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* [Bug target/18896] New: addressing split complex parm
@ 2004-12-09  1:45 amodra at bigpond dot net dot au
  2004-12-09  1:48 ` [Bug target/18896] " amodra at bigpond dot net dot au
                   ` (6 more replies)
  0 siblings, 7 replies; 8+ messages in thread
From: amodra at bigpond dot net dot au @ 2004-12-09  1:45 UTC (permalink / raw)
  To: gcc-bugs

On powerpc64-linux, with this testcase

int f (_Complex double a)
{
  extern _Complex double cd;
  return memcmp (&a, &cd, sizeof (a));
}

I'm hitting this assert in expand_expr_addr_expr_1

	  /* If the DECL isn't in memory, then the DECL wasn't properly
	     marked TREE_ADDRESSABLE, which will be either a front-end
	     or a tree optimizer bug.  */
	  gcc_assert (GET_CODE (result) == MEM);

The decl rtl is:

(concat:DC (mem/i:DF (reg/f:DI 113 virtual-incoming-args) [0 a+0 S8 A64])
    (reg/v:DF 119 [ a+8 ]))

That's buggy.  We shouldn't have part of the concat in memory, and part
in a reg.  Fixed with:

	* function.c (split_complex_args): Copy TREE_ADDRESSABLE for
	synthetic decl.

With that, we get 

(concat:DC (mem/i:DF (reg/f:DI 113 virtual-incoming-args) [0 a+0 S8 A64])
    (mem/i:DF (plus:DI (reg/f:DI 113 virtual-incoming-args)
            (const_int 8 [0x8])) [0 D.1119+0 S8 A64]))

Now I'm not sure where this should be fixed.  I'm guessing that the hack
I have in my local tree in expand_expr_addr_expr_1 to look inside the
CONCAT isn't the right place to fix this.  Also there's a much worse
problem;  The two pieces of the concat might not be adjacent.  Consider

int g (_Complex float a)
{
  extern _Complex float cf;
  return memcmp (&a, &cf, sizeof (a));
}

For this, the decl rtl is now

(concat:SC (mem/i:SF (reg/f:DI 113 virtual-incoming-args) [0 a+0 S4 A64])
    (mem/i:SF (plus:DI (reg/f:DI 113 virtual-incoming-args)
            (const_int 8 [0x8])) [0 D.1128+0 S4 A64]))

Notice that the two mems are 8 bytes apart but a _Complex float in
memory should have the two 4 byte parts adjacent.


Index: gcc/function.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/function.c,v
retrieving revision 1.592
diff -u -p -r1.592 function.c
--- gcc/function.c	1 Dec 2004 18:13:30 -0000	1.592
+++ gcc/function.c	9 Dec 2004 00:48:12 -0000
@@ -2061,6 +2061,7 @@ split_complex_args (tree args)
 	  /* Build a second synthetic decl.  */
 	  decl = build_decl (PARM_DECL, NULL_TREE, subtype);
 	  DECL_ARG_TYPE (decl) = DECL_ARG_TYPE (p);
+	  TREE_ADDRESSABLE (decl) = TREE_ADDRESSABLE (p);
 	  layout_decl (decl, 0);
 
 	  /* Splice it in; skip the new decl.  */

-- 
           Summary: addressing split complex parm
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: amodra at bigpond dot net dot au
                CC: gcc-bugs at gcc dot gnu dot org
GCC target triplet: powerpc64-linux


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18896


^ permalink raw reply	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2004-12-23  0:40 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-12-09  1:45 [Bug target/18896] New: addressing split complex parm amodra at bigpond dot net dot au
2004-12-09  1:48 ` [Bug target/18896] " amodra at bigpond dot net dot au
2004-12-09  5:51 ` amodra at bigpond dot net dot au
2004-12-09  6:58 ` rth at gcc dot gnu dot org
2004-12-10 14:15 ` amodra at bigpond dot net dot au
2004-12-23  0:11 ` cvs-commit at gcc dot gnu dot org
2004-12-23  0:33 ` amodra at bigpond dot net dot au
2004-12-23  0:40 ` pinskia at gcc dot gnu dot org

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