invalid SPIRV generated for frexp

[rjodinchr]

kpet/clvk#813

clspv is generating invalid SPIRV for frexp:

         %64 = OpAccessChain %_ptr_StorageBuffer__arr_uint_uint_8 %25 %uint_0 %39
         %66 = OpExtInst %float %65 Frexp %42 %64

spirv-val outputs the following error:

 error: line 106: GLSL.std.450 Frexp: expected operand Exp data type to be a 32-bit int scalar or vector type
   %66 = OpExtInst %float %65 Frexp %42 %64

Exp is a pointer on an array 8 unit, while SPIRV-Tools expects it to be a pointer on "a 32-bit int scalar of vector"