Disable Subzero IR generation for performance testing.

This CL allows one to time Subzero's bitcode parsing without IR generation
(other than types, function declarations, and uninitialized global variables)
for performance testing.

BUG=None
R=jvoung@chromium.org

Review URL: https://codereview.chromium.org/696383004

tests_lit/reader_tests/select.ll

diff --git a/tests_lit/reader_tests/select.ll b/tests_lit/reader_tests/select.ll
index 8177fa3..8421084 100644
--- a/tests_lit/reader_tests/select.ll
+++ b/tests_lit/reader_tests/select.ll
@@ -1,6 +1,10 @@
 ; Tests if we can read select instructions.
 
 ; RUN: %p2i -i %s --insts | FileCheck %s
+; RUN: %if --need=allow_disable_ir_gen --command \
+; RUN:   %p2i -i %s --args -notranslate -timing -no-ir-gen \
+; RUN: | %if --need=allow_disable_ir_gen --command \
+; RUN:   FileCheck --check-prefix=NOIR %s
 
 define void @Seli1(i32 %p) {
 entry:
@@ -293,3 +297,5 @@
 ; CHECK-NEXT:   %r = select <4 x i1> %pc, <4 x float> %pt, <4 x float> %pe
 ; CHECK-NEXT:   ret <4 x float> %r
 ; CHECK-NEXT: }
+
+; NOIR: Total across all functions