Add Om1 lowering with no optimizations

tests_lit/llvm2ice_tests/struct-arith.pnacl.ll

-; RUIN: %llvm2ice -verbose inst %s | FileCheck %s
-; RUIN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
+; This test is lowered from C code that does some simple aritmetic
+; with struct members.
+
+; RUN: %llvm2ice --verbose inst %s | FileCheck %s
+; RUN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
 ; RUN: %llvm2iceinsts %s | %szdiff %s | FileCheck --check-prefix=DUMP %s
 ; RUN: %llvm2iceinsts --pnacl %s | %szdiff %s \
 ; RUN:                           | FileCheck --check-prefix=DUMP %s
 
-; This file is lowered from C code that does some simple aritmetic with
-; struct members. It's also built with the PNaCl toolchain so this is the
-; stable ABI subset of LLVM IR (structs are gone, pointers turned into i32,
-; geps gone, etc.)
-
 define internal i32 @compute_important_function(i32 %v1, i32 %v2) {
 entry:
   %__2 = inttoptr i32 %v1 to i32*
   %_v0 = load i32* %__2, align 1
 
 ; CHECK:        entry:
 ; CHECK-NEXT:       %__2 = i32 %v1
 ; CHECK-NEXT:       %_v0 = load i32* {{.*}}, align 1
 
   %__4 = inttoptr i32 %v2 to i32*
@@ skipping 26 matching lines @@
   %sub = sub i32 %add, %mul3
   %sub12 = sub i32 %sub, %mul11
   ret i32 %sub12
 
 ; CHECK:        %sub12 = sub i32 %sub, %mul11
 ; CHECK-NEXT:       ret i32 %sub12
 }
 
 ; ERRORS-NOT: ICE translation error
 ; DUMP-NOT: SZ