https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111590
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Pan Li <pa...@gcc.gnu.org>: https://gcc.gnu.org/g:073849da3dfd5cabbfd4492a40a17b207b4a7630 commit r14-4291-g073849da3dfd5cabbfd4492a40a17b207b4a7630 Author: Juzhe-Zhong <juzhe.zh...@rivai.ai> Date: Wed Sep 27 06:47:12 2023 +0800 DSE: Fix ICE when the mode with access_size don't exist on the target[PR111590] hen doing fortran test with 'V' extension enabled on RISC-V port. I saw multiple ICE: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111590 The root cause is on DSE: internal compiler error: in smallest_mode_for_size, at stor-layout.cc:356 0x1918f70 smallest_mode_for_size(poly_int<2u, unsigned long>, mode_class) ../../../../gcc/gcc/stor-layout.cc:356 0x11f75bb smallest_int_mode_for_size(poly_int<2u, unsigned long>) ../../../../gcc/gcc/machmode.h:916 0x3304141 find_shift_sequence ../../../../gcc/gcc/dse.cc:1738 0x3304f1a get_stored_val ../../../../gcc/gcc/dse.cc:1906 0x3305377 replace_read ../../../../gcc/gcc/dse.cc:2010 0x3306226 check_mem_read_rtx ../../../../gcc/gcc/dse.cc:2310 0x330667b check_mem_read_use ../../../../gcc/gcc/dse.cc:2415 After investigations, DSE is trying to do optimization like this following codes: (insn 86 85 87 9 (set (reg:V4DI 168) (mem/u/c:V4DI (reg/f:DI 171) [0 S32 A128])) "bug.f90":6:18 discrim 6 1167 {*movv4di} (expr_list:REG_EQUAL (const_vector:V4DI [ (const_int 4 [0x4]) (const_int 1 [0x1]) repeated x2 (const_int 3 [0x3]) ]) (nil))) (set (mem) (reg:V4DI 168)) Then it ICE on: auto new_mode = smallest_int_mode_for_size (access_size * BITS_PER_UNIT); The access_size may be 24 or 32. We don't have such integer modes with these size so it ICE. TODO: The better way maybe make DSE use native_encode_rtx/native_decode_rtx but I don't know how to do that. So let's quickly fix this issue, we can improve the fix later. PR target/111590 gcc/ChangeLog: * dse.cc (find_shift_sequence): Check the mode with access_size exist on the target.
