https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113179
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by YunQiang Su <s...@gcc.gnu.org>: https://gcc.gnu.org/g:7d5d2b879ae7636ca118fb4f3a08b22705cdeacb commit r15-171-g7d5d2b879ae7636ca118fb4f3a08b22705cdeacb Author: YunQiang Su <s...@gcc.gnu.org> Date: Mon Apr 29 00:33:44 2024 +0800 expmed: TRUNCATE value1 if needed in store_bit_field_using_insv PR target/113179. In `store_bit_field_using_insv`, we just use SUBREG if value_mode >= op_mode, while in some ports, a sign_extend will be needed, such as MIPS64: If either GPR rs or GPR rt does not contain sign-extended 32-bit values (bits 63..31 equal), then the result of the operation is UNPREDICTABLE. The problem happens for the code like: struct xx { int a:4; int b:24; int c:3; int d:1; }; void xx (struct xx *a, long long b) { a->d = b; } In the above code, the hard register contains `b`, may be note well sign-extended. gcc/ PR target/113179 * expmed.cc(store_bit_field_using_insv): TRUNCATE value1 if needed. gcc/testsuite PR target/113179 * gcc.target/mips/pr113179.c: New tests.
