diff --git a/compiler-rt/test/asan/TestCases/strcasestr-1.c b/compiler-rt/test/asan/TestCases/strcasestr-1.c
index 78e14d31f278..c38871ea5362 100644
--- a/compiler-rt/test/asan/TestCases/strcasestr-1.c
+++ b/compiler-rt/test/asan/TestCases/strcasestr-1.c
@@ -11,14 +11,15 @@
 #define _GNU_SOURCE
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   char *r = 0;
   char s2[] = "c";
-  char s1[] = {'a', 'C'};
-  char s3 = 0;
+  char s1[4] = "abC";
+  __asan_poison_memory_region ((char *)&s1[2], 2);
   r = strcasestr(s1, s2);
-  // CHECK:'s{{[1|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
-  assert(r == s1 + 1);
+  // CHECK:'s1' <== Memory access at offset {{[0-9]+}} partially overflows this variable
+  assert(r == s1 + 2);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strcasestr-2.c b/compiler-rt/test/asan/TestCases/strcasestr-2.c
index 4593a143e8fb..cca6d208cd43 100644
--- a/compiler-rt/test/asan/TestCases/strcasestr-2.c
+++ b/compiler-rt/test/asan/TestCases/strcasestr-2.c
@@ -11,14 +11,15 @@
 #define _GNU_SOURCE
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   char *r = 0;
   char s1[] = "ab";
-  char s2[] = {'c'};
-  char s3 = 0;
+  char s2[4] = "cba";
+  __asan_poison_memory_region ((char *)&s2[2], 2);
   r = strcasestr(s1, s2);
   assert(r == 0);
-  // CHECK:'s{{[2|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s2' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strcspn-1.c b/compiler-rt/test/asan/TestCases/strcspn-1.c
index 04675e4b420e..6cda2e210cba 100644
--- a/compiler-rt/test/asan/TestCases/strcspn-1.c
+++ b/compiler-rt/test/asan/TestCases/strcspn-1.c
@@ -6,14 +6,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   size_t r;
   char s2[] = "ab";
-  char s1[] = {'c', 'a'};
-  char s3 = 0;
+  char s1[4] = "caB";
+  __asan_poison_memory_region ((char *)&s1[2], 2);
   r = strcspn(s1, s2);
-  // CHECK:'s{{[1|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s1' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == 1);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strcspn-2.c b/compiler-rt/test/asan/TestCases/strcspn-2.c
index e77ce6502244..8bb4b8a57eec 100644
--- a/compiler-rt/test/asan/TestCases/strcspn-2.c
+++ b/compiler-rt/test/asan/TestCases/strcspn-2.c
@@ -6,14 +6,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   size_t r;
   char s1[] = "ab";
-  char s2[] = {'a'};
-  char s3 = 0;
+  char s2[4] = "abc";
+  __asan_poison_memory_region ((char *)&s2[2], 2);
   r = strcspn(s1, s2);
-  // CHECK:'s{{[2|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s2' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == 0);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strpbrk-1.c b/compiler-rt/test/asan/TestCases/strpbrk-1.c
index b7a784d99396..626e8777e1ef 100644
--- a/compiler-rt/test/asan/TestCases/strpbrk-1.c
+++ b/compiler-rt/test/asan/TestCases/strpbrk-1.c
@@ -6,14 +6,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   char *r;
   char s2[] = "ab";
-  char s1[] = {'c', 'a'};
-  char s3 = 0;
+  char s1[4] = "cab";
+  __asan_poison_memory_region ((char *)&s1[2], 2);
   r = strpbrk(s1, s2);
-  // CHECK:'s{{[1|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s1' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == s1 + 1);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strpbrk-2.c b/compiler-rt/test/asan/TestCases/strpbrk-2.c
index 748662be738b..29f3150e667f 100644
--- a/compiler-rt/test/asan/TestCases/strpbrk-2.c
+++ b/compiler-rt/test/asan/TestCases/strpbrk-2.c
@@ -6,14 +6,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   char *r;
   char s1[] = "c";
-  char s2[] = {'b', 'c'};
-  char s3 = 0;
+  char s2[4] = "bca";
+  __asan_poison_memory_region ((char *)&s2[2], 2);
   r = strpbrk(s1, s2);
-  // CHECK:'s{{[2|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s2' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == s1);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strspn-1.c b/compiler-rt/test/asan/TestCases/strspn-1.c
index c15869d90438..b0c40ea4d725 100644
--- a/compiler-rt/test/asan/TestCases/strspn-1.c
+++ b/compiler-rt/test/asan/TestCases/strspn-1.c
@@ -6,14 +6,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   size_t r;
   char s2[] = "ab";
-  char s1[] = {'a', 'c'};
-  char s3 = 0;
+  char s1[4] = "acb";
+  __asan_poison_memory_region ((char *)&s1[2], 2);
   r = strspn(s1, s2);
-  // CHECK:'s{{[1|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s1' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == 1);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strspn-2.c b/compiler-rt/test/asan/TestCases/strspn-2.c
index 57b3e6cd9473..4c899108de90 100644
--- a/compiler-rt/test/asan/TestCases/strspn-2.c
+++ b/compiler-rt/test/asan/TestCases/strspn-2.c
@@ -6,14 +6,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   size_t r;
   char s1[] = "bbc";
-  char s2[] = {'a', 'b'};
-  char s3 = 0;
+  char s2[5] = "abcd";
+  __asan_poison_memory_region ((char *)&s2[3], 2);
   r = strspn(s1, s2);
-  // CHECK:'s{{[2|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s2' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r >= 2);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strstr-1.c b/compiler-rt/test/asan/TestCases/strstr-1.c
index 842e1737e0ca..d0fa25bc62ba 100644
--- a/compiler-rt/test/asan/TestCases/strstr-1.c
+++ b/compiler-rt/test/asan/TestCases/strstr-1.c
@@ -7,14 +7,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   char *r = 0;
   char s2[] = "c";
-  char s1[] = {'a', 'c'};
-  char s3 = 0;
+  char s1[4] = "acb";
+  __asan_poison_memory_region ((char *)&s1[2], 2);
   r = strstr(s1, s2);
-  // CHECK:'s{{[1|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s1' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == s1 + 1);
   return 0;
 }
diff --git a/compiler-rt/test/asan/TestCases/strstr-2.c b/compiler-rt/test/asan/TestCases/strstr-2.c
index 77d7cc52a44b..edb700865b83 100644
--- a/compiler-rt/test/asan/TestCases/strstr-2.c
+++ b/compiler-rt/test/asan/TestCases/strstr-2.c
@@ -7,14 +7,15 @@
 
 #include <assert.h>
 #include <string.h>
+#include <sanitizer/asan_interface.h>
 
 int main(int argc, char **argv) {
   char *r = 0;
   char s1[] = "ab";
-  char s2[] = {'c'};
-  char s3 = 0;
+  char s2[4] = "cab";
+  __asan_poison_memory_region ((char *)&s2[2], 2);
   r = strstr(s1, s2);
-  // CHECK:'s{{[2|3]}}' <== Memory access at offset {{[0-9]+ .*}}flows this variable
+  // CHECK:'s2' <== Memory access at offset {{[0-9]+}} partially overflows this variable
   assert(r == 0);
   return 0;
 }