[Bug target/114396] New: [14] RISC-V rv64gcv vector: Runtime mismatch at -O3 with -fwrapv

[patrick at rivosinc dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114396

            Bug ID: 114396
           Summary: [14] RISC-V rv64gcv vector: Runtime mismatch at -O3
                    with -fwrapv
           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:
short a = 0xF;
short b[16];
int main() {
  for (int e = 0; e < 9; e += 1)
    b[e] = a *= 0x5;
  __builtin_printf("decimal: %d\n", a);
  __builtin_printf("hex: %X\n", a);
}

Commands:
> /scratch/tc-testing/tc-mar-18/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc 
> -march=rv64gcv -O3 red.c -o red.out -fwrapv
> /scratch/tc-testing/tc-mar-18/build-rv64gcv/bin/qemu-riscv64 red.out
decimal: 32693
hex: 7FB5
> /scratch/tc-testing/tc-mar-18/build-rv64gcv/bin/riscv64-unknown-linux-gnu-gcc 
> red.c -o red.out
> /scratch/tc-testing/tc-mar-18/build-rv64gcv/bin/qemu-riscv64 red.out
decimal: 2283
hex: 8EB

Discovered/tested using r14-9519-g3e3ad8eeb41 (not bisected)

Found using fuzzer.