Re: Fix PR20204

[Diego Novillo <dnovillo at redhat dot com>]

I've committed the attached to mainline and 4.0.  The only change is 
that the test now runs only on x86.  That's enough to trigger the bug.

Bootstrapped and tested x86, x86-64, ppc and ia64.


Diego.
2005-02-25  Diego Novillo  <dnovillo@redhat.com>

	PR tree-optimization/20204
	* tree-into-ssa.c (insert_phi_nodes_for): Do not use
	REWRITE_THIS_STMT markers on PHI nodes.
	(rewrite_initialize_block): Likewise.

2005-02-25  Diego Novillo  <dnovillo@redhat.com>

	PR tree-optimization/20204
	* testsuite/gcc.dg/pr20204.c: New test.

Index: tree-into-ssa.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/tree-into-ssa.c,v
retrieving revision 2.41
diff -d -u -p -r2.41 tree-into-ssa.c
--- tree-into-ssa.c	24 Feb 2005 14:18:46 -0000	2.41
+++ tree-into-ssa.c	25 Feb 2005 19:58:46 -0000
@@ -591,9 +591,6 @@ insert_phi_nodes_for (tree var, bitmap p
 	  FOR_EACH_EDGE (e, ei, bb->preds)
 	    add_phi_arg (phi, var, e);
 	}
-
-      /* Mark this PHI node as interesting for the rename process.  */
-      REWRITE_THIS_STMT (phi) = 1;
     }
 }
 
@@ -745,8 +742,7 @@ rewrite_initialize_block (struct dom_wal
   for (phi = phi_nodes (bb); phi; phi = PHI_CHAIN (phi))
     {
       tree result = PHI_RESULT (phi);
-      if (REWRITE_THIS_STMT (phi))
-	register_new_def (result, &block_defs_stack);
+      register_new_def (result, &block_defs_stack);
     }
 }
 
Index: testsuite/gcc.dg/pr20204.c
===================================================================
RCS file: testsuite/gcc.dg/pr20204.c
diff -N testsuite/gcc.dg/pr20204.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gcc.dg/pr20204.c	25 Feb 2005 19:58:55 -0000
@@ -0,0 +1,34 @@
+/* { dg-do run { target i?86-*-* } } */
+/* { dg-options "-O2" } */
+
+void *x (void *pdst, const void *psrc, unsigned int pn)
+{
+  register void *return_dst = pdst;
+  register unsigned char *dst = pdst;
+  register unsigned const char *src = psrc;
+  register int n __asm__ ("ebx") = pn;
+
+  if (src < dst && dst < src + n)
+    {
+      src += n;
+      dst += n;
+      while (n--)
+        *--dst = *--src;
+      return return_dst;
+    }
+
+  while (n >= 16) n--;
+
+  return return_dst;
+}
+extern void abort ();
+extern void exit (int);
+char xx[30] = "abc";
+int main (void)
+{
+  char yy[30] = "aab";
+
+  if (x (xx + 1, xx, 2) != xx + 1 || memcmp (xx, yy, sizeof (yy)) != 0)
+    abort ();
+  exit (0);
+}