[Bug target/114665] New: [14] RISC-V rv64gcv: miscompile at -O3

["patrick at rivosinc dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114665

            Bug ID: 114665
           Summary: [14] RISC-V rv64gcv: miscompile 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;
_Bool c[15][15];
int main()
{
  for (long f = 0; f < 5; ++f)
    for (long g = 0; g < 5; ++g)
      c[f][g] = 1;
  _Bool(*h)[15] = c;
  for (int f = 0; f < 15; f += 1)
    for (int g = 0; g < 15; g += 1)
      b -= c[g][g] ? c[g][g] : h[f][g];
  __builtin_printf("%X\n", b);
}

Commands:
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc -march=rv64gcv -O3 red.c -o red.out
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/qemu-riscv64 red.out
35
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc -march=rv64gcv -O2 red.c -o red.out
> /scratch/tc-testing/tc-apr-9/build-rv64gcv/bin/qemu-riscv64 red.out
FFFFFFB5

Discovered/tested using r14-9877-g1f719aa7c0d (not bisected)

Found via fuzzer.