For targets that have extended bitints, we need to ensure these
are extended before writing to the memory, including via atomic
exchange.
gcc/c-family/ChangeLog:
* c-common.cc (resolve_overloaded_atomic_exchange): Extend
_BitInts before atomic exchange if needed.
(resolve_overloaded_atomic_compare_exchange): Same.
---
gcc/c-family/c-common.cc | 63 +++++++++++++++++++++++++++++++++++-----
1 file changed, 55 insertions(+), 8 deletions(-)
diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc
index f71cb2652d5..962e9d2a639 100644
--- a/gcc/c-family/c-common.cc
+++ b/gcc/c-family/c-common.cc
@@ -8059,11 +8059,35 @@ resolve_overloaded_atomic_exchange (location_t loc,
tree function,
/* Convert new value to required type, and dereference it.
If *p1 type can have padding or may involve floating point which
could e.g. be promoted to wider precision and demoted afterwards,
- state of padding bits might not be preserved. */
+ state of padding bits might not be preserved.
+
+ However, as a special case, we still want to preserve the padding
+ bits of _BitInt values if the ABI requires them to be extended in
+ memory. */
+
build_indirect_ref (loc, p1, RO_UNARY_STAR);
- p1 = build2_loc (loc, MEM_REF, I_type,
- build1 (VIEW_CONVERT_EXPR, I_type_ptr, p1),
- build_zero_cst (TREE_TYPE (p1)));
+
+ tree p1type = TREE_TYPE (p1);
+ bool bitint_extended_p = false;
+ if (TREE_CODE (TREE_TYPE (p1type)) == BITINT_TYPE)
+ {
+ struct bitint_info info;
+ unsigned prec = TYPE_PRECISION (TREE_TYPE (p1type));
+ targetm.c.bitint_type_info (prec, &info);
+ bitint_extended_p = info.extended;
+ }
+
+ if (bitint_extended_p)
+ p1 = fold_convert_loc (loc, I_type,
+ build2_loc (loc, MEM_REF, TREE_TYPE (p1type),
+ p1, build_zero_cst (p1type)));
+ /* Otherwise, the padding bits might not be preserved, as stated above. */
+ else
+ p1 = build2_loc (loc, MEM_REF, I_type,
+ build1 (VIEW_CONVERT_EXPR, I_type_ptr, p1),
+ build_zero_cst (p1type));
+
+
(*params)[1] = p1;
/* Move memory model to the 3rd position, and end param list. */
@@ -8143,11 +8167,34 @@ resolve_overloaded_atomic_compare_exchange (location_t
loc, tree function,
/* Convert desired value to required type, and dereference it.
If *p2 type can have padding or may involve floating point which
could e.g. be promoted to wider precision and demoted afterwards,
- state of padding bits might not be preserved. */
+ state of padding bits might not be preserved.
+
+ However, as a special case, we still want to preserve the padding
+ bits of _BitInt values if the ABI requires them to be extended in
+ memory. */
+
build_indirect_ref (loc, p2, RO_UNARY_STAR);
- p2 = build2_loc (loc, MEM_REF, I_type,
- build1 (VIEW_CONVERT_EXPR, I_type_ptr, p2),
- build_zero_cst (TREE_TYPE (p2)));
+
+ tree p2type = TREE_TYPE (p2);
+ bool bitint_extended_p = false;
+ if (TREE_CODE (TREE_TYPE (p2type)) == BITINT_TYPE)
+ {
+ struct bitint_info info;
+ unsigned prec = TYPE_PRECISION (TREE_TYPE (p2type));
+ targetm.c.bitint_type_info (prec, &info);
+ bitint_extended_p = info.extended;
+ }
+
+ if (bitint_extended_p)
+ p2 = fold_convert_loc (loc, I_type,
+ build2_loc (loc, MEM_REF, TREE_TYPE (p2type),
+ p2, build_zero_cst (p2type)));
+ /* Otherwise, the padding bits might not be preserved, as stated above. */
+ else
+ p2 = build2_loc (loc, MEM_REF, I_type,
+ build1 (VIEW_CONVERT_EXPR, I_type_ptr, p2),
+ build_zero_cst (p2type));
+
(*params)[2] = p2;
/* The rest of the parameters are fine. NULL means no special return value
--
2.46.0
