Initial skeleton of Subzero.

tests_lit/llvm2ice_tests/simple-loop.ll

+; RUIN: %llvm2ice -verbose inst %s | FileCheck %s
+; RUIN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
+; RUN: %szdiff --llvm2ice=%llvm2ice %s | FileCheck --check-prefix=DUMP %s
+
+define i32 @simple_loop(i32 %a, i32 %n) {
+entry:
+  %cmp4 = icmp sgt i32 %n, 0
+  br i1 %cmp4, label %for.body, label %for.end
+
+for.body:
+  %i.06 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
+  %sum.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+  %gep_array = mul i32 %i.06, 4
+  %gep = add i32 %a, %gep_array
+  %gep.asptr = inttoptr i32 %gep to i32*
+  %v0 = load i32* %gep.asptr, align 1
+  %add = add i32 %v0, %sum.05
+  %inc = add i32 %i.06, 1
+  %cmp = icmp slt i32 %inc, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.end:
+  %sum.0.lcssa = phi i32 [ 0, %entry ], [ %add, %for.body ]
+  ret i32 %sum.0.lcssa
+}
+
+; Checks for verbose instruction output
+
+; CHECK:  br i1 %cmp4, label %for.body, label %for.end
+; CHECK-NEXT: for.body
+; CHECK:  %i.06 = phi i32 [ %inc, %for.body ], [ 0, %entry ]
+; CHECK-NEXT:  %sum.05 = phi i32 [ %add, %for.body ], [ 0, %entry ]
+
+; Checks for emitted assembly
+
+; CHECK:      .globl simple_loop
+
+; CHECK:      mov ecx, dword ptr [esp+{{[0-9]+}}]
+; CHECK:      cmp ecx, 0
+; CHECK-NEXT: jg {{.*}}for.body
+; CHECK-NEXT: jmp {{.*}}for.end
+
+; TODO: the mov from ebx to esi seems redundant here - so this may need to be
+; modified later
+
+; CHECK:      add [[IREG:[a-z]+]], 1
+; CHECK-NEXT: mov [[ICMPREG:[a-z]+]], [[IREG]]
+; CHECK:      cmp [[ICMPREG]], ecx
+; CHECK-NEXT: jl {{.*}}for.body
+
+; ERRORS-NOT: ICE translation error
+; DUMP-NOT: SZ