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Re: patch: vector_size attribute


everyone's suggestions taken.

and as a bonus, we now don't allow:

	struct S { int a; };
	struct S __attribute__((vector_size(16))) foo;

i don't care if they fit in an SI, that's just plain sick ;-) and the
documentation says so.

and... the testcase triggers the errors as joseph suggested (thanks).

oh, and btw-- as per our chat, NONE of the attributes (except this one)
use types.  they all use decls, even the ones that shouldn't.  should be
fixed.

bootstrapped on x86.

how's this one?

-- 
Aldy Hernandez			E-mail: aldyh@redhat.com
Professional Gypsy
Red Hat, Inc.

2001-12-04  Aldy Hernandez  <aldyh@redhat.com>

        * extend.texi (Variable Attributes): Document vector_size.

        * gcc.dg/altivec-2.c: New.

        * attribs.c (c_common_attribute_table): Add vector_size.
	(handle_vector_size_attribute): New.

Index: attribs.c
===================================================================
RCS file: /cvs/uberbaum/gcc/attribs.c,v
retrieving revision 1.4
diff -c -p -r1.4 attribs.c
*** attribs.c	2001/11/04 02:51:21	1.4
--- attribs.c	2001/12/05 20:04:06
*************** static tree handle_no_limit_stack_attrib
*** 84,89 ****
--- 84,91 ----
  						     bool *));
  static tree handle_pure_attribute	PARAMS ((tree *, tree, tree, int,
  						 bool *));
+ static tree handle_vector_size_attribute PARAMS ((tree *, tree, tree, int,
+ 						  bool *));
  
  /* Table of machine-independent attributes common to all C-like languages.  */
  static const struct attribute_spec c_common_attribute_table[] =
*************** static const struct attribute_spec c_com
*** 139,144 ****
--- 141,148 ----
  			      handle_no_limit_stack_attribute },
    { "pure",                   0, 0, true,  false, false,
  			      handle_pure_attribute },
+   { "vector_size",	      1, 1, false, true, false,
+ 			      handle_vector_size_attribute },
    { NULL,                     0, 0, false, false, false, NULL }
  };
  
*************** handle_pure_attribute (node, name, args,
*** 1153,1158 ****
--- 1157,1230 ----
        *no_add_attrs = true;
      }
  
+   return NULL_TREE;
+ }
+ 
+ /* Handle a "vector_size" attribute; arguments as in
+    struct attribute_spec.handler.  */
+ 
+ static tree
+ handle_vector_size_attribute (node, name, args, flags, no_add_attrs)
+      tree *node;
+      tree name;
+      tree args;
+      int flags ATTRIBUTE_UNUSED;
+      bool *no_add_attrs;
+ {
+   unsigned int vecsize, nunits;
+   enum machine_mode mode, orig_mode, new_mode;
+   tree type = *node, new_type;
+ 
+   *no_add_attrs = true;
+ 
+   if (TREE_CODE (TREE_VALUE (args)) != INTEGER_CST)
+     {
+       warning ("`%s' attribute ignored", IDENTIFIER_POINTER (name));
+       return NULL_TREE;
+     }
+ 
+   /* Get the vector size (in bytes).  */
+   vecsize = TREE_INT_CST_LOW (TREE_VALUE (args));
+ 
+   /* Get the mode of the type being modified.  */
+   orig_mode = TYPE_MODE (type);
+ 
+   if (TREE_CODE (type) == RECORD_TYPE ||
+       (GET_MODE_CLASS (orig_mode) != MODE_FLOAT
+        && GET_MODE_CLASS (orig_mode) != MODE_INT))
+     {
+       error ("invalid vector type for attribute `%s'",
+ 	     IDENTIFIER_POINTER (name));
+       return NULL_TREE;
+     }
+ 
+   /* Calculate how many units fit in the vector.  */
+   nunits = vecsize / TREE_INT_CST_LOW (TYPE_SIZE_UNIT (type));
+ 
+   /* Find a suitably sized vector.  */
+   new_mode = VOIDmode;
+   for (mode = GET_CLASS_NARROWEST_MODE (GET_MODE_CLASS (orig_mode) == MODE_INT
+ 					? MODE_VECTOR_INT
+ 					: MODE_VECTOR_FLOAT);
+        mode != VOIDmode;
+        mode = GET_MODE_WIDER_MODE (mode))
+     if (vecsize == GET_MODE_SIZE (mode)	&& nunits == GET_MODE_NUNITS (mode))
+       {
+ 	new_mode = mode;
+ 	break;
+       }
+ 
+   if (new_mode == VOIDmode)
+     error ("no vector mode with the size and type specified could be found");
+   else
+     {
+       new_type = type_for_mode (new_mode, TREE_UNSIGNED (type));
+       if (!new_type)
+ 	error ("no vector mode with the size and type specified could be found");
+       else
+ 	*node = new_type;
+     }
+     
    return NULL_TREE;
  }
  
Index: testsuite/gcc.dg/altivec-2.c
===================================================================
RCS file: altivec-2.c
diff -N altivec-2.c
*** /dev/null	Tue May  5 13:32:27 1998
--- altivec-2.c	Wed Dec  5 12:04:06 2001
***************
*** 0 ****
--- 1,16 ----
+ /* { dg-do compile { target powerpc-*-* } } */
+ /* { dg-options "-maltivec" } */
+ 
+ /* Program to test the vector_size attribute.  This needs to run on a
+    target that has vectors, so use AltiVec.  */
+ 
+ #define vector __attribute__((vector_size(16)))
+ 
+ vector int foobar;
+ 
+ /* Only floats and integrals allowed.  We don't care if they map to SIs.  */
+ struct X { int frances; };
+ vector struct X hotdog;	/* { dg-bogus "invalid vector type" "case 1" } */
+ 
+ /* We don't have a V2DF.  */
+ vector double x;	/* { dg-bogus "no vector mode" "case 2" } */
Index: doc/extend.texi
===================================================================
RCS file: /cvs/uberbaum/gcc/doc/extend.texi,v
retrieving revision 1.37
diff -c -p -r1.37 extend.texi
*** extend.texi	2001/11/18 03:30:55	1.37
--- extend.texi	2001/12/05 20:04:07
*************** section.
*** 2826,2839 ****
  
  The keyword @code{__attribute__} allows you to specify special
  attributes of variables or structure fields.  This keyword is followed
! by an attribute specification inside double parentheses.  Eight
  attributes are currently defined for variables: @code{aligned},
  @code{mode}, @code{nocommon}, @code{packed}, @code{section},
! @code{transparent_union}, @code{unused}, and @code{weak}.  Some other
! attributes are defined for variables on particular target systems.  Other
! attributes are available for functions (@pxref{Function Attributes}) and
! for types (@pxref{Type Attributes}).  Other front ends might define more
! attributes (@pxref{C++ Extensions,,Extensions to the C++ Language}).
  
  You may also specify attributes with @samp{__} preceding and following
  each keyword.  This allows you to use them in header files without
--- 2826,2840 ----
  
  The keyword @code{__attribute__} allows you to specify special
  attributes of variables or structure fields.  This keyword is followed
! by an attribute specification inside double parentheses.  Nine
  attributes are currently defined for variables: @code{aligned},
  @code{mode}, @code{nocommon}, @code{packed}, @code{section},
! @code{transparent_union}, @code{unused}, @code{vector_size}, and
! @code{weak}.  Some other attributes are defined for variables on
! particular target systems.  Other attributes are available for functions
! (@pxref{Function Attributes}) and for types (@pxref{Type Attributes}).
! Other front ends might define more attributes (@pxref{C++
! Extensions,,Extensions to the C++ Language}).
  
  You may also specify attributes with @samp{__} preceding and following
  each keyword.  This allows you to use them in header files without
*************** applies to all function parameters with 
*** 3034,3039 ****
--- 3035,3065 ----
  This attribute, attached to a variable, means that the variable is meant
  to be possibly unused.  GCC will not produce a warning for this
  variable.
+ 
+ @item vector_size (@var{bytes})
+ This attribute specifies the vector size for the variable, measured in
+ bytes.  For example, the declaration:
+ 
+ @smallexample
+ int foo __attribute__ ((vector_size (16)));
+ @end smallexample
+ 
+ @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} will be V4SI@.
+ 
+ This attribute is only applicable to integral and float scalars.
+ Aggregates with this attribute are invalid, even if they are the same
+ size as a corresponding scalar.  For example, the declaration:
+ 
+ @smallexample
+ struct S { int a; };
+ struct S  __attribute__ ((vector_size (16))) foo;
+ @end smallexample
+ 
+ @noindent
+ is invalid.
  
  @item weak
  The @code{weak} attribute is described in @xref{Function Attributes}.


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