llvm-project

fc69c804 - [RISCV] Implement conditional Zca implies C extension rule (#172860)

[RISCV] Implement conditional Zca implies C extension rule (#172860) This change implements the conditional "Zca implies C" rule to match GCC's behavior (PR119122) and the RISC-V specification for MISA.C. The rule is: - For RV32: - No F and no D: Zca alone implies C - F but no D: Zca + Zcf implies C - F and D: Zca + Zcf + Zcd implies C - For RV64: - No D: Zca alone implies C - D: Zca + Zcd implies C This fixes multilib matching issues where LLVM-generated march strings didn't include the C extension when GCC's multilib configurations expected it. Reference: - GCC PR119122: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119122 - RISC-V Zc spec: https://github.com/riscv/riscv-isa-manual/blob/main/src/zc.adoc Signed-off-by: Jerry Zhang Jian <jerry.zhangjian@sifive.com>