Christophe Lyon <christophe.l...@arm.com> writes:
> While working on enabling DFP for AArch64, I noticed new failures in
> gcc.dg/compat/struct-layout-1.exp (t028) which were not actually
> caused by DFP types handling. These tests are generated during 'make
> check' and enabling DFP made generation different (not sure if new
> non-DFP tests are generated, or if existing ones are generated
> differently, the tests in question are huge and difficult to compare).
>
> Anyway, I reduced the problem to what I attach at the end of the new
> gcc.target/aarch64/aapcs64/va_arg-17.c test and rewrote it in the same
> scheme as other va_arg* AArch64 tests. Richard Sandiford further
> reduced this to a non-vararg function, added as a second testcase.
>
> This is a tough case mixing bit-fields and alignment, where
> aarch64_function_arg_alignment did not follow what its descriptive
> comment says: we want to use the natural alignment of the bit-field
> type only if the user didn't reduce the alignment for the bit-field
> itself.
>
> The patch also adds a comment and assert that would help someone who
> has to look at this area again.
>
> The fix would be very small, except that this introduces a new ABI
> break, and we have to warn about that. Since this actually fixes a
> problem introduced in GCC 9.1, we keep the old computation to detect
> when we now behave differently.
>
> This patch adds two new tests (va_arg-17.c and
> pr105549.c). va_arg-17.c contains the reduced offending testcase from
> struct-layout-1.exp for reference. We update some tests introduced by
> the previous patch, where parameters with bit-fields and packed
> attribute now emit a different warning.
>
> v2->v3: testcase update
>
> 2022-11-28 Christophe Lyon <christophe.l...@arm.com>
> Richard Sandiford <richard.sandif...@arm.com>
>
> gcc/
> PR target/105549
> * config/aarch64/aarch64.cc (aarch64_function_arg_alignment):
> Check DECL_PACKED for bitfield.
> (aarch64_layout_arg): Warn when parameter passing ABI changes.
> (aarch64_function_arg_boundary): Do not warn here.
> (aarch64_gimplify_va_arg_expr): Warn when parameter passing ABI
> changes.
>
> gcc/testsuite/
> PR target/105549
> * gcc.target/aarch64/bitfield-abi-warning-align16-O2.c: Update.
> * gcc.target/aarch64/bitfield-abi-warning-align16-O2-extra.c: Update.
> * gcc.target/aarch64/bitfield-abi-warning-align32-O2.c: Update.
> * gcc.target/aarch64/bitfield-abi-warning-align32-O2-extra.c: Update.
> * gcc.target/aarch64/aapcs64/va_arg-17.c: New test.
> * gcc.target/aarch64/pr105549.c: New test.
> * g++.target/aarch64/bitfield-abi-warning-align16-O2.C: Update.
> * g++.target/aarch64/bitfield-abi-warning-align16-O2-extra.C: Update.
> * g++.target/aarch64/bitfield-abi-warning-align32-O2.C: Update.
> * g++.target/aarch64/bitfield-abi-warning-align32-O2-extra.C: Update.
> ---
> gcc/config/aarch64/aarch64.cc | 148 ++++++++++++++----
> .../bitfield-abi-warning-align16-O2-extra.C | 64 ++++----
> .../aarch64/bitfield-abi-warning-align16-O2.C | 48 +++---
> .../bitfield-abi-warning-align32-O2-extra.C | 131 +++++++---------
> .../aarch64/bitfield-abi-warning-align32-O2.C | 132 ++++++++--------
> .../gcc.target/aarch64/aapcs64/va_arg-17.c | 105 +++++++++++++
> .../bitfield-abi-warning-align16-O2-extra.c | 64 ++++----
> .../aarch64/bitfield-abi-warning-align16-O2.c | 48 +++---
> .../bitfield-abi-warning-align32-O2-extra.c | 131 +++++++---------
> .../aarch64/bitfield-abi-warning-align32-O2.c | 132 ++++++++--------
> gcc/testsuite/gcc.target/aarch64/pr105549.c | 12 ++
> 11 files changed, 587 insertions(+), 428 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/aarch64/aapcs64/va_arg-17.c
> create mode 100644 gcc/testsuite/gcc.target/aarch64/pr105549.c
> [...]
> @@ -68,14 +62,14 @@
> /* { dg-note {parameter passing for argument of type 'S4' changed in GCC
> 9.1} "" { target *-*-* } 103 } f4_stdarg */
> /* { dg-note {parameter passing for argument of type 'S8' changed in GCC
> 9.1} "" { target *-*-* } 104 } f8_stdarg */
>
> -/* Parameter passing for these should not have changed in GCC 9.1 (PR
> 105549).
> +/* FIXME Parameter passing for these should not have changed in GCC 9.1 (PR
> 105549).
> Fortunately we warn. Note the discrepancy with lines 120-124 below: we
> warn
> in the callee, but not in the caller. */
Looks like a stray change. Same for the C test.
OK otherwise, thanks.
Richard
