Index: clang/include/clang/StaticAnalyzer/Checkers/SValExplainer.h
===================================================================
--- clang/include/clang/StaticAnalyzer/Checkers/SValExplainer.h
+++ clang/include/clang/StaticAnalyzer/Checkers/SValExplainer.h
@@ -103,7 +103,10 @@
   }
 
   std::string VisitSymbolDerived(const SymbolDerived *S) {
-    return "value derived from (" + Visit(S->getParentSymbol()) +
+    std::string Prefix = "";
+    if (const auto *SRV = dyn_cast<SymbolRegionValue>(S->getParentSymbol()))
+      Prefix = "initial ";
+    return Prefix + "value derived from (" + Visit(S->getParentSymbol()) +
            ") for " + Visit(S->getRegion());
   }
 
Index: clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
+++ clang/lib/StaticAnalyzer/Core/ExprEngine.cpp
@@ -304,6 +304,16 @@
     }
   }
 
+  if (const auto *FD = dyn_cast<FunctionDecl>(D)) {
+    // Fill the Store with initial value of parameters.
+    for (const ParmVarDecl *PVD : FD->parameters()) {
+      const auto *TVR =
+          state->getRegion(PVD, InitLoc)->castAs<TypedValueRegion>();
+      state = state->bindLoc(loc::MemRegionVal(TVR),
+                             svalBuilder.getRegionValueSymbolVal(TVR), InitLoc);
+    }
+  }
+
   return state;
 }
 
Index: clang/test/Analysis/explain-svals.c
===================================================================
--- clang/test/Analysis/explain-svals.c
+++ clang/test/Analysis/explain-svals.c
@@ -25,5 +25,5 @@
 void test_2(struct S s) {
   clang_analyzer_explain_S(s);      //expected-warning-re{{{{^lazily frozen compound value of parameter 's'$}}}}
   clang_analyzer_explain_voidp(&s); // expected-warning-re{{{{^pointer to parameter 's'$}}}}
-  clang_analyzer_explain_int(s.z);  // expected-warning-re{{{{^initial value of field 'z' of parameter 's'$}}}}
+  clang_analyzer_explain_int(s.z);  // expected-warning-re{{{{^initial value derived from \(argument 's'\) for field 'z' of parameter 's'$}}}}
 }
Index: clang/test/Analysis/explain-svals.cpp
===================================================================
--- clang/test/Analysis/explain-svals.cpp
+++ clang/test/Analysis/explain-svals.cpp
@@ -59,7 +59,7 @@
 
 void test_3(S s) {
   clang_analyzer_explain(&s); // expected-warning-re{{{{^pointer to parameter 's'$}}}}
-  clang_analyzer_explain(s.z); // expected-warning-re{{{{^initial value of field 'z' of parameter 's'$}}}}
+  clang_analyzer_explain(s.z); // expected-warning-re{{{{^initial value derived from \(argument 's'\) for field 'z' of parameter 's'$}}}}
   clang_analyzer_explain(&s.s2[5].y[3]); // expected-warning-re{{{{^pointer to element of type 'int' with index 3 of field 'y' of base object 'S::S3' inside element of type 'struct S::S2' with index 5 of field 's2' of parameter 's'$}}}}
   if (!s.s2[7].x) {
     clang_analyzer_explain(s.s2[7].x); // expected-warning-re{{{{^concrete memory address '0'$}}}}
Index: clang/test/Analysis/expr-inspection.c
===================================================================
--- clang/test/Analysis/expr-inspection.c
+++ clang/test/Analysis/expr-inspection.c
@@ -28,6 +28,9 @@
 // CHECK-NEXT:   "store": { "pointer": "{{0x[0-9a-f]+}}", "items": [
 // CHECK-NEXT:     { "cluster": "y", "pointer": "{{0x[0-9a-f]+}}", "items": [
 // CHECK-NEXT:       { "kind": "Direct", "offset": 0, "value": "2 S32b" }
+// CHECK-NEXT:     ]},
+// CHECK-NEXT:     { "cluster": "x", "pointer": "{{0x[0-9a-f]+}}", "items": [
+// CHECK-NEXT:       { "kind": "Direct", "offset": 0, "value": "reg_$0<int x>" }
 // CHECK-NEXT:     ]}
 // CHECK-NEXT:   ]},
 // CHECK-NEXT:   "environment": { "pointer": "{{0x[0-9a-f]+}}", "items": [
Index: clang/test/Analysis/osobject-retain-release.cpp
===================================================================
--- clang/test/Analysis/osobject-retain-release.cpp
+++ clang/test/Analysis/osobject-retain-release.cpp
@@ -35,7 +35,7 @@
 
   static OSArray* consumeArrayHasCode(OS_CONSUME OSArray * array) { // expected-note{{Parameter 'array' starts at +1, as it is marked as consuming}}
     return nullptr; // expected-warning{{Potential leak of an object of type 'OSArray'}}
-// expected-note@-1{{Object leaked: allocated object of type 'OSArray' is not referenced later in this execution path and has a retain count of +1}}
+// expected-note@-1{{Object leaked: object allocated and stored into 'array' is not referenced later in this execution path and has a retain count of +1}}
   }
 
 
@@ -70,7 +70,7 @@
   a->release();
   b->retain(); // expected-note{{Reference count incremented. The object now has a +1 retain count}}
 } // expected-warning{{Potential leak of an object of type 'OSObject'}}
-// expected-note@-1{{Object leaked: allocated object of type 'OSObject' is not referenced later in this execution path and has a retain count of +1}}
+// expected-note@-1{{Object leaked: object allocated and stored into 'b' is not referenced later in this execution path and has a retain count of +1}}
 
 void escape(void *);
 void escape_with_source(void *p) {}