diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
index 1ca040fd7e4..37b54bb528b 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2CPPTests.java
@@ -256,7 +256,7 @@ public class AST2CPPTests extends AST2TestBase {
 		assertNotNull(second);
 		assertTrue("Expected types to be the same, but first was: '" + first.toString() + "' and second was: '" + second + "'", first.isSameType(second));
 	}
-
+	
 	// int *zzz1 (char);
 	// int (*zzz2) (char);
 	// int ((*zzz3)) (char);
@@ -9062,6 +9062,13 @@ public class AST2CPPTests extends AST2TestBase {
 	public void testSizeofReference_397342() throws Exception {
 		parseAndCheckBindings();
 	}
+	
+	//	constexpr int waldo = sizeof("cat\b\\\n");
+	public void testSizeofStringLiteralWithEscapeCharacters_459279() throws Exception {
+		BindingAssertionHelper helper = getAssertionHelper();
+		ICPPVariable waldo = helper.assertNonProblem("waldo");
+		assertConstantValue(7, waldo);  // "cat" + backspace + slash + newline + null terminator
+	}
 
 	//	struct A {
 	//	  char a[100];
@@ -10666,7 +10673,7 @@ public class AST2CPPTests extends AST2TestBase {
 	public void testIsBaseOf_409100() throws Exception {
 		BindingAssertionHelper b = getAssertionHelper();
 		IVariable var = b.assertNonProblem("value");
-		assertEquals(1 /*true */, var.getInitialValue().numericalValue().longValue());
+		assertConstantValue(1 /*true */, var);
 	}
 
 	//  namespace NS {
@@ -10982,7 +10989,7 @@ public class AST2CPPTests extends AST2TestBase {
 	public void testConditionalExpressionFolding_429891() throws Exception {
 		BindingAssertionHelper helper = getAssertionHelper();
 		IVariable waldo = helper.assertNonProblem("waldo");
-		assertEquals(5, waldo.getInitialValue().numericalValue().longValue());
+		assertConstantValue(5, waldo);
 	}
 	
 	//	constexpr int naive_fibonacci(int x) {
@@ -11009,7 +11016,7 @@ public class AST2CPPTests extends AST2TestBase {
 	public void testNameLookupInDefaultArgument_432701() throws Exception {
 		BindingAssertionHelper helper = getAssertionHelper();
 		IVariable waldo = helper.assertNonProblem("waldo");
-		assertEquals(42, waldo.getInitialValue().numericalValue().longValue());
+		assertConstantValue(42, waldo);
 	}
 	
 	//	struct S1 { S1(int); };
diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
index 718be54a614..75a6432cfe8 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TemplateTests.java
@@ -3071,7 +3071,7 @@ public class AST2TemplateTests extends AST2TestBase {
 		ICPPVariable _256= ba.assertNonProblem("_256=0x100", 4, ICPPVariable.class);
 		IQualifierType qt1= assertInstance(_256.getType(), IQualifierType.class);
 		ICPPBasicType bt1= assertInstance(qt1.getType(), ICPPBasicType.class);
-		assertEquals(256, _256.getInitialValue().numericalValue().intValue());
+		assertConstantValue(256, _256);
 
 		ICPPVariable t= ba.assertNonProblem("t;", 1, ICPPVariable.class);
 		ICPPTemplateInstance ci1= assertInstance(t.getType(), ICPPTemplateInstance.class, ICPPClassType.class);
@@ -7390,9 +7390,7 @@ public class AST2TemplateTests extends AST2TestBase {
 	public void testSfinaeInNestedTypeInTemplateArgument_402257() throws Exception {
 		BindingAssertionHelper helper = new BindingAssertionHelper(getAboveComment(), true);
 		ICPPVariable B = helper.assertNonProblem("B");
-		Long val = B.getInitialValue().numericalValue();
-		assertNotNull(val);
-		assertEquals(0 /* false */, val.longValue());
+		assertConstantValue(0 /* false */, B);
 	}
 
 	//	struct S {
@@ -8038,9 +8036,7 @@ public class AST2TemplateTests extends AST2TestBase {
 	public void testSizeofParameterPackOnTypeid_401973() throws Exception {
 		BindingAssertionHelper helper = new BindingAssertionHelper(getAboveComment(), true);
 		ICPPVariable bar = helper.assertNonProblem("bar");
-		Long barValue = bar.getInitialValue().numericalValue();
-		assertNotNull(barValue);
-		assertEquals(2,  barValue.longValue());
+		assertConstantValue(2, bar);
 	}
 
 	//	template <int...> struct tuple_indices {};
@@ -8573,7 +8569,7 @@ public class AST2TemplateTests extends AST2TestBase {
 	public void testSpecializationOfConstexprFunction_420995() throws Exception {
 		BindingAssertionHelper helper = getAssertionHelper();
 		ICPPVariable waldo = helper.assertNonProblem("waldo");
-		assertEquals(2, waldo.getInitialValue().numericalValue().longValue());
+		assertConstantValue(2, waldo);
 	}
 	
 	//	struct Test {
diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TestBase.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TestBase.java
index 13fdbffc576..40794207cd5 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TestBase.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/core/parser/tests/ast2/AST2TestBase.java
@@ -60,6 +60,7 @@ import org.eclipse.cdt.core.dom.ast.IField;
 import org.eclipse.cdt.core.dom.ast.IFunctionType;
 import org.eclipse.cdt.core.dom.ast.IProblemBinding;
 import org.eclipse.cdt.core.dom.ast.IType;
+import org.eclipse.cdt.core.dom.ast.IValue;
 import org.eclipse.cdt.core.dom.ast.IVariable;
 import org.eclipse.cdt.core.dom.ast.c.ICASTTypeIdInitializerExpression;
 import org.eclipse.cdt.core.dom.ast.cpp.ICPPASTLinkageSpecification;
@@ -494,6 +495,14 @@ public class AST2TestBase extends BaseTestCase {
     	assertEquals(ownerName, struct.getName());
     }
 
+	protected static void assertConstantValue(long expected, IVariable constant) {
+		IValue value = constant.getInitialValue();
+		assertNotNull(value);
+		Long numericalValue = value.numericalValue();
+		assertNotNull(numericalValue);
+		assertEquals(expected, numericalValue.longValue());
+	}
+
 	protected class BindingAssertionHelper {
 		protected IASTTranslationUnit tu;
 		protected String contents;
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTLiteralExpression.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTLiteralExpression.java
index 9a9391c2ff9..c97b28a75a7 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTLiteralExpression.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/dom/parser/cpp/CPPASTLiteralExpression.java
@@ -42,6 +42,7 @@ public class CPPASTLiteralExpression extends ASTNode implements ICPPASTLiteralEx
 	
     private int kind;
     private char[] value = CharArrayUtils.EMPTY;
+    private int fStringLiteralSize = -1;  // accounting for escape sequences and the null terminator
 	private ICPPEvaluation fEvaluation;
 
     public CPPASTLiteralExpression() {
@@ -110,31 +111,73 @@ public class CPPASTLiteralExpression extends ASTNode implements ICPPASTLiteralEx
         return true;
     }
     
-	private IValue getStringLiteralSize() {
-		char[] value= getValue();
-		int length= value.length-1;
-		boolean isRaw= false;
-		for (int i = 0; i < length; i++) {
-			final char c = value[i];
-			if (c == '"') {
-				if (isRaw) {
-					for (int j = i + 1; j < length; j++) {
-						final char d= value[j];
-						if (d == '(') {
-							length -= 2*(j-i);
-							break;
-						}
-					}
-				}
-				length -= i;
-				if (length < 0)
-					length = 0;
-				break;
-			} else if (c == 'R') {
-				isRaw = true;
+    private int computeStringLiteralSize() {
+    	int start = 0, end = value.length - 1;
+    	boolean isRaw = false;
+    	
+    	// Skip past a prefix affecting the character type.
+    	if (value[0] == 'L' || value[0] == 'u' || value[0] == 'U') {
+    		++start;
+    	}
+    	
+    	// If there is an 'R' prefix, skip past it but take note of it.
+    	if (value[start] == 'R') {
+    		++start;
+    		isRaw = true;
+    	}
+    	
+    	// Now we should have a quote-enclosed string. Skip past the quotes.
+    	if (!(value[start] == '"' && value[end] == '"')) {
+    		// Unexpected!
+    		return 0;
+    	}
+    	++start;
+    	--end;
+    	
+    	// If we have a raw string, skip past the raw prefix.
+    	if (isRaw) {
+    		while (value[start] != '(' && start <= end) {
+    			++start;
+    			--end;
+    		}
+    		
+    		// Now we should have a parenthesis-enclosed string.
+    		if (!(value[start] == '(' && value[end] == ')')) {
+    			// Unexpected!
+    			return 0;
+    		}
+    		
+    		// Since the string is raw, we don't need to process
+    		// escape sequences, so the size is just the number
+    		// of remaining characters, plus 1 for the null terminator.
+    		return (end - start + 1) + 1;
+    	}
+    	
+    	// Otherwise, we have a non-raw string and we need to
+    	// process escape sequences.
+    	int length = 0;
+    	boolean escaping = false;
+    	for (; start <= end; ++start) {
+    		if (escaping) {
+    			escaping = false;
+    			++length;
+    		} else if (value[start] == '\\') {
+				escaping = true;
+			} else {
+				++length;
 			}
+    		// TODO: Handle fancier things like octal literals.
+    	}
+    	
+    	// + 1 for null terminator.
+    	return length + 1;
+    }
+    
+	private IValue getStringLiteralSize() {
+		if (fStringLiteralSize == -1) {
+			fStringLiteralSize = computeStringLiteralSize();
 		}
-		return Value.create(length);
+		return Value.create(fStringLiteralSize);
 	}
 
 	private Kind getCharType() {