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Re: [PATCH] Add new built-in: __builtin_unreachable()


Paolo Bonzini wrote:
int f(char *f)
{
  if (*f)
    __builtin_unreachable();
  return f ? 1 : 0;
}
f:
.LFB0:
    movl    $1, %eax
    ret

Sweet. Please add this as a testcase! (Just a target dependent one for 32-bit i386, scanning the assembler for no jmp and no occurrences of %e[bs]p, will be okay).



Could you explain why it is allowed to remove the trapping instruction?


If this were java (which admittedly it is not), that would not be allowed.

David Daney


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