Disable Subzero IR generation for performance testing.

tests_lit/reader_tests/unreachable.ll

Index: tests_lit/reader_tests/unreachable.ll
diff --git a/tests_lit/reader_tests/unreachable.ll b/tests_lit/reader_tests/unreachable.ll
index 4cd2f9d350c702792e3551d373680773b6142d8f..56524a509b0c0d6fab6698b24eedc1065806fa08 100644
--- a/tests_lit/reader_tests/unreachable.ll
+++ b/tests_lit/reader_tests/unreachable.ll
@@ -1,6 +1,9 @@
 ; Test parsing unreachable instruction.
 
 ; RUN: %p2i -i %s --insts | FileCheck %s
+; RUN: %p2i -i %s --args -notranslate -timing -noIRgen \
+; RUN:    | %if --need=allow_disable_ir_gen \
+; RUN:      --command FileCheck --check-prefix=NOIR %s
 
 define internal i32 @divide(i32 %num, i32 %den) {
 entry:
@@ -25,3 +28,5 @@ return:                                           ; preds = %entry
 ; CHECK-NEXT:   %div = sdiv i32 %num, %den
 ; CHECK-NEXT:   ret i32 %div
 ; CHECK-NEXT: }
+
+; NOIR: Total across all functions