https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95105
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Richard Sandiford <rsand...@gcc.gnu.org>: https://gcc.gnu.org/g:ecd56bc41563a84808fe4e1a2c7341bf8a621c92 commit r10-8436-gecd56bc41563a84808fe4e1a2c7341bf8a621c92 Author: Richard Sandiford <richard.sandif...@arm.com> Date: Wed Jul 8 14:34:11 2020 +0100 aarch64: Fix arm_sve_vector_bits on typedefs [PR95105] Compiling this testcase with -march=armv8.2-a+sve -msve-vector-bits=512: ---------------------------------------------------------- typedef __SVFloat32_t foo; typedef foo bar __attribute__((arm_sve_vector_bits(512))); template<typename T> struct s { T x; }; extern s<bar> a; bar &b = a.x; ---------------------------------------------------------- gave the bogus error: cannot bind non-const lvalue reference of type âbar&â to an rvalue of type âbarâ The testcase works if the attribute is applied directly to __SVFloat32_t instead of via foo. This shows a more general problem with the way that we were handling the arm_sve_vector_bits attribute: we started by building a distinct copy of the type to which the attribute was applied, instead of starting with its main variant. This new type then became its own main variant, meaning that the relationship between types that have the attribute could be different from the relationship between types that don't have the attribute. This patch instead copies the main variant of the original type and then reapplies all the differences. gcc/ PR target/95105 * config/aarch64/aarch64-sve-builtins.cc (handle_arm_sve_vector_bits_attribute): Create a copy of the original type's TYPE_MAIN_VARIANT, then reapply all the differences between the original type and its main variant. gcc/testsuite/ PR target/95105 * gcc.target/aarch64/sve/acle/general/attributes_8.c: New test. * g++.target/aarch64/sve/acle/general-c++/attributes_1.C: Likewise.
