[PATCH] Fix PR49876: Continue code generation with integer_zero_node on gloog_error

[Sebastian Pop]

When setting gloog_error, graphite should continue code generation
without early returns, as otherwise the SSA representation would not
be complete.  So set the new expression to integer_zero_node, that
would not require more SSA updates, and continue code generation as
nothing happened.

Regstrapping on amd64-linux.

2011-07-27  Sebastian Pop  <sebastian....@amd.com>

        PR tree-optimization/49876
        * sese.c (rename_uses): Do not return false on gloog_error: set
        the new_expr to integer_zero_node and continue code generation.
        (graphite_copy_stmts_from_block): Remove early exit on gloog_error.
---
 gcc/ChangeLog |    7 +++++++
 gcc/sese.c    |   18 ++++++++----------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b07d494..a565c18 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,12 @@
 2011-07-27  Sebastian Pop  <sebastian....@amd.com>
 
+       PR tree-optimization/49876
+       * sese.c (rename_uses): Do not return false on gloog_error: set
+       the new_expr to integer_zero_node and continue code generation.
+       (graphite_copy_stmts_from_block): Remove early exit on gloog_error.
+
+2011-07-27  Sebastian Pop  <sebastian....@amd.com>
+
        PR tree-optimization/49471
        * tree-ssa-loop-manip.c (canonicalize_loop_ivs): Build an unsigned
        iv only when the largest type is unsigned.  Do not call
diff --git a/gcc/sese.c b/gcc/sese.c
index ec96dfb..04a8e75 100644
--- a/gcc/sese.c
+++ b/gcc/sese.c
@@ -527,10 +527,10 @@ rename_uses (gimple copy, htab_t rename_map, 
gimple_stmt_iterator *gsi_tgt,
       if (chrec_contains_undetermined (scev))
        {
          *gloog_error = true;
-         return false;
+         new_expr = integer_zero_node;
        }
-
-      new_expr = chrec_apply_map (scev, iv_map);
+      else
+       new_expr = chrec_apply_map (scev, iv_map);
 
       /* The apply should produce an expression tree containing
         the uses of the new induction variables.  We should be
@@ -540,12 +540,13 @@ rename_uses (gimple copy, htab_t rename_map, 
gimple_stmt_iterator *gsi_tgt,
          || tree_contains_chrecs (new_expr, NULL))
        {
          *gloog_error = true;
-         return false;
+         new_expr = integer_zero_node;
        }
+      else
+       /* Replace the old_name with the new_expr.  */
+       new_expr = force_gimple_operand (unshare_expr (new_expr), &stmts,
+                                        true, NULL_TREE);
 
-      /* Replace the old_name with the new_expr.  */
-      new_expr = force_gimple_operand (unshare_expr (new_expr), &stmts,
-                                      true, NULL_TREE);
       gsi_insert_seq_before (gsi_tgt, stmts, GSI_SAME_STMT);
       replace_exp (use_p, new_expr);
 
@@ -621,9 +622,6 @@ graphite_copy_stmts_from_block (basic_block bb, basic_block 
new_bb,
                       gloog_error))
        fold_stmt_inplace (copy);
 
-      if (*gloog_error)
-       break;
-
       update_stmt (copy);
     }
 }
-- 
1.7.4.1