[Bug target/123301] New: [Trunk] RISC-V rv64gcv: ICE at -O3 during RTL pass: expand

[xxs_chy at outlook dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123301

            Bug ID: 123301
           Summary: [Trunk] RISC-V rv64gcv: ICE at -O3 during RTL pass:
                    expand
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xxs_chy at outlook dot com
  Target Milestone: ---

Reproducer: https://godbolt.org/z/4fz4qfGcW
Testcase:
#define BS_VEC(type, num) type __attribute__((vector_size(num * sizeof(type))))
#define BITCAST(T, F, arg)                                                    
\
    ((union {                                                                 
\
        F src;                                                                
\
        T dst                                                                 
\
    })arg)                                                                    
\
        .dst
#include <riscv_bitmanip.h>
BS_VEC(uint64_t, 2)
backsmith_snippet_423(BS_VEC(int16_t, 2), BS_VEC(int32_t, 8), uint8_t)
{}
uint32_t backsmith_pure_1(BS_VEC(uint32_t, 2) BS_ARG_2, int8_t BS_ARG_3)
{
    BS_VEC(uint64_t, 4) BS_VAR_0;
    int32_t BS_VAR_4;
    uint64_t BS_TEMP_105 = 8;
    for (uint64_t BS_INC_0 = 0; BS_INC_0 < BS_TEMP_105; BS_INC_0 += 1)
        if (BS_ARG_2[1])
        {
            BS_VAR_4 = BS_INC_0;
            BS_VEC(uint32_t, 2)
            BS_TEMP_107 = __builtin_convertvector(
                (BS_VEC(int32_t, 2)){ BS_VAR_4, BS_VAR_4 },
                BS_VEC(uint32_t, 2));
            BS_VEC(uint32_t, 2)
            BS_TEMP_108 = __builtin_convertvector(
                (BS_VEC(int8_t, 2)){ BS_ARG_3 }, BS_VEC(uint32_t, 2));
            if (BITCAST(uint64_t, BS_VEC(uint32_t, 2),
                        ((BS_VEC(uint32_t, 2)){
                            BS_TEMP_107[0] ? BS_TEMP_108[0] : 0,
                            BS_TEMP_107[1] ? BS_TEMP_108[1] : 0 }))
                < backsmith_snippet_423(
                    __builtin_convertvector((BS_VEC(uint64_t, 2)){},
                                            BS_VEC(int16_t, 2)),
                    (BS_VEC(int32_t, 8)){}, 0)[1])
                BS_VAR_0 |= __builtin_convertvector(
                    (BS_VEC(int32_t, 4)){ BS_VAR_4 }, BS_VEC(uint64_t, 4));
        }
    if (BS_VAR_0[0])
        for (;;)
            ;
}

Command:
> riscv64-unknown-linux-musl-gcc -O3 -march=rv64gcv test.c

Dump:
<source>: In function 'backsmith_pure_1':
<source>:6:5: warning: no semicolon at end of struct or union
    6 |     })arg)                                                             
       \
      |     ^
<source>:28:17: note: in expansion of macro 'BITCAST'
   28 |             if (BITCAST(uint64_t, BS_VEC(uint32_t, 2),
      |                 ^~~~~~~
during RTL pass: expand
<source>:12:10: internal compiler error: Segmentation fault
   12 | uint32_t backsmith_pure_1(BS_VEC(uint32_t, 2) BS_ARG_2, int8_t
BS_ARG_3)
      |          ^~~~~~~~~~~~~~~~
0x7e0412a29e3f __libc_start_main
        ???:0
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Compiler returned: 1