X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Ftree-vrp.c;h=d487df62caa36c882c5a0e7b09044188f0b2f4cd;hb=13774f7b28a842c75a76bb2f08c448fca3bb9ca5;hp=9733a3669fb8f8ad15c9f81e1b78a51703fd7c71;hpb=820860910545844dfef72ad380727e3f3b38e196;p=pf3gnuchains%2Fgcc-fork.git

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 9733a3669fb..d487df62caa 100644
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1191,17 +1191,39 @@ vrp_int_const_binop (enum tree_code code, tree val1, tree val2)
   if (TYPE_UNSIGNED (TREE_TYPE (val1)))
     {
       int checkz = compare_values (res, val1);
+      bool overflow = false;
 
       /* Ensure that res = val1 [+*] val2 >= val1
          or that res = val1 - val2 <= val1.  */
-      if (((code == PLUS_EXPR || code == MULT_EXPR)
+      if ((code == PLUS_EXPR
 	   && !(checkz == 1 || checkz == 0))
           || (code == MINUS_EXPR
 	      && !(checkz == 0 || checkz == -1)))
 	{
+	  overflow = true;
+	}
+      /* Checking for multiplication overflow is done by dividing the
+	 output of the multiplication by the first input of the
+	 multiplication.  If the result of that division operation is
+	 not equal to the second input of the multiplication, then the
+	 multiplication overflowed.  */
+      else if (code == MULT_EXPR && !integer_zerop (val1))
+	{
+	  tree tmp = int_const_binop (TRUNC_DIV_EXPR,
+				      TYPE_MAX_VALUE (TREE_TYPE (val1)),
+				      val1, 0);
+	  int check = compare_values (tmp, val2);
+
+	  if (check != 0)
+	    overflow = true;
+	}
+
+      if (overflow)
+	{
 	  res = copy_node (res);
 	  TREE_OVERFLOW (res) = 1;
 	}
+
     }
   else if (TREE_OVERFLOW (res)
 	   && !TREE_OVERFLOW (val1)
@@ -3242,6 +3264,7 @@ remove_range_assertions (void)
     for (si = bsi_start (bb); !bsi_end_p (si);)
       {
 	tree stmt = bsi_stmt (si);
+	tree use_stmt;
 
 	if (TREE_CODE (stmt) == MODIFY_EXPR
 	    && TREE_CODE (TREE_OPERAND (stmt, 1)) == ASSERT_EXPR)
@@ -3255,11 +3278,12 @@ remove_range_assertions (void)
 
 	    /* Propagate the RHS into every use of the LHS.  */
 	    var = ASSERT_EXPR_VAR (rhs);
-	    FOR_EACH_IMM_USE_SAFE (use_p, iter, TREE_OPERAND (stmt, 0))
-	      {
-		SET_USE (use_p, var);
-		gcc_assert (TREE_CODE (var) == SSA_NAME);
-	      }
+	    FOR_EACH_IMM_USE_STMT (use_stmt, iter, TREE_OPERAND (stmt, 0))
+	      FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+		{
+		  SET_USE (use_p, var);
+		  gcc_assert (TREE_CODE (var) == SSA_NAME);
+		}
 
 	    /* And finally, remove the copy, it is not needed.  */
 	    bsi_remove (&si, true);