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

[patrick at rivosinc dot com via Gcc-bugs]

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

--- Comment #3 from Patrick O'Neill <patrick at rivosinc dot com> ---
Created attachment 57922
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=57922&action=edit
Generated assembly files

Hmm doesn't look like it from my side - maybe there's some stack related
weirdness going on here.

Using r14-9877-g1f719aa7c0d

> cat red.c
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);
}
>  /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