Index: lib/StaticAnalyzer/Core/RangedConstraintManager.cpp
===================================================================
--- lib/StaticAnalyzer/Core/RangedConstraintManager.cpp
+++ lib/StaticAnalyzer/Core/RangedConstraintManager.cpp
@@ -52,17 +52,18 @@
     assert(BinaryOperator::isComparisonOp(Op));
 
     // For now, we only support comparing pointers.
-    assert(Loc::isLocType(SSE->getLHS()->getType()));
-    assert(Loc::isLocType(SSE->getRHS()->getType()));
-    QualType DiffTy = SymMgr.getContext().getPointerDiffType();
-    SymbolRef Subtraction =
-        SymMgr.getSymSymExpr(SSE->getRHS(), BO_Sub, SSE->getLHS(), DiffTy);
-
-    const llvm::APSInt &Zero = getBasicVals().getValue(0, DiffTy);
-    Op = BinaryOperator::reverseComparisonOp(Op);
-    if (!Assumption)
-      Op = BinaryOperator::negateComparisonOp(Op);
-    return assumeSymRel(State, Subtraction, Op, Zero);
+    if (Loc::isLocType(SSE->getLHS()->getType()) &&
+        Loc::isLocType(SSE->getRHS()->getType())) {
+      QualType DiffTy = SymMgr.getContext().getPointerDiffType();
+      SymbolRef Subtraction =
+          SymMgr.getSymSymExpr(SSE->getRHS(), BO_Sub, SSE->getLHS(), DiffTy);
+
+      const llvm::APSInt &Zero = getBasicVals().getValue(0, DiffTy);
+      Op = BinaryOperator::reverseComparisonOp(Op);
+      if (!Assumption)
+        Op = BinaryOperator::negateComparisonOp(Op);
+      return assumeSymRel(State, Subtraction, Op, Zero);
+    }
   }
 
   // If we get here, there's nothing else we can do but treat the symbol as
Index: lib/StaticAnalyzer/Core/SValBuilder.cpp
===================================================================
--- lib/StaticAnalyzer/Core/SValBuilder.cpp
+++ lib/StaticAnalyzer/Core/SValBuilder.cpp
@@ -377,11 +377,9 @@
                                    BinaryOperator::Opcode Op,
                                    NonLoc LHS, NonLoc RHS,
                                    QualType ResultTy) {
-  if (!State->isTainted(RHS) && !State->isTainted(LHS))
-    return UnknownVal();
-
   const SymExpr *symLHS = LHS.getAsSymExpr();
   const SymExpr *symRHS = RHS.getAsSymExpr();
+
   // TODO: When the Max Complexity is reached, we should conjure a symbol
   // instead of generating an Unknown value and propagate the taint info to it.
   const unsigned MaxComp = 10000; // 100000 28X
Index: test/Analysis/PR37855.c
===================================================================
--- test/Analysis/PR37855.c
+++ test/Analysis/PR37855.c
@@ -20,5 +20,5 @@
     nodep = n;
   }
   if (nodep) // expected-warning {{Branch condition evaluates to a garbage value}}
-    n[1].node->s; // expected-warning {{Dereference of undefined pointer value}}
+    n[1].node->s;
 }
Index: test/Analysis/bitwise-ops.c
===================================================================
--- test/Analysis/bitwise-ops.c
+++ test/Analysis/bitwise-ops.c
@@ -9,8 +9,8 @@
   CHECK(x & 1); // expected-warning{{TRUE}}
   
   // False positives due to SValBuilder giving up on certain kinds of exprs.
-  CHECK(1 - x); // expected-warning{{UNKNOWN}}
-  CHECK(x & y); // expected-warning{{UNKNOWN}}
+  CHECK(1 - x); // expected-warning{{TRUE}}
+  CHECK(x & y); // expected-warning{{TRUE}}
 }
 
 int testConstantShifts_PR18073(int which) {
Index: test/Analysis/std-c-library-functions.c
===================================================================
--- test/Analysis/std-c-library-functions.c
+++ test/Analysis/std-c-library-functions.c
@@ -57,8 +57,7 @@
   size_t y = fread(buf, sizeof(int), 10, fp);
   clang_analyzer_eval(y <= 10); // expected-warning{{TRUE}}
   size_t z = fwrite(buf, sizeof(int), y, fp);
-  // FIXME: should be TRUE once symbol-symbol constraint support is improved.
-  clang_analyzer_eval(z <= y); // expected-warning{{UNKNOWN}}
+  clang_analyzer_eval(z <= y); // expected-warning{{TRUE}}
 }
 
 ssize_t getline(char **, size_t *, FILE *);
Index: test/Analysis/svalbuilder-rearrange-comparisons.c
===================================================================
--- test/Analysis/svalbuilder-rearrange-comparisons.c
+++ test/Analysis/svalbuilder-rearrange-comparisons.c
@@ -560,7 +560,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(y); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(x == y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) + 1U) == (conj_$2{int})}}
 }
 
 void compare_same_symbol_minus_left_int_equal_unsigned() {
@@ -569,7 +570,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(y); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(x == y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) - 1U) == (conj_$2{int})}}
 }
 
 void compare_same_symbol_plus_right_int_equal_unsigned() {
@@ -577,7 +579,8 @@
   clang_analyzer_dump(x); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(x == y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{(conj_$2{int}) == ((conj_$2{int}) + 1U)}}
 }
 
 void compare_same_symbol_minus_right_int_equal_unsigned() {
@@ -585,7 +588,8 @@
   clang_analyzer_dump(x); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(x == y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{(conj_$2{int}) == ((conj_$2{int}) - 1U)}}
 }
 
 void compare_same_symbol_plus_left_plus_right_int_equal_unsigned() {
@@ -603,7 +607,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(x == y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) + 1U) == ((conj_$2{int}) - 1U)}}
 }
 
 void compare_same_symbol_minus_left_plus_right_int_equal_unsigned() {
@@ -612,7 +617,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(x == y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) - 1U) == ((conj_$2{int}) + 1U)}}
 }
 
 void compare_same_symbol_minus_left_minus_right_int_equal_unsigned() {
@@ -710,7 +716,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(y); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(x <= y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) + 1U) <= (conj_$2{int})}}
 }
 
 void compare_same_symbol_minus_left_int_less_or_equal_unsigned() {
@@ -719,7 +726,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(y); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(x <= y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) - 1U) <= (conj_$2{int})}}
 }
 
 void compare_same_symbol_plus_right_int_less_or_equal_unsigned() {
@@ -727,7 +735,8 @@
   clang_analyzer_dump(x); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(x <= y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{(conj_$2{int}) <= ((conj_$2{int}) + 1U)}}
 }
 
 void compare_same_symbol_minus_right_int_less_or_equal_unsigned() {
@@ -735,7 +744,8 @@
   clang_analyzer_dump(x); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(x <= y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{(conj_$2{int}) <= ((conj_$2{int}) - 1U)}}
 }
 
 void compare_same_symbol_plus_left_plus_right_int_less_or_equal_unsigned() {
@@ -753,7 +763,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(x <= y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) + 1U) <= ((conj_$2{int}) - 1U)}}
 }
 
 void compare_same_symbol_minus_left_plus_right_int_less_or_equal_unsigned() {
@@ -762,7 +773,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(x <= y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) - 1U) <= ((conj_$2{int}) + 1U)}}
 }
 
 void compare_same_symbol_minus_left_minus_right_int_less_or_equal_unsigned() {
@@ -860,7 +872,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(y); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(x < y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) + 1U) < (conj_$2{int})}}
 }
 
 void compare_same_symbol_minus_left_int_less_unsigned() {
@@ -869,7 +882,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(y); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(x < y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) - 1U) < (conj_$2{int})}}
 }
 
 void compare_same_symbol_plus_right_int_less_unsigned() {
@@ -877,7 +891,8 @@
   clang_analyzer_dump(x); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(x < y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{(conj_$2{int}) < ((conj_$2{int}) + 1U)}}
 }
 
 void compare_same_symbol_minus_right_int_less_unsigned() {
@@ -885,7 +900,8 @@
   clang_analyzer_dump(x); // expected-warning{{conj_$2{int}}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(x < y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{(conj_$2{int}) < ((conj_$2{int}) - 1U)}}
 }
 
 void compare_same_symbol_plus_left_plus_right_int_less_unsigned() {
@@ -903,7 +919,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(x < y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) + 1U) < ((conj_$2{int}) - 1U)}}
 }
 
 void compare_same_symbol_minus_left_plus_right_int_less_unsigned() {
@@ -912,7 +929,8 @@
   clang_analyzer_dump(x); // expected-warning{{(conj_$2{int}) - 1}}
   clang_analyzer_dump(y); // expected-warning{{(conj_$2{int}) + 1}}
   clang_analyzer_dump(x < y);
-  // expected-warning@-1{{Unknown}} // FIXME: Can this be simplified?
+  // FIXME: Can this be simplified?
+  // expected-warning@-2{{((conj_$2{int}) - 1U) < ((conj_$2{int}) + 1U)}}
 }
 
 void compare_same_symbol_minus_left_minus_right_int_less_unsigned() {