diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -12920,6 +12920,9 @@
 }
 
 bool FixedPointExprEvaluator::VisitBinaryOperator(const BinaryOperator *E) {
+  if (E->isPtrMemOp() || E->isAssignmentOp() || E->getOpcode() == BO_Comma)
+    return ExprEvaluatorBaseTy::VisitBinaryOperator(E);
+
   const Expr *LHS = E->getLHS();
   const Expr *RHS = E->getRHS();
   FixedPointSemantics ResultFXSema =
diff --git a/clang/test/Frontend/fixed_point_crash.c b/clang/test/Frontend/fixed_point_crash.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Frontend/fixed_point_crash.c
@@ -0,0 +1,20 @@
+// RUN: %clang_cc1 -verify -ffixed-point %s
+
+union a {
+  _Accum x;
+  int i;
+};
+
+int fn1() {
+  union a m;
+  m.x = 5.6k;
+  return m.i;
+}
+
+int fn2() {
+  union a m;
+  m.x = 7, 5.6k; // expected-warning {{expression result unused}}
+  return m.x, m.i; // expected-warning {{expression result unused}}
+}
+
+_Accum acc = (0.5r, 6.9k); // expected-warning {{expression result unused}}