Index: lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
+++ lib/StaticAnalyzer/Checkers/CStringSyntaxChecker.cpp
@@ -163,8 +163,7 @@
     uint64_t ILRawVal = IL->getValue().getZExtValue();
     if (const auto *Buffer = dyn_cast<ConstantArrayType>(DstArgDecl->getType())) {
       ASTContext &C = BR.getContext();
-      uint64_t Usize = C.getTypeSizeInChars(DstArg->getType()).getQuantity();
-      uint64_t BufferLen = BR.getContext().getTypeSize(Buffer) / Usize;
+      uint64_t BufferLen = C.getTypeSize(Buffer) / 8;
       if (BufferLen < ILRawVal)
         return true;
     }
Index: test/Analysis/cstring-syntax.c
===================================================================
--- test/Analysis/cstring-syntax.c
+++ test/Analysis/cstring-syntax.c
@@ -1,4 +1,7 @@
 // RUN: %clang_analyze_cc1 -analyzer-checker=unix.cstring.BadSizeArg -analyzer-store=region -Wno-strncat-size -Wno-strlcpy-strlcat-size -Wno-sizeof-array-argument -Wno-sizeof-pointer-memaccess -verify %s
+// RUN: %clang_analyze_cc1 -triple armv7-a15-linux -analyzer-checker=unix.cstring.BadSizeArg -analyzer-store=region -Wno-strncat-size -Wno-strlcpy-strlcat-size -Wno-sizeof-array-argument -Wno-sizeof-pointer-memaccess -verify %s
+// RUN: %clang_analyze_cc1 -triple aarch64_be-none-linux-gnu -analyzer-checker=unix.cstring.BadSizeArg -analyzer-store=region -Wno-strncat-size -Wno-strlcpy-strlcat-size -Wno-sizeof-array-argument -Wno-sizeof-pointer-memaccess -verify %s
+// RUN: %clang_analyze_cc1 -triple i386-apple-darwin10 -analyzer-checker=unix.cstring.BadSizeArg -analyzer-store=region -Wno-strncat-size -Wno-strlcpy-strlcat-size -Wno-sizeof-array-argument -Wno-sizeof-pointer-memaccess -verify %s
 
 typedef __SIZE_TYPE__ size_t;
 char  *strncat(char *, const char *, size_t);