[Bug target/114352] RISC-V: ICE when __attribute__((target("arch=+v")) and build with rv64gc -O3

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114352

--- Comment #3 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Pan Li <panli@gcc.gnu.org>:

https://gcc.gnu.org/g:d3c24e9e55a7cf18df313a8b32b6de4b3ba81013

commit r14-9604-gd3c24e9e55a7cf18df313a8b32b6de4b3ba81013
Author: Pan Li <pan2.li@intel.com>
Date:   Mon Mar 18 11:21:29 2024 +0800

    RISC-V: Bugfix ICE for __attribute__((target("arch=+v"))

    This patch would like to fix one ICE for __attribute__((target("arch=+v"))
    and likewise extension(s). Given we have sample code as below:

    void __attribute__((target("arch=+v")))
    test_2 (int *a, int *b, int *out, unsigned count)
    {
      unsigned i;
      for (i = 0; i < count; i++)
       out[i] = a[i] + b[i];
    }

    It will have ICE when build with -march=rv64gc -O3.

    test.c: In function âtest_2â:
    test.c:4:1: internal compiler error: Floating point exception
    4 | {
          | ^
    0x1a5891b crash_signal
    .../__RISC-V_BUILD__/../gcc/toplev.cc:319
    0x7f0a7884251f ???
            ./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
    0x1f51ba4 riscv_hard_regno_nregs
            .../__RISC-V_BUILD__/../gcc/config/riscv/riscv.cc:8143
    0x1967bb9 init_reg_modes_target()
            .../__RISC-V_BUILD__/../gcc/reginfo.cc:471
    0x13fc029 init_emit_regs()
            .../__RISC-V_BUILD__/../gcc/emit-rtl.cc:6237
    0x1a5b83d target_reinit()
            .../__RISC-V_BUILD__/../gcc/toplev.cc:1936
    0x35e374d save_target_globals()
            .../__RISC-V_BUILD__/../gcc/target-globals.cc:92
    0x35e381f save_target_globals_default_opts()
            .../__RISC-V_BUILD__/../gcc/target-globals.cc:122
    0x1f544cc riscv_save_restore_target_globals(tree_node*)
            .../__RISC-V_BUILD__/../gcc/config/riscv/riscv.cc:9138
    0x1f55c36 riscv_set_current_function
    ...

    There are two reasons for this ICE.
    1. The implied extension(s) of v are not well handled and the
       TARGET_MIN_VLEN is 0 which is not reinitialized.  Then the
       size / TARGET_MIN_VLEN will have DivideByZero.
    2. The machine modes of the vector types will be vary after
       the v extension is introduced.

    This patch passed below testsuite:
    1. The riscv fully regression test.

            PR target/114352

    gcc/ChangeLog:

            * common/config/riscv/riscv-common.cc (riscv_subset_list::parse):
            Replace implied, combine and check to func finalize.
            (riscv_subset_list::finalize): New func impl to take care of
            implied, combine ext and related checks.
            * config/riscv/riscv-subset.h: Add func decl for finalize.
            * config/riscv/riscv-target-attr.cc
(riscv_target_attr_parser::parse_arch):
            Finalize the ext before return succeed.
            * config/riscv/riscv.cc (riscv_set_current_function): Reinit the
            machine mode before when set cur function.

    gcc/testsuite/ChangeLog:

            * gcc.target/riscv/rvv/base/pr114352-1.c: New test.
            * gcc.target/riscv/rvv/base/pr114352-2.c: New test.

    Signed-off-by: Pan Li <pan2.li@intel.com>