Add option to force filetype=asm for testing

runtime/szrt_ll.ll

 ;;===- subzero/runtime/szrt_ll.ll - Subzero runtime source ----------------===;;
 ;;
 ;;                        The Subzero Code Generator
 ;;
 ;; This file is distributed under the University of Illinois Open Source
 ;; License. See LICENSE.TXT for details.
 ;;
 ;;===----------------------------------------------------------------------===;;
 ;;
 ;; This file implements wrappers for particular bitcode instructions that are
 ;; too uncommon and complex for a particular target to bother implementing
 ;; directly in Subzero target lowering.  This needs to be compiled by some
 ;; non-Subzero compiler.
 ;;
 ;;===----------------------------------------------------------------------===;;
 
 define <4 x float> @__Sz_uitofp_4xi32_4xf32(<4 x i32> %a) {
 entry:
   %0 = uitofp <4 x i32> %a to <4 x float>
   ret <4 x float> %0
 }
 
 define <4 x i32> @__Sz_fptoui_4xi32_f32(<4 x float> %a) {
 entry:
   %0 = fptoui <4 x float> %a to <4 x i32>
   ret <4 x i32> %0
 }
 
-define i8 @__Sz_bitcast_8xi1_i8(<8 x i1> %a) {
+define i32 @__Sz_bitcast_8xi1_i8(<8 x i1> %a) {
 entry:
   %0 = bitcast <8 x i1> %a to i8
-  ret i8 %0
+  %ret = zext i8 %0 to i32
+  ret i32 %ret
 }
 
-define i16 @__Sz_bitcast_16xi1_i16(<16 x i1> %a) {
+define i32 @__Sz_bitcast_16xi1_i16(<16 x i1> %a) {
 entry:
   %0 = bitcast <16 x i1> %a to i16
-  ret i16 %0
+  %ret = zext i16 %0 to i32
+  ret i32 %ret
 }
 
 define <8 x i1> @__Sz_bitcast_i8_8xi1(i8 %a) {
 entry:
   %0 = bitcast i8 %a to <8 x i1>
   ret <8 x i1> %0
 }
 
 define <16 x i1> @__Sz_bitcast_i16_16xi1(i16 %a) {
 entry:
   %0 = bitcast i16 %a to <16 x i1>
   ret <16 x i1> %0
 }