[Bug target/114476] New: [14] RISC-V rv64gcv vector: Runtime mismatch at -O3

[patrick at rivosinc dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114476

            Bug ID: 114476
           Summary: [14] RISC-V rv64gcv vector: Runtime mismatch at -O3
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: patrick at rivosinc dot com
  Target Milestone: ---

Testcase:
signed char b = 9;
int c[23][23];
signed char d[23];
int main() {
  for (int h = 0; h < 23; h += 2) {
    c[h][h] = d[h];
    b *= 255;
  }
  __builtin_printf("%u\n", b);
}

Commands:
> /scratch/tc-testing/tc-mar-25/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc 
> -march=rv64gcv -O3 -fwrapv red.c -o red.out
> /scratch/tc-testing/tc-mar-25/build-rv64gcv/bin/qemu-riscv64 red.out
4294967287
> /scratch/tc-testing/tc-mar-25/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc 
> -march=rv64gcv -O2 -fwrapv red.c -o red.out
> /scratch/tc-testing/tc-mar-25/build-rv64gcv/bin/qemu-riscv64 red.out
9

Discovered/tested using r14-9654-g78b56a12dd0 (not bisected)

Found via fuzzer.