diff --git a/source/opt/scalar_replacement_pass.h b/source/opt/scalar_replacement_pass.h
index 7fb8915fb..3d1377bf7 100644
--- a/source/opt/scalar_replacement_pass.h
+++ b/source/opt/scalar_replacement_pass.h
@@ -15,6 +15,7 @@
 #ifndef SOURCE_OPT_SCALAR_REPLACEMENT_PASS_H_
 #define SOURCE_OPT_SCALAR_REPLACEMENT_PASS_H_
 
+#include <cassert>
 #include <cstdio>
 #include <memory>
 #include <queue>
@@ -37,11 +38,10 @@ class ScalarReplacementPass : public MemPass {
  public:
   ScalarReplacementPass(uint32_t limit = kDefaultLimit)
       : max_num_elements_(limit) {
-    name_[0] = '\0';
-    strcat(name_, "scalar-replacement=");
-    const size_t name_len = strlen(name_);
-    snprintf(&name_[name_len], sizeof(name_) - name_len, "%d",
-             max_num_elements_);
+    const auto num_to_write = snprintf(
+        name_, sizeof(name_), "scalar-replacement=%u", max_num_elements_);
+    assert(size_t(num_to_write) < sizeof(name_));
+    (void)num_to_write;  // Mark as unused
   }
 
   const char* name() const override { return name_; }
@@ -255,7 +255,10 @@ class ScalarReplacementPass : public MemPass {
   // Limit on the number of members in an object that will be replaced.
   // 0 means there is no limit.
   uint32_t max_num_elements_;
-  char name_[55];
+  // This has to be big enough to fit "scalar-replacement=" followed by a
+  // uint32_t number written in decimal (so 10 digits), and then a
+  // terminating nul.
+  char name_[30];
 };
 
 }  // namespace opt
diff --git a/test/opt/scalar_replacement_test.cpp b/test/opt/scalar_replacement_test.cpp
index 7db997d4a..0c97c80b7 100644
--- a/test/opt/scalar_replacement_test.cpp
+++ b/test/opt/scalar_replacement_test.cpp
@@ -12,6 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "source/opt/scalar_replacement_pass.h"
+
 #include <string>
 
 #include "gmock/gmock.h"
@@ -23,6 +25,18 @@ namespace spvtools {
 namespace opt {
 namespace {
 
+using ScalarReplacementPassName = ::testing::Test;
+
+TEST_F(ScalarReplacementPassName, Default) {
+  auto srp = ScalarReplacementPass();
+  EXPECT_STREQ(srp.name(), "scalar-replacement=100");
+}
+
+TEST_F(ScalarReplacementPassName, Large) {
+  auto srp = ScalarReplacementPass(0xffffffffu);
+  EXPECT_STREQ(srp.name(), "scalar-replacement=4294967295");
+}
+
 using ScalarReplacementTest = PassTest<::testing::Test>;
 
 TEST_F(ScalarReplacementTest, SimpleStruct) {