2006-03-09 Roger Sayle <roger@eyesopen.com>

[pf3gnuchains/gcc-fork.git] / gcc / fold-const.c

diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 2e89969..be0c461 100644 (file)
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -6014,6 +6014,7 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
   tree arg01 = TREE_OPERAND (arg0, 1);
   unsigned HOST_WIDE_INT lpart;
   HOST_WIDE_INT hpart;
+  bool neg_overflow;
   int overflow;
 
   /* We have to do this the hard way to detect unsigned overflow.
@@ -6024,6 +6025,7 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
                         TREE_INT_CST_HIGH (arg1), &lpart, &hpart);
   prod = build_int_cst_wide (TREE_TYPE (arg00), lpart, hpart);
   prod = force_fit_type (prod, -1, overflow, false);
+  neg_overflow = false;
 
   if (TYPE_UNSIGNED (TREE_TYPE (arg0)))
     {
@@ -6046,6 +6048,7 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
       switch (tree_int_cst_sgn (arg1))
        {
        case -1:
+         neg_overflow = true;
          lo = int_const_binop (MINUS_EXPR, prod, tmp, 0);
          hi = prod;
          break;
@@ -6083,7 +6086,8 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
          break;
 
        case  1:
-          lo = int_const_binop (PLUS_EXPR, prod, tmp, 0);
+         neg_overflow = true;
+         lo = int_const_binop (PLUS_EXPR, prod, tmp, 0);
          hi = prod;
          break;
 
@@ -6114,22 +6118,34 @@ fold_div_compare (enum tree_code code, tree type, tree arg0, tree arg1)
 
     case LT_EXPR:
       if (TREE_OVERFLOW (lo))
-       return omit_one_operand (type, integer_one_node, arg00);
+       {
+         tmp = neg_overflow ? integer_zero_node : integer_one_node;
+         return omit_one_operand (type, tmp, arg00);
+       }
       return fold_build2 (LT_EXPR, type, arg00, lo);
 
     case LE_EXPR:
       if (TREE_OVERFLOW (hi))
-       return omit_one_operand (type, integer_one_node, arg00);
+       {
+         tmp = neg_overflow ? integer_zero_node : integer_one_node;
+         return omit_one_operand (type, tmp, arg00);
+       }
       return fold_build2 (LE_EXPR, type, arg00, hi);
 
     case GT_EXPR:
       if (TREE_OVERFLOW (hi))
-       return omit_one_operand (type, integer_zero_node, arg00);
+       {
+         tmp = neg_overflow ? integer_one_node : integer_zero_node;
+         return omit_one_operand (type, tmp, arg00);
+       }
       return fold_build2 (GT_EXPR, type, arg00, hi);
 
     case GE_EXPR:
       if (TREE_OVERFLOW (lo))
-       return omit_one_operand (type, integer_zero_node, arg00);
+       {
+         tmp = neg_overflow ? integer_one_node : integer_zero_node;
+         return omit_one_operand (type, tmp, arg00);
+       }
       return fold_build2 (GE_EXPR, type, arg00, lo);
 
     default: