re PR tree-optimization/44119 (error: SSA name in freelist but still referenced)

2010-05-14  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/44119
	* tree-ssa-pre.c (eliminate): Properly mark replacement of
	a PHI node necessary.

	* gcc.c-torture/compile/pr44119.c: New testcase.

From-SVN: r159412

gcc/ChangeLog

+2010-05-14  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/44119
+	* tree-ssa-pre.c (eliminate): Properly mark replacement of
+	a PHI node necessary.
+
 2010-05-14  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* tree.h (TREE_ADDRESSABLE): Remove bogus usage for FIELD_DECL.

gcc/testsuite/ChangeLog

+2010-05-14  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/44119
+	* gcc.c-torture/compile/pr44119.c: New testcase.
+
 2010-05-14  Jason Merrill  <jason@redhat.com>
 
 	PR c++/44127

gcc/testsuite/gcc.c-torture/compile/pr44119.c

+typedef signed char int8_t;
+typedef short int int16_t;
+typedef int int32_t;
+typedef unsigned int uint32_t;
+static int8_t
+safe_mul_func_int16_t_s_s (int16_t si1, int8_t si2)
+{
+  return si1 && si2 && si1 > +si2 || si1 && si2 && si2 < +si1 || si1 && si2
+    && si1 < +si2 || si1 && si2 && si1 && si2 < +si1 ? : si1 * si2;
+}
+
+struct S0
+{
+};
+int32_t g_72[7][4][1];
+int32_t *g_184 = &g_72[1][2][0];
+int32_t **g_224 = &g_184;
+struct S0 g_244 = {
+};
+
+int8_t *
+func_96 (int8_t p_97, uint32_t p_98, uint32_t p_99)
+{
+  struct S0 *l_243 = &g_244;
+  int i;
+  for (i = 0; i < 1; p_98 = 1)
+    {
+      int32_t *l_202[3];
+      int i;
+      for (i = 0; i < 1; i++)
+        l_202[i] = &g_72[2][2][0];
+      if (safe_mul_func_int16_t_s_s (0xCAF0, **g_224))
+        {
+          if (p_98 && &l_243)
+            {
+            }
+          else
+            *g_224 = l_202[0];
+          for (0;; 1)
+            {
+            }
+        }
+    }
+  return 0;
+}
+

gcc/tree-ssa-pre.c

@@ -4347,6 +4347,10 @@ eliminate (void)
 
 	  remove_phi_node (&gsi, false);
 
+	  if (!bitmap_bit_p (inserted_exprs, SSA_NAME_VERSION (res))
+	      && TREE_CODE (sprime) == SSA_NAME)
+	    gimple_set_plf (SSA_NAME_DEF_STMT (sprime), NECESSARY, true);
+
 	  if (!useless_type_conversion_p (TREE_TYPE (res), TREE_TYPE (sprime)))
 	    sprime = fold_convert (TREE_TYPE (res), sprime);
 	  stmt = gimple_build_assign (res, sprime);