- BugFix: NEVER skip BAD nodes when creating Phi's, or data cycles loops

  can arise in dead loops. We already fixed this bug in Phi-optimization, but
  it still exists in SSA-construction, ARG!
  This fixes compilerhang5.c
- clean up if condition by using DeMorgan

[r24332]

diff --git a/ir/ir/ircons.c b/ir/ir/ircons.c
index b83715f..2d60c31 100644 (file)
--- a/ir/ir/ircons.c
+++ b/ir/ir/ircons.c
@@ -1844,7 +1844,8 @@ new_rd_Phi_in(ir_graph *irg, ir_node *block, ir_mode *mode,
        /* This loop checks whether the Phi has more than one predecessor.
           If so, it is a real Phi node and we break the loop.  Else the
           Phi node merges the same definition on several paths and therefore
-          is not needed. Don't consider Bad nodes! */
+          is not needed.
+          Note: We MUST consider Bad nodes, else we might get data flow cycles in dead loops! */
        known = res;
        for (i = ins - 1; i >= 0; --i)  {
                assert(in[i]);
@@ -1856,7 +1857,7 @@ new_rd_Phi_in(ir_graph *irg, ir_node *block, ir_mode *mode,
                if (phi0 && in[i] == phi0)
                        in[i] = res;
 
-               if (in[i] == res || in[i] == known || is_Bad(in[i]))
+               if (in[i] == res || in[i] == known)
                        continue;
 
                if (known == res)
@@ -2138,9 +2139,9 @@ phi_merge(ir_node *block, int pos, ir_mode *mode, ir_node **nin, int ins) {
           exchange phi0, as this is done in mature_immBlock(). */
        if (phi0 == NULL) {
                phi0_all = block->attr.block.graph_arr[pos];
-               if (!(is_Phi(phi0_all) &&
-                       (get_irn_arity(phi0_all) == 0)   &&
-                       (get_nodes_block(phi0_all) == block)))
+               if (! is_Phi0(phi0_all)            ||
+                   get_irn_arity(phi0_all) != 0   ||
+                   get_nodes_block(phi0_all) != block)
                        phi0_all = NULL;
        } else {
                phi0_all = phi0;