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extend.texi (Common Type Attributes): Document vector_size.

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gcc/ChangeLog:
	* doc/extend.texi (Common Type Attributes): Document vector_size.
	(Common Variable Attributes): Mention size constraint.  Correct
	quoting and typos.
	(Vector Extensions): Use @dfn when defining bas type.  Clarify
	base type and size constraints.

From-SVN: r269920
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Martin Sebor 2019-03-25 17:23:31 +00:00 • committed by Martin Sebor
parent bf8c1b11d5
commit 51e471ae61
2 changed files with 55 additions and 10 deletions
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12
gcc/ChangeLog
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@ -1,3 +1,11 @@
2019-03-25 Martin Sebor <msebor@redhat.com>
* doc/extend.texi (Common Type Attributes): Document vector_size.
(Common Variable Attributes): Mention size constraint. Correct
quoting and typos.
(Vector Extensions): Use @dfn when defining bas type. Clarify
base type and size constraints.
2019-03-25 Richard Biener <rguenther@suse.de>
PR tree-optimization/89789
@ -60,7 +68,7 @@
rescans. Reprocess blocks as needed, calling df_analyze before
reprocessing. Always call df_analyze before fixing up debug bind
insns.
2019-03-23 Segher Boessenkool <segher@kernel.crashing.org>
* config/rs6000/xmmintrin.h (_mm_movemask_pi8): Implement for 32-bit
@ -5203,7 +5211,7 @@
PR tree-opt/86020
Revert:
2017-05-22 Jan Hubicka <hubicka@ucw.cz>
* ipa-inline.c (edge_badness): Use inlined_time instead of
inline_summaries->get.

53
gcc/doc/extend.texi
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@ -7041,8 +7041,10 @@ class itself is instantiated.
@item vector_size (@var{bytes})
@cindex @code{vector_size} variable attribute
This attribute specifies the vector size for the variable, measured in
bytes. For example, the declaration:
This attribute specifies the vector size for the type of the declared
variable, measured in bytes. The type to which it applies is known as
the @dfn{base type}. The @var{bytes} argument must be a positive
power-of-two multiple of the base type size. For example, the declaration:
@smallexample
int foo __attribute__ ((vector_size (16)));
@ -7050,10 +7052,12 @@ int foo __attribute__ ((vector_size (16)));
@noindent
causes the compiler to set the mode for @code{foo}, to be 16 bytes,
divided into @code{int} sized units. Assuming a 32-bit int (a vector of
4 units of 4 bytes), the corresponding mode of @code{foo} is V4SI@.
divided into @code{int} sized units. Assuming a 32-bit @code{int},
@code{foo}'s type is a vector of four units of four bytes each, and
the corresponding mode of @code{foo} is @code{V4SI}.
@xref{Vector Extensions} for details of manipulating vector variables.
This attribute is only applicable to integral and float scalars,
This attribute is only applicable to integral and floating scalars,
although arrays, pointers, and function return values are allowed in
conjunction with this construct.
@ -8116,6 +8120,39 @@ the case with lock or thread classes, which are usually defined and then
not referenced, but contain constructors and destructors that have
nontrivial bookkeeping functions.
@item vector_size (@var{bytes})
@cindex @code{vector_size} type attribute
This attribute specifies the vector size for the type, measured in bytes.
The type to which it applies is known as the @dfn{base type}. The @var{bytes}
argument must be a positive power-of-two multiple of the base type size. For
example, the following declarations:
@smallexample
typedef __attribute__ ((vector_size (32))) int int_vec32_t ;
typedef __attribute__ ((vector_size (32))) int* int_vec32_ptr_t;
typedef __attribute__ ((vector_size (32))) int int_vec32_arr3_t[3];
@end smallexample
@noindent
define @code{int_vec32_t} to be a 32-byte vector type composed of @code{int}
sized units. With @code{int} having a size of 4 bytes, the type defines
a vector of eight units, four bytes each. The mode of variables of type
@code{int_vec32_t} is @code{V8SI}. @code{int_vec32_ptr_t} is then defined
to be a pointer to such a vector type, and @code{int_vec32_arr3_t} to be
an array of three such vectors. @xref{Vector Extensions} for details of
manipulating objects of vector types.
This attribute is only applicable to integral and floating scalar types.
In function declarations the attribute applies to the function return
type.
For example, the following:
@smallexample
__attribute__ ((vector_size (16))) float get_flt_vec16 (void);
@end smallexample
declares @code{get_flt_vec16} to be a function returning a 16-byte vector
with the base type @code{float}.
@item visibility
@cindex @code{visibility} type attribute
In C++, attribute visibility (@pxref{Function Attributes}) can also be
@ -10883,7 +10920,7 @@ typedef int v4si __attribute__ ((vector_size (16)));
@end smallexample
@noindent
The @code{int} type specifies the base type, while the attribute specifies
The @code{int} type specifies the @dfn{base type}, while the attribute specifies
the vector size for the variable, measured in bytes. For example, the
declaration above causes the compiler to set the mode for the @code{v4si}
type to be 16 bytes wide and divided into @code{int} sized units. For
@ -10891,9 +10928,9 @@ a 32-bit @code{int} this means a vector of 4 units of 4 bytes, and the
corresponding mode of @code{foo} is @acronym{V4SI}.
The @code{vector_size} attribute is only applicable to integral and
float scalars, although arrays, pointers, and function return values
floating scalars, although arrays, pointers, and function return values
are allowed in conjunction with this construct. Only sizes that are
a power of two are currently allowed.
positive power-of-two multiples of the base type size are currently allowed.
All the basic integer types can be used as base types, both as signed
and as unsigned: @code{char}, @code{short}, @code{int}, @code{long},