2011-08-23 Richard Guenther <rguenther@suse.de>

[pf3gnuchains/gcc-fork.git] / gcc / ira-build.c

diff --git a/gcc/ira-build.c b/gcc/ira-build.c
index 09897d9..95d6c16 100644 (file)
--- a/gcc/ira-build.c
+++ b/gcc/ira-build.c
@@ -1806,6 +1806,29 @@ low_pressure_loop_node_p (ira_loop_tree_node_t node)
   return true;
 }
 
+#ifdef STACK_REGS
+/* Return TRUE if LOOP has a complex enter or exit edge.  We don't
+   form a region from such loop if the target use stack register
+   because reg-stack.c can not deal with such edges.  */
+static bool
+loop_with_complex_edge_p (struct loop *loop)
+{
+  int i;
+  edge_iterator ei;
+  edge e;
+  VEC (edge, heap) *edges;
+
+  FOR_EACH_EDGE (e, ei, loop->header->preds)
+    if (e->flags & EDGE_EH)
+      return true;
+  edges = get_loop_exit_edges (loop);
+  FOR_EACH_VEC_ELT (edge, edges, i, e)
+    if (e->flags & EDGE_COMPLEX)
+      return true;
+  return false;
+}
+#endif
+
 /* Sort loops for marking them for removal.  We put already marked
    loops first, then less frequent loops next, and then outer loops
    next.  */
@@ -1829,14 +1852,18 @@ loop_compare_func (const void *v1p, const void *v2p)
   return l1->loop->num - l2->loop->num;
 }
 
-
 /* Mark loops which should be removed from regional allocation.  We
    remove a loop with low register pressure inside another loop with
    register pressure.  In this case a separate allocation of the loop
    hardly helps (for irregular register file architecture it could
    help by choosing a better hard register in the loop but we prefer
    faster allocation even in this case).  We also remove cheap loops
-   if there are more than IRA_MAX_LOOPS_NUM of them.  */
+   if there are more than IRA_MAX_LOOPS_NUM of them.  Loop with EH
+   exit or enter edges are removed too because the allocation might
+   require put pseudo moves on the EH edges (we could still do this
+   for pseudos with caller saved hard registers in some cases but it
+   is impossible to say here or during top-down allocation pass what
+   hard register the pseudos get finally).  */
 static void
 mark_loops_for_removal (void)
 {
@@ -1859,8 +1886,12 @@ mark_loops_for_removal (void)
          }
        sorted_loops[n++] = &ira_loop_nodes[i];
        ira_loop_nodes[i].to_remove_p
-         = (low_pressure_loop_node_p (ira_loop_nodes[i].parent)
-            && low_pressure_loop_node_p (&ira_loop_nodes[i]));
+         = ((low_pressure_loop_node_p (ira_loop_nodes[i].parent)
+             && low_pressure_loop_node_p (&ira_loop_nodes[i]))
+#ifdef STACK_REGS
+            || loop_with_complex_edge_p (ira_loop_nodes[i].loop)
+#endif
+            );
       }
   qsort (sorted_loops, n, sizeof (ira_loop_tree_node_t), loop_compare_func);
   for (i = 0; n - i + 1 > IRA_MAX_LOOPS_NUM; i++)