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utils.c (max_size): Add special code to deal with the subtraction of a "negative" value in an... 

* gcc-interface/utils.c (max_size) <tcc_binary>: Add special code to
	deal with the subtraction of a "negative" value in an unsigned type.

From-SVN: r223837
This commit is contained in:
Eric Botcazou 2015-05-28 15:45:08 +00:00 committed by Eric Botcazou
parent afd6f70235
commit 396e67d21a
4 changed files with 40 additions and 1 deletions
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5
gcc/ada/ChangeLog
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@ -1,3 +1,8 @@
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

16
gcc/ada/gcc-interface/utils.c
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@ -3443,9 +3443,23 @@ max_size (tree exp, bool max_p)
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);
}

4
gcc/testsuite/ChangeLog
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@ -1,3 +1,7 @@
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...

16
gcc/testsuite/gnat.dg/discr43.adb Normal file
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@ -0,0 +1,16 @@
-- { 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;