[Bug middle-end/112554] New: [14 Regression] RISC-V ICE: verify_ssa failed with -O3 --param riscv-autovec-preference=fixed-vlmax

[patrick at rivosinc dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112554

            Bug ID: 112554
           Summary: [14 Regression] RISC-V ICE: verify_ssa failed with -O3
                    --param  riscv-autovec-preference=fixed-vlmax
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: patrick at rivosinc dot com
  Target Milestone: ---

Created attachment 56597
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56597&action=edit
-freport-bug output

> ./bin/riscv64-unknown-linux-gnu-gcc -march=rv64gcv -O3 --param 
> riscv-autovec-preference=fixed-vlmax -S ../testcase.c -freport-bug
../testcase.c: In function 'b':
../testcase.c:2:6: error: missing definition
    2 | void b() {
      |      ^
for SSA_NAME: loop_len_8 in statement:
_1 = -loop_len_8;
during GIMPLE pass: vect
../testcase.c:2:6: internal compiler error: verify_ssa failed
0x14e815d verify_ssa(bool, bool)
        ../../../gcc/gcc/tree-ssa.cc:1203
0x1147735 execute_function_todo
        ../../../gcc/gcc/passes.cc:2095
0x1147b8b execute_todo
        ../../../gcc/gcc/passes.cc:2142
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
Preprocessed source stored into /tmp/ccaqTwwx.out file, please attach this to
your bugreport.

testcase:
int a;
void b() {
  unsigned long c = 18446744073709551612UL;
d:
  --c;
  a ^= c;
  if (c)
    goto d;
}

Bisected to r14-5326-gfb906061e10

-freport-bug output attached