Subzero: Make sure alloca with align=0 is handled correctly.

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 80bba30a56e9a832b0dca1c684ca011d907b80af..d690a19cbe85808b1f4ac0fae2039395c7d0419a 100644
--- a/tests_lit/llvm2ice_tests/alloc.ll
+++ b/tests_lit/llvm2ice_tests/alloc.ll
@@ -104,6 +104,19 @@ entry:
 ; CHECK:      mov     dword ptr [esp], eax
 ; CHECK:      call    f2
 
+; Test alloca with default (0) alignment.
+define void @align0(i32 %n) {
+entry:
+  %array = alloca i8, i32 %n
+  %__2 = ptrtoint i8* %array to i32
+  call void @f2(i32 %__2)
+  ret void
+}
+; CHECK-LABEL: align0
+; CHECK: add [[REG:.*]], 15
+; CHECK: and [[REG]], -16
+; CHECK: sub esp, [[REG]]
+
 define void @f2(i32 %ignored) {
 entry:
   ret void