Unhandled ConstantExpr bitcast from local memory array pointer cast

[jrprice]

Reduced from OpenCL CTS vload_half test:

kernel void test( const global half *p, global float2 *f )
{
   local ushort data[2] __attribute__((aligned(sizeof(uint))));
   local half* hdata_p = (local half*) data;
   *(local uint*)&(data[0]) = 0;
   f[0] = vload_half2( 0, hdata_p );
}

clspv aborts with this error:

i32 addrspace(3)* bitcast ([2 x i16] addrspace(3)* @test.data to i32 addrspace(3)*)Unsupported Constant???
UNREACHABLE executed at ../lib/SPIRVProducerPass.cpp:2190!