On Wed, Jan 11, 2023 at 03:18:06PM +0100, Christophe Lyon via Gcc-patches wrote: > 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.
I'm seeing +FAIL: g++.target/aarch64/bitfield-abi-warning-align16-O2.C scan-assembler-times and\\tw0, w1, 1 10 +FAIL: g++.target/aarch64/bitfield-abi-warning-align32-O2.C scan-assembler-times and\\tw0, w1, 1 10 +FAIL: g++.target/aarch64/bitfield-abi-warning-align8-O2.C scan-assembler-times and\\tw0, w0, 1 11 +FAIL: g++.target/aarch64/bitfield-abi-warning-align8-O2.C scan-assembler-times and\\tw0, w1, 1 18 +FAIL: gcc.target/aarch64/sve/pcs/struct_3_128.c -march=armv8.2-a+sve (internal compiler error: in aarch64_layout_arg, at config/aarch64/aarch64.cc:7696) +FAIL: gcc.target/aarch64/sve/pcs/struct_3_128.c -march=armv8.2-a+sve (test for excess errors) +FAIL: gcc.target/aarch64/sve/pcs/struct_3_256.c -march=armv8.2-a+sve (internal compiler error: in aarch64_layout_arg, at config/aarch64/aarch64.cc:7696) +FAIL: gcc.target/aarch64/sve/pcs/struct_3_256.c -march=armv8.2-a+sve (test for excess errors) +FAIL: gcc.target/aarch64/sve/pcs/struct_3_512.c -march=armv8.2-a+sve (internal compiler error: in aarch64_layout_arg, at config/aarch64/aarch64.cc:7696) +FAIL: gcc.target/aarch64/sve/pcs/struct_3_512.c -march=armv8.2-a+sve (test for excess errors) regressions with this change. aarch64.cc:7696 is for me the newly added: > + gcc_assert (alignment <= 16 * BITS_PER_UNIT > + && (!alignment || abi_break < alignment) > + && (!abi_break_packed || alignment < abi_break_packed)); assert. Details in https://kojipkgs.fedoraproject.org//work/tasks/2857/96062857/build.log (configure line etc.), plus if you wget https://kojipkgs.fedoraproject.org//work/tasks/2857/96062857/build.log sed -n '/^begin /,/^end/p' build.log | uuencode you get a compressed tarball with the testsuite *.log files. Jakub
