- /* If one arg is a constant integer, put it last. */
- if (TREE_CODE (arg0) == INTEGER_CST
- && TREE_CODE (arg1) != INTEGER_CST)
- {
- TREE_OPERAND (t, 0) = arg1;
- TREE_OPERAND (t, 1) = arg0;
- arg0 = TREE_OPERAND (t, 0);
- arg1 = TREE_OPERAND (t, 1);
- code = swap_tree_comparison (code);
- TREE_SET_CODE (t, code);
+ /* If this is a comparison of a real constant with a PLUS_EXPR
+ or a MINUS_EXPR of a real constant, we can convert it into a
+ comparison with a revised real constant as long as no overflow
+ occurs when unsafe_math_optimizations are enabled. */
+ if (flag_unsafe_math_optimizations
+ && TREE_CODE (arg1) == REAL_CST
+ && (TREE_CODE (arg0) == PLUS_EXPR
+ || TREE_CODE (arg0) == MINUS_EXPR)
+ && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST
+ && 0 != (tem = const_binop (TREE_CODE (arg0) == PLUS_EXPR
+ ? MINUS_EXPR : PLUS_EXPR,
+ arg1, TREE_OPERAND (arg0, 1), 0))
+ && ! TREE_CONSTANT_OVERFLOW (tem))
+ return fold (build (code, type, TREE_OPERAND (arg0, 0), tem));