Wrap tests needing effcee inside SPIRV_EFFCEE
diff --git a/test/opt/loop_optimizations/unroll_simple.cpp b/test/opt/loop_optimizations/unroll_simple.cpp
index f551e7c..750af81 100644
--- a/test/opt/loop_optimizations/unroll_simple.cpp
+++ b/test/opt/loop_optimizations/unroll_simple.cpp
@@ -2952,6 +2952,7 @@
   EXPECT_NE(loop_2.GetLatchBlock(), loop_2.GetContinueBlock());
 }
 
+#ifdef SPIRV_EFFCEE
 // Test that a loop with a self-referencing OpPhi instruction is handled
 // correctly.
 TEST_F(PassClassTest, OpPhiSelfReference) {
@@ -2997,6 +2998,7 @@
   SinglePassRunAndMatch<opt::LoopUnroller>(text, true, kFullyUnroll,
                                            kUnrollFactor);
 }
+#endif  // SPIRV_EFFCEE
 
 }  // namespace
 }  // namespace opt
diff --git a/test/opt/pass_merge_return_test.cpp b/test/opt/pass_merge_return_test.cpp
index 3c5ff27..04ac3bf 100644
--- a/test/opt/pass_merge_return_test.cpp
+++ b/test/opt/pass_merge_return_test.cpp
@@ -516,7 +516,6 @@
   SinglePassRunAndMatch<MergeReturnPass>(before, false);
 }
 */
-#endif
 
 TEST_F(MergeReturnPassTest, StructuredControlFlowBothMergeAndHeader) {
   const std::string test =
@@ -1020,6 +1019,7 @@
 
   SinglePassRunAndMatch<MergeReturnPass>(test, false);
 }
+#endif  // SPIRV_EFFCEE
 
 }  // namespace
 }  // namespace opt