Hi,
the encoder for CONSTRUCTORs assumes that all bit-fields (DECL_BIT_FIELD) have
integral types, but that's not the case in Ada where they may have pretty much
any type, resulting in a wrong encoding for them.
The attached fix filters out non-integral bit-fields, except if they start and
end on a byte boundary because they are correctly handled in this case.
Bootstrapped/regtested on x86-64/Linux, OK for mainline and 13 branch?
2023-05-22 Eric Botcazou <ebotca...@adacore.com>
* fold-const.cc (native_encode_initializer) <CONSTRUCTOR>: Apply the
specific treatment for bit-fields only if they have an integral type
and filter out non-integral bit-fields that do not start and end on
a byte boundary.
2023-05-22 Eric Botcazou <ebotca...@adacore.com>
* gnat.dg/opt101.adb: New test.
* gnat.dg/opt101_pkg.ads: New helper.
--
Eric Botcazou
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index 25466e97220..57521501fff 100644
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -8360,20 +8360,26 @@ native_encode_initializer (tree init, unsigned char *ptr, int len,
if (fieldsize == 0)
continue;
+ /* Prepare to deal with integral bit-fields and filter out other
+ bit-fields that do not start and end on a byte boundary. */
if (DECL_BIT_FIELD (field))
{
if (!tree_fits_uhwi_p (DECL_FIELD_BIT_OFFSET (field)))
return 0;
- fieldsize = TYPE_PRECISION (TREE_TYPE (field));
bpos = tree_to_uhwi (DECL_FIELD_BIT_OFFSET (field));
- if (bpos % BITS_PER_UNIT)
- bpos %= BITS_PER_UNIT;
- else
- bpos = 0;
- fieldsize += bpos;
- epos = fieldsize % BITS_PER_UNIT;
- fieldsize += BITS_PER_UNIT - 1;
- fieldsize /= BITS_PER_UNIT;
+ if (INTEGRAL_TYPE_P (TREE_TYPE (field)))
+ {
+ bpos %= BITS_PER_UNIT;
+ fieldsize = TYPE_PRECISION (TREE_TYPE (field)) + bpos;
+ epos = fieldsize % BITS_PER_UNIT;
+ fieldsize += BITS_PER_UNIT - 1;
+ fieldsize /= BITS_PER_UNIT;
+ }
+ else if (bpos % BITS_PER_UNIT
+ || DECL_SIZE (field) == NULL_TREE
+ || !tree_fits_shwi_p (DECL_SIZE (field))
+ || tree_to_shwi (DECL_SIZE (field)) % BITS_PER_UNIT)
+ return 0;
}
if (off != -1 && pos + fieldsize <= off)
@@ -8382,7 +8388,8 @@ native_encode_initializer (tree init, unsigned char *ptr, int len,
if (val == NULL_TREE)
continue;
- if (DECL_BIT_FIELD (field))
+ if (DECL_BIT_FIELD (field)
+ && INTEGRAL_TYPE_P (TREE_TYPE (field)))
{
/* FIXME: Handle PDP endian. */
if (BYTES_BIG_ENDIAN != WORDS_BIG_ENDIAN)
-- { dg-do run }
-- { dg-options "-O" }
pragma Optimize_Alignment (Space);
with Opt101_Pkg; use Opt101_Pkg;
procedure Opt101 is
C1 : Cont1;
C2 : Cont2;
begin
C1 := ((1234, 1, 2), 1, 2);
if C1.R.I1 /= 1 or C1.I2 /= 2 then
raise Program_Error;
end if;
C2 := (1, (1234, 1, 2), 2);
if C2.R.I1 /= 1 or C2.I2 /= 2 then
raise Program_Error;
end if;
end;
package Opt101_Pkg is
type Int is mod 16;
type Rec is record
S : Short_Integer;
I1, I2 : Int;
end record;
pragma Pack (Rec);
for Rec'Alignment use 4;
type Cont1 is record
R : Rec;
I1, I2 : Int;
end record;
pragma Pack (Cont1);
type Cont2 is record
I1 : Int;
R : Rec;
I2 : Int;
end record;
pragma Pack (Cont2);
pragma No_Component_Reordering (Cont2);
end Opt101_Pkg;