Add Om1 lowering with no optimizations

tests_lit/llvm2ice_tests/alloc.ll

Index: tests_lit/llvm2ice_tests/alloc.ll
diff --git a/tests_lit/llvm2ice_tests/alloc.ll b/tests_lit/llvm2ice_tests/alloc.ll
index f7a204005dd7f2a84f69b947f5a5016786230162..2c74982c46544d9ab531d4dbdc6337bd9f0c6c7e 100644
--- a/tests_lit/llvm2ice_tests/alloc.ll
+++ b/tests_lit/llvm2ice_tests/alloc.ll
@@ -1,5 +1,9 @@
-; RUIN: %llvm2ice --verbose none %s | FileCheck %s
-; RUIN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
+; This is a basic test of the alloca instruction - one test for alloca
+; of a fixed size, and one test for variable size.
+
+; RUIN: %llvm2ice -O2 --verbose none %s | FileCheck %s
+; RUN: %llvm2ice -Om1 --verbose none %s | FileCheck --check-prefix=OPTM1 %s
+; RUN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
 ; RUN: %szdiff --llvm2ice=%llvm2ice %s | FileCheck --check-prefix=DUMP %s
 
 define void @fixed_400(i32 %n) {
@@ -8,11 +12,18 @@ entry:
   %array.asint = ptrtoint i8* %array to i32
   call void @f1(i32 %array.asint)
   ret void
-  ; CHECK:      sub     esp, 400
-  ; CHECK-NEXT: mov     eax, esp
-  ; CHECK-NEXT: push    eax
-  ; CHECK-NEXT: call    f1
 }
+; CHECK: fixed_400:
+; CHECK:      sub     esp, 400
+; CHECK-NEXT: mov     eax, esp
+; CHECK-NEXT: push    eax
+; CHECK-NEXT: call    f1
+;
+; OPTM1: fixed_400:
+; OPTM1:      sub     esp, 400
+; OPTM1-NEXT: mov     {{.*}}, esp
+; OPTM1:      push
+; OPTM1-NEXT: call    f1
 
 declare void @f1(i32)
 
@@ -22,12 +33,18 @@ entry:
   %array.asint = ptrtoint i8* %array to i32
   call void @f2(i32 %array.asint)
   ret void
-  ; CHECK:      mov     eax, dword ptr [ebp+8]
-  ; CHECK-NEXT: sub     esp, eax
-  ; CHECK-NEXT: mov     eax, esp
-  ; CHECK-NEXT: push    eax
-  ; CHECK-NEXT: call    f2
 }
+; CHECK: variable_n:
+; CHECK:      mov     eax, dword ptr [ebp+8]
+; CHECK-NEXT: sub     esp, eax
+; CHECK-NEXT: mov     eax, esp
+; CHECK-NEXT: push    eax
+; CHECK-NEXT: call    f2
+;
+; OPTM1: variable_n:
+; OPTM1:      mov     {{.*}}, esp
+; OPTM1:      push
+; OPTM1-NEXT: call    f2
 
 declare void @f2(i32)