https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91860
--- Comment #6 from Zdenek Sojka <zsojka at seznam dot cz> --- Created attachment 46981 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46981&action=edit testcase that needs only one special compiler flag $ riscv64-unknown-linux-gnu-gcc -Og -g2 --param=max-combine-insns=3 testcase.c during RTL pass: combine testcase.c: In function 'foo': testcase.c:11:1: internal compiler error: in decompose, at rtl.h:2279 11 | } | ^ 0xd99792 wi::int_traits<std::pair<rtx_def*, machine_mode> >::decompose(long*, unsigned int, std::pair<rtx_def*, machine_mode> const&) /repo/gcc-trunk/gcc/rtl.h:2277 0xd99792 wide_int_ref_storage<false, true>::wide_int_ref_storage<std::pair<rtx_def*, machine_mode> >(std::pair<rtx_def*, machine_mode> const&) /repo/gcc-trunk/gcc/wide-int.h:1022 0xd7c745 generic_wide_int<wide_int_ref_storage<false, true> >::generic_wide_int<std::pair<rtx_def*, machine_mode> >(std::pair<rtx_def*, machine_mode> const&) /repo/gcc-trunk/gcc/wide-int.h:782 0xd7c745 simplify_const_unary_operation(rtx_code, machine_mode, rtx_def*, machine_mode) /repo/gcc-trunk/gcc/simplify-rtx.c:1900 0xd7d0fe simplify_unary_operation(rtx_code, machine_mode, rtx_def*, machine_mode) /repo/gcc-trunk/gcc/simplify-rtx.c:868 0xd80230 simplify_gen_unary(rtx_code, machine_mode, rtx_def*, machine_mode) /repo/gcc-trunk/gcc/simplify-rtx.c:367 0xd916f7 simplify_subreg(machine_mode, rtx_def*, machine_mode, poly_int<1u, unsigned long>) /repo/gcc-trunk/gcc/simplify-rtx.c:6845 0xd91ad8 simplify_gen_subreg(machine_mode, rtx_def*, machine_mode, poly_int<1u, unsigned long>) /repo/gcc-trunk/gcc/simplify-rtx.c:6873 0xd9328a simplify_replace_fn_rtx(rtx_def*, rtx_def const*, rtx_def* (*)(rtx_def*, rtx_def const*, void*), void*) /repo/gcc-trunk/gcc/simplify-rtx.c:479 0x107e560 propagate_for_debug(rtx_insn*, rtx_insn*, rtx_def*, rtx_def*, basic_block_def*) /repo/gcc-trunk/gcc/valtrack.c:219 0x1364b7b try_combine /repo/gcc-trunk/gcc/combine.c:4539 0x136a3ab combine_instructions /repo/gcc-trunk/gcc/combine.c:1326 0x136a3ab rest_of_handle_combine /repo/gcc-trunk/gcc/combine.c:15066 0x136a3ab execute /repo/gcc-trunk/gcc/combine.c:15111 Please submit a full bug report, with preprocessed source if appropriate. Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions.