On 26/02/16 14:52, James Greenhalgh wrote:
gcc/ChangeLog:
* gcc/config/aarch64/aarch64.c (aarch64_function_arg_alignment):
Rewrite, looking one level down for records and arrays.
---
gcc/config/aarch64/aarch64.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 9142ac0..b084f83 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -1925,22 +1925,23 @@ aarch64_vfp_is_call_candidate (cumulative_args_t
pcum_v, machine_mode mode,
static unsigned int
aarch64_function_arg_alignment (machine_mode mode, const_tree type)
{
- unsigned int alignment;
+ if (!type)
+ return GET_MODE_ALIGNMENT (mode);
+ if (integer_zerop (TYPE_SIZE (type)))
+ return 0;
- if (type)
- {
- if (!integer_zerop (TYPE_SIZE (type)))
- {
- if (TYPE_MODE (type) == mode)
- alignment = TYPE_ALIGN (type);
- else
- alignment = GET_MODE_ALIGNMENT (mode);
- }
- else
- alignment = 0;
- }
- else
- alignment = GET_MODE_ALIGNMENT (mode);
+ gcc_assert (TYPE_MODE (type) == mode);
+
+ if (!AGGREGATE_TYPE_P (type))
+ return TYPE_ALIGN (TYPE_MAIN_VARIANT (type));
+
+ if (TREE_CODE (type) == ARRAY_TYPE)
+ return TYPE_ALIGN (TREE_TYPE (type));
+
+ unsigned int alignment = 0;
+
+ for (tree field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
+ alignment = std::max (alignment, DECL_ALIGN (field));
return alignment;
}
Ping.
If this is not appropriate for GCC6, then is it OK for Stage 1 of GCC 7?
I think this needs to be a GCC 7 fix at this point.
Additionally, I'd like to fully understand PR69841 before we take this
patch.
In particular, under what circumstances can the C++ front end set DECL_ALIGN
of a type to be wider than we expect. Can we ever end up with 128-bit
alignment of a template parameter when we were expecting 32- or 64-bit
alignment, and if we can what are the implications on this patch?
OK, so IIUC, we *should* be able to rely on DECL_ALIGN for the AAPCS64, as
PR/69841 occurred on gcc-5-branch because a C++ frontend change had not been
backported.
I'm not proposing to backport these AArch64 changes, hence:
Ping^2.
(For gcc 7 ?)
Also tests https://gcc.gnu.org/ml/gcc-patches/2016-01/msg01073.html .
Thanks,
Alan
