patch: Re: rfc: auto-casted vector types

[Aldy Hernandez]

> Is there any publicly available documentation?  My copy of the draft 
> docs
> say they are Motorola confidential.  If there is documentation 
> available,
> it would be useful to point to it somewhere.

According to Kumar, no.

> The patch looks pretty reasonable to me also.  I agree with Zack's 
> suggestions.

Done.

> It might be useful to note in the comments in the rs6000 file that the
> current implementation has a known flaw.  It pretends that V2SI is the 
> opaque
> vector type.  This means that it accidentally allows conversions 
> to/from the
> V2SI vector type without explicit casts.  In order to fix this, we 
> need to

I added a comment.

> use a different otherwise unused vector type for the opaque vector 
> type.
> Nick started on a patch to do this, but didn't have enough time to 
> finish it.

As I recall he used V8QI, but that had other problems.  V1DI, as Kumar 
suggests,
is probably a better approach, but will require heavily massaging 
spe.h/spe.md.  I'll try that later, since that will probably break 
other things I don't have time to fix right now ;-).

OK, I'm formally submitting the patch now.  I've built an spe toolchain 
with this, and a generic powerpc-linux bootstrap/regtest is in progress.

OK to install when tests finish?

Aldy

2003-02-17  Nick Clifton  <nickc@redhat.com>
	    Aldy Hernandez  <aldyh@redhat.com>

	* defaults.h (TARGET_VECTOR_TYPES_COMPATIBLE): Define.

	* doc/tm.texi: Document TARGET_VECTOR_TYPES_COMPATIBLE.

	* c-typeck.c (comptypes): Take into account
	TARGET_VECTOR_TYPES_COMPATIBLE.
	(convert_for_assignment): Same.
	(really_start_incremental_init): Disallow initialization of
	ev64_opaque types.

	* config/rs6000/rs6000-protos.h
	(rs6000_spe_vector_types_compatible): Prototype.

	* config/rs6000/rs6000.c (is_ev64_opaque_type): New.
	(rs6000_spe_vector_types_compatible): New.

	* config/rs6000/rs6000.h (TARGET_VECTOR_TYPES_COMPATIBLE): Define.

Index: defaults.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/defaults.h,v
retrieving revision 1.101
diff -c -p -r1.101 defaults.h
*** defaults.h	24 Jan 2003 22:07:00 -0000	1.101
--- defaults.h	18 Feb 2003 00:09:35 -0000
*************** You Lose!  You must define PREFERRED_DEB
*** 595,600 ****
--- 595,607 ----
   #define VECTOR_MODE_SUPPORTED_P(MODE) 0
   #endif

+ /*  Define this macro to return nonzero if no cast is needed when
+     copying a vector value of type TYPE1 to a vector value of
+     type TYPE2.  */
+ #ifndef TARGET_VECTOR_TYPES_COMPATIBLE
+ #define TARGET_VECTOR_TYPES_COMPATIBLE(TYPE1, TYPE2) 0
+ #endif
+
   /* Determine whether __cxa_atexit, rather than atexit, is used to
      register C++ destructors for local statics and global objects.  */
   #ifndef DEFAULT_USE_CXA_ATEXIT
Index: c-typeck.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/c-typeck.c,v
retrieving revision 1.218
diff -c -p -r1.218 c-typeck.c
*** c-typeck.c	1 Feb 2003 13:09:39 -0000	1.218
--- c-typeck.c	18 Feb 2003 00:09:41 -0000
*************** comptypes (type1, type2)
*** 574,579 ****
--- 574,584 ----
   	val = 1;
         break;

+     case VECTOR_TYPE:
+       /* The target might allow certain vector types to be 
compatible.  */
+       val = TARGET_VECTOR_TYPES_COMPATIBLE (t1, t2);
+       break;
+
       default:
         break;
       }
*************** convert_for_assignment (type, rhs, errty
*** 4061,4066 ****
--- 4066,4075 ----
         rhs = build1 (NOP_EXPR, type, rhs);
         return rhs;
       }
+   /* Some types can interconvert without explicit casts.  */
+   else if (codel == VECTOR_TYPE && coder == VECTOR_TYPE
+ 	   && TARGET_VECTOR_TYPES_COMPATIBLE (type, rhstype))
+     return convert (type, rhs);
     /* Arithmetic types all interconvert, and enum is treated like int. 
  */
     else if ((codel == INTEGER_TYPE || codel == REAL_TYPE
   	    || codel == ENUMERAL_TYPE || codel == COMPLEX_TYPE
Index: doc/tm.texi
===================================================================
RCS file: /cvs/gcc/gcc/gcc/doc/tm.texi,v
retrieving revision 1.198
diff -c -p -r1.198 tm.texi
*** doc/tm.texi	31 Jan 2003 23:34:17 -0000	1.198
--- doc/tm.texi	18 Feb 2003 00:10:20 -0000
*************** Define this macro to be nonzero if the p
*** 1302,1307 ****
--- 1302,1313 ----
   involving vector mode @var{mode}.  At the very least, it must have 
move
   patterns for this mode.

+ @findex TARGET_VECTOR_TYPES_COMPATIBLE
+ @item TARGET_VECTOR_TYPES_COMPATIBLE(@var{tree1}, @var{tree2})
+ Define this macro to return nonzero if no cast is needed when copying
+ a vector value of type @var{tree1} to a vector value of type
+ @var{tree2}.
+
   @findex STACK_SAVEAREA_MODE
   @item STACK_SAVEAREA_MODE (@var{save_level})
   If defined, an expression of type @code{enum machine_mode} that
Index: config/rs6000/rs6000.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.c,v
retrieving revision 1.422
diff -c -p -r1.422 rs6000.c
*** config/rs6000/rs6000.c	10 Feb 2003 18:42:19 -0000	1.422
--- config/rs6000/rs6000.c	18 Feb 2003 00:10:29 -0000
*************** static void is_altivec_return_reg PARAMS
*** 265,270 ****
--- 265,271 ----
   static rtx generate_set_vrsave PARAMS ((rtx, rs6000_stack_t *, int));
   static void altivec_frame_fixup PARAMS ((rtx, rtx, HOST_WIDE_INT));
   static int easy_vector_constant PARAMS ((rtx));
+ static int is_ev64_opaque_type PARAMS ((tree));

   /* Hash table stuff for keeping track of TOC entries.  */

*************** rs6000_memory_move_cost (mode, class, in
*** 13522,13527 ****
--- 13523,13558 ----
       return 4 * HARD_REGNO_NREGS (FIRST_ALTIVEC_REGNO, mode);
     else
       return 4 + rs6000_register_move_cost (mode, class, GENERAL_REGS);
+ }
+
+ static int
+ is_ev64_opaque_type (type)
+      tree type;
+ {
+   return (TYPE_NAME (type)
+ 	  && TREE_CODE (TYPE_NAME (type)) == TYPE_DECL
+ 	  && DECL_NAME (TYPE_NAME (type))
+ 	  && strcmp (IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))),
+ 		     "__ev64_opaque__") == 0);
+ }
+
+ /* Return true iff vector type1 can be converted into vector type2.  
*/
+
+ int
+ rs6000_spe_vector_types_compatible (t1, t2)
+      tree t1;
+      tree t2;
+ {
+   if (TREE_CODE (t1) != VECTOR_TYPE || TREE_CODE (t2) != VECTOR_TYPE)
+     return 0;
+
+   if (TYPE_NAME (t1) || TYPE_NAME (t2))
+     return is_ev64_opaque_type (t1) || is_ev64_opaque_type (t2);
+
+   /* FIXME: We assume V2SI is the opaque type, so we accidentally
+      allow inter conversion to and from V2SI modes.  We could use
+      V1D1, and rewrite <spe.h> accordingly.  */
+   return t1 == V2SI_type_node || t2 == V2SI_type_node;
   }

   #include "gt-rs6000.h"
Index: config/rs6000/rs6000.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.h,v
retrieving revision 1.251
diff -c -p -r1.251 rs6000.h
*** config/rs6000/rs6000.h	8 Feb 2003 03:59:40 -0000	1.251
--- config/rs6000/rs6000.h	18 Feb 2003 00:10:41 -0000
*************** extern int rs6000_default_long_calls;
*** 892,897 ****
--- 892,901 ----
            || (MODE) == V1DImode          \
            || (MODE) == V2SImode)

+ /* Allow SPE vector types to be inter-converted.  */
+ #define TARGET_VECTOR_TYPES_COMPATIBLE(t1,t2) \
+    (TARGET_SPE ? rs6000_spe_vector_types_compatible (t1, t2) : 0)
+
   /* Define this macro to be nonzero if the port is prepared to handle
      insns involving vector mode MODE.  At the very least, it must have
      move patterns for this mode.  */