2012-02-09  Jakub Jelinek  <jakub@redhat.com>

	Backported from mainline
	2012-01-04  Jakub Jelinek  <jakub@redhat.com>

	PR debug/51695
	* dwarf2out.c (output_loc_list): For now drop >= 64KB expressions
	in .debug_loc on the floor.

	* gcc.dg/pr51695.c: New test.

--- gcc/dwarf2out.c	(revision 182885)
+++ gcc/dwarf2out.c	(revision 182886)
@@ -11164,6 +11164,13 @@ output_loc_list (dw_loc_list_ref list_he
       /* Don't output an entry that starts and ends at the same address.  */
       if (strcmp (curr->begin, curr->end) == 0)
 	continue;
+      size = size_of_locs (curr->expr);
+      /* If the expression is too large, drop it on the floor.  We could
+	 perhaps put it into DW_TAG_dwarf_procedure and refer to that
+	 in the expression, but >= 64KB expressions for a single value
+	 in a single range are unlikely very useful.  */
+      if (size > 0xffff)
+	continue;
       if (!have_multiple_function_sections)
 	{
 	  dw2_asm_output_delta (DWARF2_ADDR_SIZE, curr->begin, curr->section,
@@ -11182,7 +11189,6 @@ output_loc_list (dw_loc_list_ref list_he
 			       "Location list end address (%s)",
 			       list_head->ll_symbol);
 	}
-      size = size_of_locs (curr->expr);
 
       /* Output the block length for this list of location operations.  */
       gcc_assert (size <= 0xffff);
--- gcc/testsuite/gcc.dg/pr51695.c	(revision 0)
+++ gcc/testsuite/gcc.dg/pr51695.c	(revision 182886)
@@ -0,0 +1,52 @@
+/* PR debug/51695 */
+/* { dg-do compile { target { int32plus } } } */
+/* { dg-options "-O2 -g" } */
+
+typedef struct
+{
+  struct { unsigned int t1, t2, t3, t4, t5, t6; } t;
+  int p;
+  struct { double X, Y, Z; } r;
+} T;
+typedef struct { T *h; } S;
+
+static unsigned int v = 0x12345678;
+
+int
+foo (void)
+{
+  v = (v & 0x80000000) ? ((v << 1) ^ 0xa398655d) : (v << 1);
+  return 0;
+}
+
+double
+bar (void)
+{
+  unsigned int o;
+  v = (v & 0x80000000) ? ((v << 1) ^ 0xa398655d) : (v << 1);
+  o = v & 0xffff;
+  return (double) o / 32768.0;
+}
+
+int
+baz (void)
+{
+  foo ();
+  return 0;
+}
+
+void
+test (S *x)
+{
+  T *t = x->h;
+  t->t.t1 = foo ();
+  t->t.t2 = foo ();
+  t->t.t3 = foo ();
+  t->t.t4 = foo ();
+  t->t.t5 = foo ();
+  t->t.t6 = foo ();
+  t->p = baz ();
+  t->r.X = bar ();
+  t->r.Y = bar ();
+  t->r.Z = bar ();
+}