re PR tree-optimization/58978 (ICE: Segmentation fault)

	PR tree-optimization/58978
	* tree-vrp.c (all_imm_uses_in_stmt_or_feed_cond): Don't modify
	use_stmt by single_imm_use directly.  Only call single_imm_use
	on SSA_NAMEs.

	* gcc.c-torture/compile/pr58978.c: New test.

From-SVN: r204357

gcc/ChangeLog

+2013-11-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/58978
+	* tree-vrp.c (all_imm_uses_in_stmt_or_feed_cond): Don't modify
+	use_stmt by single_imm_use directly.  Only call single_imm_use
+	on SSA_NAMEs.
+
 2013-11-04  Vladimir Makarov  <vmakarov@redhat.com>
 
 	PR rtl-optimization/58968

gcc/testsuite/ChangeLog

+2013-11-04  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/58978
+	* gcc.c-torture/compile/pr58978.c: New test.
+
 2013-11-04  Paul Thomas  <pault@gcc.gnu.org>
 
 	PR fortran/57445

gcc/testsuite/gcc.c-torture/compile/pr58978.c

+/* PR tree-optimization/58978 */
+
+int
+foo (int x)
+{
+  switch (x)
+    {
+    case 0:
+    case 1:
+    case 9:
+      break;
+    default:
+      __builtin_unreachable ();
+    }
+  return x;
+}

gcc/tree-vrp.c

@@ -6472,13 +6472,14 @@ all_imm_uses_in_stmt_or_feed_cond (tree var, gimple stmt, basic_block cond_bb)
   FOR_EACH_IMM_USE_FAST (use_p, iter, var)
     if (USE_STMT (use_p) != stmt)
       {
-	gimple use_stmt = USE_STMT (use_p);
+	gimple use_stmt = USE_STMT (use_p), use_stmt2;
 	if (is_gimple_debug (use_stmt))
 	  continue;
 	while (is_gimple_assign (use_stmt)
+	       && TREE_CODE (gimple_assign_lhs (use_stmt)) == SSA_NAME
 	       && single_imm_use (gimple_assign_lhs (use_stmt),
-				  &use2_p, &use_stmt))
-	  ;
+				  &use2_p, &use_stmt2))
+	  use_stmt = use_stmt2;
 	if (gimple_code (use_stmt) != GIMPLE_COND
 	    || gimple_bb (use_stmt) != cond_bb)
 	  return false;