On 1/12/23 14:19, Richard Sandiford wrote:
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.
Ha yes, thanks for catching this!
OK otherwise, thanks. Richard
