[committed] Fix {and,or}_comparisons_1 (PR bootstrap/49086)

[Jakub Jelinek]

Hi!

My patch apparently broke darwin bootstrap as well as Mozilla LTO build.
SSA_NAME_IS_DEFAULT_DEF has NULL gimple_bb, so dominated_by_p would
crash.  As {and,or}_var_with_comparison return NULL immediately for
SSA_NAME_IS_DEFAULT_DEF (empty stmt is not is_gimple_assign), we can return
NULL right away instead of bypassing the dominance check and then returning
NULL.

Committed as obvious to trunk/4.6.

2011-05-20  Jakub Jelinek  <ja...@redhat.com>

        PR bootstrap/49086
        * gimple-fold.c (and_comparisons_1, or_comparisons_1): Return NULL
        for PHI args that are SSA_NAME_IS_DEFAULT_DEF.

--- gcc/gimple-fold.c.jj        2011-05-20 11:05:11.000000000 +0200
+++ gcc/gimple-fold.c   2011-05-20 20:04:52.000000000 +0200
@@ -2276,7 +2276,8 @@ and_comparisons_1 (enum tree_code code1,
                                                        code2, op2a, op2b))
                        return NULL_TREE;
                    }
-                 else if (TREE_CODE (arg) == SSA_NAME)
+                 else if (TREE_CODE (arg) == SSA_NAME
+                          && !SSA_NAME_IS_DEFAULT_DEF (arg))
                    {
                      tree temp;
                      gimple def_stmt = SSA_NAME_DEF_STMT (arg);
@@ -2737,7 +2738,8 @@ or_comparisons_1 (enum tree_code code1, 
                                                        code2, op2a, op2b))
                        return NULL_TREE;
                    }
-                 else if (TREE_CODE (arg) == SSA_NAME)
+                 else if (TREE_CODE (arg) == SSA_NAME
+                          && !SSA_NAME_IS_DEFAULT_DEF (arg))
                    {
                      tree temp;
                      gimple def_stmt = SSA_NAME_DEF_STMT (arg);

        Jakub