diff --git a/compiler-rt/test/dfsan/custom.cpp b/compiler-rt/test/dfsan/custom.cpp
--- a/compiler-rt/test/dfsan/custom.cpp
+++ b/compiler-rt/test/dfsan/custom.cpp
@@ -208,13 +208,13 @@
   ASSERT_LABEL(rv, dfsan_union(i_label, j_label));
 #endif
 
-  char s1[] = "ABCz";
-  char s2[] = "abcY";
-  dfsan_set_label(i_label, &s1[3], 1);
-  dfsan_set_label(j_label, &s2[3], 1);
+  char s1[] = "AbZ";
+  char s2[] = "aBy";
+  dfsan_set_label(i_label, &s1[2], 1);
+  dfsan_set_label(j_label, &s2[2], 1);
 
   rv = strcasecmp(s1, s2);
-  assert(rv > 0); // 'z' > 'Y'
+  assert(rv > 0); // 'Z' > 'y'
 #ifdef STRICT_DATA_DEPENDENCIES
   ASSERT_ZERO_LABEL(rv);
 #else
@@ -239,17 +239,17 @@
   assert(rv == 0);
   ASSERT_ZERO_LABEL(rv);
 
-  char s1[] = "ABCz";
-  char s2[] = "abcY";
-  dfsan_set_label(i_label, &s1[3], 1);
-  dfsan_set_label(j_label, &s2[3], 1);
+  char s1[] = "AbZ";
+  char s2[] = "aBy";
+  dfsan_set_label(i_label, &s1[2], 1);
+  dfsan_set_label(j_label, &s2[2], 1);
 
   rv = strncasecmp(s1, s2, 0);
   assert(rv == 0); // Compare zero chars.
   ASSERT_ZERO_LABEL(rv);
 
   rv = strncasecmp(s1, s2, 1);
-  assert(rv == 0); // 'a' == 'A'
+  assert(rv == 0); // 'A' == 'a'
   ASSERT_ZERO_LABEL(rv);
 
   rv = strncasecmp(s1, s2, 2);
@@ -257,11 +257,7 @@
   ASSERT_ZERO_LABEL(rv);
 
   rv = strncasecmp(s1, s2, 3);
-  assert(rv == 0); // 'c' == 'C'
-  ASSERT_ZERO_LABEL(rv);
-
-  rv = strncasecmp(s1, s2, 4);
-  assert(rv > 0); // 'z' > 'Y'
+  assert(rv > 0); // 'Z' > 'y'
 #ifdef STRICT_DATA_DEPENDENCIES
   ASSERT_ZERO_LABEL(rv);
 #else