diff --git a/clang/lib/StaticAnalyzer/Core/MemRegion.cpp b/clang/lib/StaticAnalyzer/Core/MemRegion.cpp
--- a/clang/lib/StaticAnalyzer/Core/MemRegion.cpp
+++ b/clang/lib/StaticAnalyzer/Core/MemRegion.cpp
@@ -1077,13 +1077,16 @@
     }
   }
 
-  return getSubRegion<NonParamVarRegion>(D, sReg);
+  return getNonParamVarRegion(D, sReg);
 }
 
 const NonParamVarRegion *
 MemRegionManager::getNonParamVarRegion(const VarDecl *D,
                                        const MemRegion *superR) {
+  // Prefer the definition over the canonical decl as the canonical form.
   D = D->getCanonicalDecl();
+  if (const VarDecl *Def = D->getDefinition())
+    D = Def;
   return getSubRegion<NonParamVarRegion>(D, superR);
 }
 
diff --git a/clang/test/Analysis/globals.c b/clang/test/Analysis/globals.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Analysis/globals.c
@@ -0,0 +1,18 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,debug.ExprInspection -verify %s
+
+typedef typeof(sizeof(int)) size_t;
+size_t clang_analyzer_getExtent(const void *p);
+void clang_analyzer_dump(size_t n);
+
+extern const unsigned char extern_redecl[];
+const unsigned char extern_redecl[] = { 1,2,3,4 };
+const unsigned char tentative_redecl[];
+const unsigned char tentative_redecl[] = { 1,2,3,4 };
+
+const unsigned char direct_decl[] = { 1,2,3,4 };
+
+void test_redeclaration_extent(void) {
+  clang_analyzer_dump(clang_analyzer_getExtent(direct_decl));      // expected-warning {{4 S64b}}
+  clang_analyzer_dump(clang_analyzer_getExtent(extern_redecl));    // expected-warning {{4 S64b}}
+  clang_analyzer_dump(clang_analyzer_getExtent(tentative_redecl)); // expected-warning {{4 S64b}}
+}