[llvm-commits] [llvm] r137830 - in /llvm/trunk: include/llvm/MC/ lib/Target/ARM/Disassembler/ lib/Target/MBlaze/Disassembler/ lib/Target/X86/Disassembler/ test/MC/Disassembler/ARM/ tools/llvm-mc/ utils/TableGen/

[David Blaikie]

On Thu, Sep 1, 2011 at 9:38 AM, Jim Grosbach <grosbach at apple.com> wrote:
>
> Hi James,
>
> This looks a lot better, thank you.
>
>
> > +static bool Check(MCDisassembler::DecodeStatus &Out, MCDisassembler::DecodeStatus In) {
> > +  switch (In) {
> > +    case MCDisassembler::Success:
> > +      // Out stays the same.
> > +      return true;
> > +    case MCDisassembler::SoftFail:
> > +      Out = In;
> > +      return true;
> > +    case MCDisassembler::Fail:
> > +      Out = In;
> > +      return false;
> > +
> > +    default: assert(0);
>
> Should be llvm_unreachable(), not assert(0), since that's what it's semantically expressing.

I believe the usual approach in the LLVM code base is to omit the
default case if you have covered all the enumeration values and rely
on the compiler to warn if any case is omitted. By adding the default
case you thwart this warning.

- David