Incorrect handle of bitcast instruction.

[Epeius]

Hello,
As discussed in the issue #56 , symcc aborts when executing visitBitCastInst and reports Unhandled non-pointer bit cast. I print the corresponding bitcast instruction and got %409 = bitcast <2 x i64> %408 to <4 x i32>.

For reproducing this issue, I attached the target program openjpeg.zip. The reproduce steps are:

unzip openjpeg.zip
cd openjpeg-*/
mkdir install
cd install
CC=/path/to/symcc cmake ..

The function in openjpeg that triggers this issue is opj_dwt_encode_and_deinterleave_v.

Thanks!