
<a name="index-break_005fout_005fmemory_005frefs"></a>
|
<p><var>x</var> will always be the result of a call to <code>break_out_memory_refs</code>,
|
and <var>oldx</var> will be the operand that was given to that function to produce
|
<var>x</var>.
|
</p>
|
<p>The code of the hook should not alter the substructure of
|
<var>x</var>. If it transforms <var>x</var> into a more legitimate form, it
|
should return the new <var>x</var>.
|
</p>
|
<p>It is not necessary for this hook to come up with a legitimate address,
|
with the exception of native TLS addresses (see <a href="Emulated-TLS.html#Emulated-TLS">Emulated TLS</a>).
|
The compiler has standard ways of doing so in all cases. In fact, if
|
the target supports only emulated TLS, it
|
is safe to omit this hook or make it return <var>x</var> if it cannot find
|
a valid way to legitimize the address. But often a machine-dependent
|
strategy can generate better code.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-LEGITIMIZE_005fRELOAD_005fADDRESS"></a>Macro: <strong>LEGITIMIZE_RELOAD_ADDRESS</strong> <em>(<var>x</var>, <var>mode</var>, <var>opnum</var>, <var>type</var>, <var>ind_levels</var>, <var>win</var>)</em></dt>
|
<dd><p>A C compound statement that attempts to replace <var>x</var>, which is an address
|
that needs reloading, with a valid memory address for an operand of mode
|
<var>mode</var>. <var>win</var> will be a C statement label elsewhere in the code.
|
It is not necessary to define this macro, but it might be useful for
|
performance reasons.
|
</p>
|
<p>For example, on the i386, it is sometimes possible to use a single
|
reload register instead of two by reloading a sum of two pseudo
|
registers into a register. On the other hand, for number of RISC
|
processors offsets are limited so that often an intermediate address
|
needs to be generated in order to address a stack slot. By defining
|
<code>LEGITIMIZE_RELOAD_ADDRESS</code> appropriately, the intermediate addresses
|
generated for adjacent some stack slots can be made identical, and thus
|
be shared.
|
</p>
|
<p><em>Note</em>: This macro should be used with caution. It is necessary
|
to know something of how reload works in order to effectively use this,
|
and it is quite easy to produce macros that build in too much knowledge
|
of reload internals.
|
</p>
|
<p><em>Note</em>: This macro must be able to reload an address created by a
|
previous invocation of this macro. If it fails to handle such addresses
|
then the compiler may generate incorrect code or abort.
|
</p>
|
<a name="index-push_005freload"></a>
|
<p>The macro definition should use <code>push_reload</code> to indicate parts that
|
need reloading; <var>opnum</var>, <var>type</var> and <var>ind_levels</var> are usually
|
suitable to be passed unaltered to <code>push_reload</code>.
|
</p>
|
<p>The code generated by this macro must not alter the substructure of
|
<var>x</var>. If it transforms <var>x</var> into a more legitimate form, it
|
should assign <var>x</var> (which will always be a C variable) a new value.
|
This also applies to parts that you change indirectly by calling
|
<code>push_reload</code>.
|
</p>
|
<a name="index-strict_005fmemory_005faddress_005fp"></a>
|
<p>The macro definition may use <code>strict_memory_address_p</code> to test if
|
the address has become legitimate.
|
</p>
|
<a name="index-copy_005frtx"></a>
|
<p>If you want to change only a part of <var>x</var>, one standard way of doing
|
this is to use <code>copy_rtx</code>. Note, however, that it unshares only a
|
single level of rtl. Thus, if the part to be changed is not at the
|
top level, you’ll need to replace first the top level.
|
It is not necessary for this macro to come up with a legitimate
|
address; but often a machine-dependent strategy can generate better code.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fMODE_005fDEPENDENT_005fADDRESS_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_MODE_DEPENDENT_ADDRESS_P</strong> <em>(const_rtx <var>addr</var>, addr_space_t <var>addrspace</var>)</em></dt>
|
<dd><p>This hook returns <code>true</code> if memory address <var>addr</var> in address
|
space <var>addrspace</var> can have
|
different meanings depending on the machine mode of the memory
|
reference it is used for or if the address is valid for some modes
|
but not others.
|
</p>
|
<p>Autoincrement and autodecrement addresses typically have mode-dependent
|
effects because the amount of the increment or decrement is the size
|
of the operand being addressed. Some machines have other mode-dependent
|
addresses. Many RISC machines have no mode-dependent addresses.
|
</p>
|
<p>You may assume that <var>addr</var> is a valid address for the machine.
|
</p>
|
<p>The default version of this hook returns <code>false</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fLEGITIMATE_005fCONSTANT_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_LEGITIMATE_CONSTANT_P</strong> <em>(machine_mode <var>mode</var>, rtx <var>x</var>)</em></dt>
|
<dd><p>This hook returns true if <var>x</var> is a legitimate constant for a
|
<var>mode</var>-mode immediate operand on the target machine. You can assume that
|
<var>x</var> satisfies <code>CONSTANT_P</code>, so you need not check this.
|
</p>
|
<p>The default definition returns true.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fDELEGITIMIZE_005fADDRESS"></a>Target Hook: <em>rtx</em> <strong>TARGET_DELEGITIMIZE_ADDRESS</strong> <em>(rtx <var>x</var>)</em></dt>
|
<dd><p>This hook is used to undo the possibly obfuscating effects of the
|
<code>LEGITIMIZE_ADDRESS</code> and <code>LEGITIMIZE_RELOAD_ADDRESS</code> target
|
macros. Some backend implementations of these macros wrap symbol
|
references inside an <code>UNSPEC</code> rtx to represent PIC or similar
|
addressing modes. This target hook allows GCC’s optimizers to understand
|
the semantics of these opaque <code>UNSPEC</code>s by converting them back
|
into their original form.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fCONST_005fNOT_005fOK_005fFOR_005fDEBUG_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_CONST_NOT_OK_FOR_DEBUG_P</strong> <em>(rtx <var>x</var>)</em></dt>
|
<dd><p>This hook should return true if <var>x</var> should not be emitted into
|
debug sections.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fCANNOT_005fFORCE_005fCONST_005fMEM"></a>Target Hook: <em>bool</em> <strong>TARGET_CANNOT_FORCE_CONST_MEM</strong> <em>(machine_mode <var>mode</var>, rtx <var>x</var>)</em></dt>
|
<dd><p>This hook should return true if <var>x</var> is of a form that cannot (or
|
should not) be spilled to the constant pool. <var>mode</var> is the mode
|
of <var>x</var>.
|
</p>
|
<p>The default version of this hook returns false.
|
</p>
|
<p>The primary reason to define this hook is to prevent reload from
|
deciding that a non-legitimate constant would be better reloaded
|
from the constant pool instead of spilling and reloading a register
|
holding the constant. This restriction is often true of addresses
|
of TLS symbols for various targets.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fUSE_005fBLOCKS_005fFOR_005fCONSTANT_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_USE_BLOCKS_FOR_CONSTANT_P</strong> <em>(machine_mode <var>mode</var>, const_rtx <var>x</var>)</em></dt>
|
<dd><p>This hook should return true if pool entries for constant <var>x</var> can
|
be placed in an <code>object_block</code> structure. <var>mode</var> is the mode
|
of <var>x</var>.
|
</p>
|
<p>The default version returns false for all constants.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fUSE_005fBLOCKS_005fFOR_005fDECL_005fP"></a>Target Hook: <em>bool</em> <strong>TARGET_USE_BLOCKS_FOR_DECL_P</strong> <em>(const_tree <var>decl</var>)</em></dt>
|
<dd><p>This hook should return true if pool entries for <var>decl</var> should
|
be placed in an <code>object_block</code> structure.
|
</p>
|
<p>The default version returns true for all decls.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fBUILTIN_005fRECIPROCAL"></a>Target Hook: <em>tree</em> <strong>TARGET_BUILTIN_RECIPROCAL</strong> <em>(tree <var>fndecl</var>)</em></dt>
|
<dd><p>This hook should return the DECL of a function that implements the
|
reciprocal of the machine-specific builtin function <var>fndecl</var>, or
|
<code>NULL_TREE</code> if such a function is not available.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fMASK_005fFOR_005fLOAD"></a>Target Hook: <em>tree</em> <strong>TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD</strong> <em>(void)</em></dt>
|
<dd><p>This hook should return the DECL of a function <var>f</var> that given an
|
address <var>addr</var> as an argument returns a mask <var>m</var> that can be
|
used to extract from two vectors the relevant data that resides in
|
<var>addr</var> in case <var>addr</var> is not properly aligned.
|
</p>
|
<p>The autovectorizer, when vectorizing a load operation from an address
|
<var>addr</var> that may be unaligned, will generate two vector loads from
|
the two aligned addresses around <var>addr</var>. It then generates a
|
<code>REALIGN_LOAD</code> operation to extract the relevant data from the
|
two loaded vectors. The first two arguments to <code>REALIGN_LOAD</code>,
|
<var>v1</var> and <var>v2</var>, are the two vectors, each of size <var>VS</var>, and
|
the third argument, <var>OFF</var>, defines how the data will be extracted
|
from these two vectors: if <var>OFF</var> is 0, then the returned vector is
|
<var>v2</var>; otherwise, the returned vector is composed from the last
|
<var>VS</var>-<var>OFF</var> elements of <var>v1</var> concatenated to the first
|
<var>OFF</var> elements of <var>v2</var>.
|
</p>
|
<p>If this hook is defined, the autovectorizer will generate a call
|
to <var>f</var> (using the DECL tree that this hook returns) and will
|
use the return value of <var>f</var> as the argument <var>OFF</var> to
|
<code>REALIGN_LOAD</code>. Therefore, the mask <var>m</var> returned by <var>f</var>
|
should comply with the semantics expected by <code>REALIGN_LOAD</code>
|
described above.
|
If this hook is not defined, then <var>addr</var> will be used as
|
the argument <var>OFF</var> to <code>REALIGN_LOAD</code>, in which case the low
|
log2(<var>VS</var>) - 1 bits of <var>addr</var> will be considered.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fVECTORIZATION_005fCOST"></a>Target Hook: <em>int</em> <strong>TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST</strong> <em>(enum vect_cost_for_stmt <var>type_of_cost</var>, tree <var>vectype</var>, int <var>misalign</var>)</em></dt>
|
<dd><p>Returns cost of different scalar or vector statements for vectorization cost model.
|
For vector memory operations the cost may depend on type (<var>vectype</var>) and
|
misalignment value (<var>misalign</var>).
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fVECTOR_005fALIGNMENT_005fREACHABLE"></a>Target Hook: <em>bool</em> <strong>TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE</strong> <em>(const_tree <var>type</var>, bool <var>is_packed</var>)</em></dt>
|
<dd><p>Return true if vector alignment is reachable (by peeling N iterations) for the given type.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fVEC_005fPERM_005fCONST_005fOK"></a>Target Hook: <em>bool</em> <strong>TARGET_VECTORIZE_VEC_PERM_CONST_OK</strong> <em>(machine_mode, const unsigned char *<var>sel</var>)</em></dt>
|
<dd><p>Return true if a vector created for <code>vec_perm_const</code> is valid.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fCONVERSION"></a>Target Hook: <em>tree</em> <strong>TARGET_VECTORIZE_BUILTIN_CONVERSION</strong> <em>(unsigned <var>code</var>, tree <var>dest_type</var>, tree <var>src_type</var>)</em></dt>
|
<dd><p>This hook should return the DECL of a function that implements conversion of the
|
input vector of type <var>src_type</var> to type <var>dest_type</var>.
|
The value of <var>code</var> is one of the enumerators in <code>enum tree_code</code> and
|
specifies how the conversion is to be applied
|
(truncation, rounding, etc.).
|
</p>
|
<p>If this hook is defined, the autovectorizer will use the
|
<code>TARGET_VECTORIZE_BUILTIN_CONVERSION</code> target hook when vectorizing
|
conversion. Otherwise, it will return <code>NULL_TREE</code>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fVECTORIZED_005fFUNCTION"></a>Target Hook: <em>tree</em> <strong>TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION</strong> <em>(unsigned <var>code</var>, tree <var>vec_type_out</var>, tree <var>vec_type_in</var>)</em></dt>
|
<dd><p>This hook should return the decl of a function that implements the
|
vectorized variant of the function with the <code>combined_fn</code> code
|
<var>code</var> or <code>NULL_TREE</code> if such a function is not available.
|
The return type of the vectorized function shall be of vector type
|
<var>vec_type_out</var> and the argument types should be <var>vec_type_in</var>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fMD_005fVECTORIZED_005fFUNCTION"></a>Target Hook: <em>tree</em> <strong>TARGET_VECTORIZE_BUILTIN_MD_VECTORIZED_FUNCTION</strong> <em>(tree <var>fndecl</var>, tree <var>vec_type_out</var>, tree <var>vec_type_in</var>)</em></dt>
|
<dd><p>This hook should return the decl of a function that implements the
|
vectorized variant of target built-in function <code>fndecl</code>. The
|
return type of the vectorized function shall be of vector type
|
<var>vec_type_out</var> and the argument types should be <var>vec_type_in</var>.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fSUPPORT_005fVECTOR_005fMISALIGNMENT"></a>Target Hook: <em>bool</em> <strong>TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT</strong> <em>(machine_mode <var>mode</var>, const_tree <var>type</var>, int <var>misalignment</var>, bool <var>is_packed</var>)</em></dt>
|
<dd><p>This hook should return true if the target supports misaligned vector
|
store/load of a specific factor denoted in the <var>misalignment</var>
|
parameter. The vector store/load should be of machine mode <var>mode</var> and
|
the elements in the vectors should be of type <var>type</var>. <var>is_packed</var>
|
parameter is true if the memory access is defined in a packed struct.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fPREFERRED_005fSIMD_005fMODE"></a>Target Hook: <em>machine_mode</em> <strong>TARGET_VECTORIZE_PREFERRED_SIMD_MODE</strong> <em>(machine_mode <var>mode</var>)</em></dt>
|
<dd><p>This hook should return the preferred mode for vectorizing scalar
|
mode <var>mode</var>. The default is
|
equal to <code>word_mode</code>, because the vectorizer can do some
|
transformations even in absence of specialized <acronym>SIMD</acronym> hardware.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fAUTOVECTORIZE_005fVECTOR_005fSIZES"></a>Target Hook: <em>unsigned int</em> <strong>TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_SIZES</strong> <em>(void)</em></dt>
|
<dd><p>This hook should return a mask of sizes that should be iterated over
|
after trying to autovectorize using the vector size derived from the
|
mode returned by <code>TARGET_VECTORIZE_PREFERRED_SIMD_MODE</code>.
|
The default is zero which means to not iterate over other vector sizes.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fGET_005fMASK_005fMODE"></a>Target Hook: <em>machine_mode</em> <strong>TARGET_VECTORIZE_GET_MASK_MODE</strong> <em>(unsigned <var>nunits</var>, unsigned <var>length</var>)</em></dt>
|
<dd><p>This hook returns mode to be used for a mask to be used for a vector
|
of specified <var>length</var> with <var>nunits</var> elements. By default an integer
|
vector mode of a proper size is returned.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fINIT_005fCOST"></a>Target Hook: <em>void *</em> <strong>TARGET_VECTORIZE_INIT_COST</strong> <em>(struct loop *<var>loop_info</var>)</em></dt>
|
<dd><p>This hook should initialize target-specific data structures in preparation for modeling the costs of vectorizing a loop or basic block. The default allocates three unsigned integers for accumulating costs for the prologue, body, and epilogue of the loop or basic block. If <var>loop_info</var> is non-NULL, it identifies the loop being vectorized; otherwise a single block is being vectorized.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fADD_005fSTMT_005fCOST"></a>Target Hook: <em>unsigned</em> <strong>TARGET_VECTORIZE_ADD_STMT_COST</strong> <em>(void *<var>data</var>, int <var>count</var>, enum vect_cost_for_stmt <var>kind</var>, struct _stmt_vec_info *<var>stmt_info</var>, int <var>misalign</var>, enum vect_cost_model_location <var>where</var>)</em></dt>
|
<dd><p>This hook should update the target-specific <var>data</var> in response to adding <var>count</var> copies of the given <var>kind</var> of statement to a loop or basic block. The default adds the builtin vectorizer cost for the copies of the statement to the accumulator specified by <var>where</var>, (the prologue, body, or epilogue) and returns the amount added. The return value should be viewed as a tentative cost that may later be revised.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fFINISH_005fCOST"></a>Target Hook: <em>void</em> <strong>TARGET_VECTORIZE_FINISH_COST</strong> <em>(void *<var>data</var>, unsigned *<var>prologue_cost</var>, unsigned *<var>body_cost</var>, unsigned *<var>epilogue_cost</var>)</em></dt>
|
<dd><p>This hook should complete calculations of the cost of vectorizing a loop or basic block based on <var>data</var>, and return the prologue, body, and epilogue costs as unsigned integers. The default returns the value of the three accumulators.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fDESTROY_005fCOST_005fDATA"></a>Target Hook: <em>void</em> <strong>TARGET_VECTORIZE_DESTROY_COST_DATA</strong> <em>(void *<var>data</var>)</em></dt>
|
<dd><p>This hook should release <var>data</var> and any related data structures allocated by TARGET_VECTORIZE_INIT_COST. The default releases the accumulator.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fGATHER"></a>Target Hook: <em>tree</em> <strong>TARGET_VECTORIZE_BUILTIN_GATHER</strong> <em>(const_tree <var>mem_vectype</var>, const_tree <var>index_type</var>, int <var>scale</var>)</em></dt>
|
<dd><p>Target builtin that implements vector gather operation. <var>mem_vectype</var>
|
is the vector type of the load and <var>index_type</var> is scalar type of
|
the index, scaled by <var>scale</var>.
|
The default is <code>NULL_TREE</code> which means to not vectorize gather
|
loads.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fVECTORIZE_005fBUILTIN_005fSCATTER"></a>Target Hook: <em>tree</em> <strong>TARGET_VECTORIZE_BUILTIN_SCATTER</strong> <em>(const_tree <var>vectype</var>, const_tree <var>index_type</var>, int <var>scale</var>)</em></dt>
|
<dd><p>Target builtin that implements vector scatter operation. <var>vectype</var>
|
is the vector type of the store and <var>index_type</var> is scalar type of
|
the index, scaled by <var>scale</var>.
|
The default is <code>NULL_TREE</code> which means to not vectorize scatter
|
stores.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fSIMD_005fCLONE_005fCOMPUTE_005fVECSIZE_005fAND_005fSIMDLEN"></a>Target Hook: <em>int</em> <strong>TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN</strong> <em>(struct cgraph_node *<var></var>, struct cgraph_simd_clone *<var></var>, <var>tree</var>, <var>int</var>)</em></dt>
|
<dd><p>This hook should set <var>vecsize_mangle</var>, <var>vecsize_int</var>, <var>vecsize_float</var>
|
fields in <var>simd_clone</var> structure pointed by <var>clone_info</var> argument and also
|
<var>simdlen</var> field if it was previously 0.
|
The hook should return 0 if SIMD clones shouldn’t be emitted,
|
or number of <var>vecsize_mangle</var> variants that should be emitted.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fSIMD_005fCLONE_005fADJUST"></a>Target Hook: <em>void</em> <strong>TARGET_SIMD_CLONE_ADJUST</strong> <em>(struct cgraph_node *<var></var>)</em></dt>
|
<dd><p>This hook should add implicit <code>attribute(target("..."))</code> attribute
|
to SIMD clone <var>node</var> if needed.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fSIMD_005fCLONE_005fUSABLE"></a>Target Hook: <em>int</em> <strong>TARGET_SIMD_CLONE_USABLE</strong> <em>(struct cgraph_node *<var></var>)</em></dt>
|
<dd><p>This hook should return -1 if SIMD clone <var>node</var> shouldn’t be used
|
in vectorized loops in current function, or non-negative number if it is
|
usable. In that case, the smaller the number is, the more desirable it is
|
to use it.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fGOACC_005fVALIDATE_005fDIMS"></a>Target Hook: <em>bool</em> <strong>TARGET_GOACC_VALIDATE_DIMS</strong> <em>(tree <var>decl</var>, int *<var>dims</var>, int <var>fn_level</var>)</em></dt>
|
<dd><p>This hook should check the launch dimensions provided for an OpenACC
|
compute region, or routine. Defaulted values are represented as -1
|
and non-constant values as 0. The <var>fn_level</var> is negative for the
|
function corresponding to the compute region. For a routine is is the
|
outermost level at which partitioned execution may be spawned. The hook
|
should verify non-default values. If DECL is NULL, global defaults
|
are being validated and unspecified defaults should be filled in.
|
Diagnostics should be issued as appropriate. Return
|
true, if changes have been made. You must override this hook to
|
provide dimensions larger than 1.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fGOACC_005fDIM_005fLIMIT"></a>Target Hook: <em>int</em> <strong>TARGET_GOACC_DIM_LIMIT</strong> <em>(int <var>axis</var>)</em></dt>
|
<dd><p>This hook should return the maximum size of a particular dimension,
|
or zero if unbounded.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fGOACC_005fFORK_005fJOIN"></a>Target Hook: <em>bool</em> <strong>TARGET_GOACC_FORK_JOIN</strong> <em>(gcall *<var>call</var>, const int *<var>dims</var>, bool <var>is_fork</var>)</em></dt>
|
<dd><p>This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN
|
function calls to target-specific gimple, or indicate whether they
|
should be retained. It is executed during the oacc_device_lower pass.
|
It should return true, if the call should be retained. It should
|
return false, if it is to be deleted (either because target-specific
|
gimple has been inserted before it, or there is no need for it).
|
The default hook returns false, if there are no RTL expanders for them.
|
</p></dd></dl>
|
|
<dl>
|
<dt><a name="index-TARGET_005fGOACC_005fREDUCTION"></a>Target Hook: <em>void</em> <strong>TARGET_GOACC_REDUCTION</strong> <em>(gcall *<var>call</var>)</em></dt>
|
<dd><p>This hook is used by the oacc_transform pass to expand calls to the
|
<var>GOACC_REDUCTION</var> internal function, into a sequence of gimple
|
instructions. <var>call</var> is gimple statement containing the call to
|
the function. This hook removes statement <var>call</var> after the
|
expanded sequence has been inserted. This hook is also responsible
|
for allocating any storage for reductions when necessary.
|
</p></dd></dl>
|
|
<hr>
|
<div class="header">
|
<p>
|
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