2015-05-28 Eric Botcazou <ebotcazou@adacore.com>
+ * gcc-interface/utils.c (max_size) <tcc_binary>: Add special code to
+ deal with the subtraction of a "negative" value in an unsigned type.
+
+2015-05-28 Eric Botcazou <ebotcazou@adacore.com>
+
* gcc-interface/decl.c (gnat_to_gnu_entity) <E_Subprogram_Type>: Do
not error out on a return type which has a size that overflows if the
return is done by invisible reference.
if ((code == MINUS_EXPR || code == PLUS_EXPR)
&& TREE_CODE (lhs) == INTEGER_CST
&& TREE_OVERFLOW (lhs)
- && !TREE_CONSTANT (rhs))
+ && TREE_CODE (rhs) != INTEGER_CST)
return lhs;
+ /* If we are going to subtract a "negative" value in an unsigned type,
+ do the operation as an addition of the negated value, in order to
+ avoid creating a spurious overflow below. */
+ if (code == MINUS_EXPR
+ && TYPE_UNSIGNED (type)
+ && TREE_CODE (rhs) == INTEGER_CST
+ && !TREE_OVERFLOW (rhs)
+ && tree_int_cst_sign_bit (rhs) != 0)
+ {
+ rhs = fold_build1 (NEGATE_EXPR, type, rhs);
+ code = PLUS_EXPR;
+ }
+
+ /* We need to detect overflows so we call size_binop here. */
return size_binop (code, lhs, rhs);
}
2015-05-28 Eric Botcazou <ebotcazou@adacore.com>
+ * gnat.dg/discr43.adb: New test.
+
+2015-05-28 Eric Botcazou <ebotcazou@adacore.com>
+
* gnat.dg/varsize_temp.adb: Rename into...
* gnat.dg/varsize1.adb: ...this.
* gnat.dg/varsize_copy.ad[sb]: Rename into...
--- /dev/null
+-- { dg-do compile }
+
+with Text_IO; use Text_IO;
+
+procedure Discr43 is
+
+ type Arr is array (Short_Integer range <>) of Boolean;
+
+ type Rec (LB : Short_Integer; UB : Short_Integer) is record
+ A : Arr (LB .. UB);
+ end record;
+
+begin
+ Put_Line ("Arr'Max_Size =" & Arr'Max_Size_In_Storage_Elements'Img);
+ Put_Line ("Rec'Max_Size =" & Rec'Max_Size_In_Storage_Elements'Img);
+end;