PR jit/66539: Add parentheses as needed to gcc_jit_object_get_debug_string

gcc/jit/ChangeLog:
	PR jit/66539
	* jit-recording.c: Within namespace gcc::jit::recording::
	(rvalue::get_debug_string_parens): New function.
	(binary_op::make_debug_string): Update to mimic C precedence
	rules.
	(binary_op_precedence): New array.
	(binary_op::get_precedence): New function.
	(comparison::make_debug_string): Update to mimic C precedence
	rules.
	(comparison_precedence): New array.
	(comparison::get_precedence): New function.
	(cast::make_debug_string): Update to mimic C precedence rules.
	(call::make_debug_string): Likewise.
	(call_through_ptr::make_debug_string): Likewise.
	(array_access::make_debug_string): Likewise.
	(access_field_of_lvalue::make_debug_string): Likewise.
	(access_field_rvalue::make_debug_string): Likewise.
	(dereference_field_rvalue::make_debug_string): Likewise.
	(dereference_rvalue::make_debug_string): Likewise.
	(get_address_of_lvalue::make_debug_string): Likewise.
	* jit-recording.h: Within namespace gcc::jit::recording::
	(precedence): New enum.
	(rvalue::rvalue): Initialize field "m_parenthesized_string".
	(rvalue::get_debug_string_parens): New method.
	(rvalue::get_precedence): New pure virtual function.
	(rvalue::m_parenthesized_string): New field.
	(param::get_precedence): New function.
	(global::get_precedence): New function.
	(memento_of_new_rvalue_from_const::get_precedence): New function.
	(memento_of_new_string_literal::get_precedence): New function.
	(unary_op::get_precedence): New function.
	(binary_op::get_precedence): New function.
	(comparison::get_precedence): New function.
	(cast::get_precedence): New function.
	(call::get_precedence): New function.
	(call_through_ptr::get_precedence): New function.
	(array_access::get_precedence): New function.
	(access_field_of_lvalue::get_precedence): New function.
	(access_field_rvalue::get_precedence): New function.
	(dereference_field_rvalue::get_precedence): New function.
	(dereference_rvalue::get_precedence): New function.
	(get_address_of_lvalue::get_precedence): New function.
	(local::get_precedence): New function.

gcc/testsuite/ChangeLog:
	PR jit/66539
	* jit.dg/all-non-failing-tests.h: Add test-debug-strings.c.
	* jit.dg/test-debug-strings.c: New test case.
	* jit.dg/test-quadratic.c (make_calc_discriminant): Verify that
	the discriminant has a sane debug string.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@224531 138bc75d-0d04-0410-961f-82ee72b054a4

7 files changed, 447 insertions, 31 deletions

diff --git a/gcc/jit/ChangeLog b/gcc/jit/ChangeLog
index 0d00f3bcdbf..0ba2fd6cc87 100644
--- a/gcc/jit/ChangeLog
+++ b/gcc/jit/ChangeLog
@@ -1,3 +1,49 @@
+2015-06-16  David Malcolm  <dmalcolm@redhat.com>
+
+	PR jit/66539
+	* jit-recording.c: Within namespace gcc::jit::recording::
+	(rvalue::get_debug_string_parens): New function.
+	(binary_op::make_debug_string): Update to mimic C precedence
+	rules.
+	(binary_op_precedence): New array.
+	(binary_op::get_precedence): New function.
+	(comparison::make_debug_string): Update to mimic C precedence
+	rules.
+	(comparison_precedence): New array.
+	(comparison::get_precedence): New function.
+	(cast::make_debug_string): Update to mimic C precedence rules.
+	(call::make_debug_string): Likewise.
+	(call_through_ptr::make_debug_string): Likewise.
+	(array_access::make_debug_string): Likewise.
+	(access_field_of_lvalue::make_debug_string): Likewise.
+	(access_field_rvalue::make_debug_string): Likewise.
+	(dereference_field_rvalue::make_debug_string): Likewise.
+	(dereference_rvalue::make_debug_string): Likewise.
+	(get_address_of_lvalue::make_debug_string): Likewise.
+	* jit-recording.h: Within namespace gcc::jit::recording::
+	(precedence): New enum.
+	(rvalue::rvalue): Initialize field "m_parenthesized_string".
+	(rvalue::get_debug_string_parens): New method.
+	(rvalue::get_precedence): New pure virtual function.
+	(rvalue::m_parenthesized_string): New field.
+	(param::get_precedence): New function.
+	(global::get_precedence): New function.
+	(memento_of_new_rvalue_from_const::get_precedence): New function.
+	(memento_of_new_string_literal::get_precedence): New function.
+	(unary_op::get_precedence): New function.
+	(binary_op::get_precedence): New function.
+	(comparison::get_precedence): New function.
+	(cast::get_precedence): New function.
+	(call::get_precedence): New function.
+	(call_through_ptr::get_precedence): New function.
+	(array_access::get_precedence): New function.
+	(access_field_of_lvalue::get_precedence): New function.
+	(access_field_rvalue::get_precedence): New function.
+	(dereference_field_rvalue::get_precedence): New function.
+	(dereference_rvalue::get_precedence): New function.
+	(get_address_of_lvalue::get_precedence): New function.
+	(local::get_precedence): New function.
+
 2015-06-09  Matthias Klose  <doko@ubuntu.com>
 
 	* Make-lang.in (jit.install-common): Install headers using INSTALL_DATA.
diff --git a/gcc/jit/jit-recording.c b/gcc/jit/jit-recording.c
index 32d7f31a8c3..f379b58ec81 100644
--- a/gcc/jit/jit-recording.c
+++ b/gcc/jit/jit-recording.c
@@ -3021,6 +3021,63 @@ recording::rvalue::access_as_rvalue (reproducer &r)
   return r.get_identifier (this);
 }
 
+/* Return a debug string for the given rvalue, wrapping it in parentheses
+   if needed to mimic C's precedence rules, i.e. if OUTER_PREC is of
+   stronger precedence that this rvalue's precedence.
+
+   For example, given:
+
+           MULT
+          /    \
+       PLUS     MINUS
+      /    \   /     \
+     A      B C       D
+
+   we want to emit:
+
+     (A + B) * (C - D)
+
+   since MULT has strong precedence than PLUS and MINUS, whereas for:
+
+           PLUS
+          /    \
+       MULT     DIVIDE
+      /    \   /      \
+     A      B C        D
+
+   we can simply emit:
+
+     A * B + C / D
+
+   since PLUS has weaker precedence than MULT and DIVIDE.  */
+
+const char *
+recording::rvalue::get_debug_string_parens (enum precedence outer_prec)
+{
+  enum precedence this_prec = get_precedence ();
+
+  /* If this_prec has stronger precedence than outer_prec, we don't
+     need to wrap this in parens within the outer debug string.
+     Stronger precedences occur earlier than weaker within the enum,
+     so this is a less than test.  Equal precedences don't need
+     parentheses.  */
+  if (this_prec <= outer_prec)
+    return get_debug_string();
+
+  /* Otherwise, we need parentheses.  */
+
+  /* Lazily-build and cache m_parenthesized_string.  */
+  if (!m_parenthesized_string)
+    {
+      const char *debug_string = get_debug_string ();
+      m_parenthesized_string = string::from_printf (get_context (),
+						    "(%s)",
+						    debug_string);
+    }
+  gcc_assert (m_parenthesized_string);
+  return m_parenthesized_string->c_str ();
+}
+
 
 /* The implementation of class gcc::jit::recording::lvalue.  */
 
@@ -4251,11 +4308,12 @@ static const char * const binary_op_strings[] = {
 recording::string *
 recording::binary_op::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "%s %s %s",
-			      m_a->get_debug_string (),
+			      m_a->get_debug_string_parens (prec),
 			      binary_op_strings[m_op],
-			      m_b->get_debug_string ());
+			      m_b->get_debug_string_parens (prec));
 }
 
 static const char * const binary_op_reproducer_strings[] = {
@@ -4295,6 +4353,31 @@ recording::binary_op::write_reproducer (reproducer &r)
 	   r.get_identifier_as_rvalue (m_b));
 }
 
+namespace recording {
+static const enum precedence binary_op_precedence[] = {
+  PRECEDENCE_ADDITIVE, /* GCC_JIT_BINARY_OP_PLUS */
+  PRECEDENCE_ADDITIVE, /* GCC_JIT_BINARY_OP_MINUS */
+
+  PRECEDENCE_MULTIPLICATIVE, /* GCC_JIT_BINARY_OP_MULT */
+  PRECEDENCE_MULTIPLICATIVE, /* GCC_JIT_BINARY_OP_DIVIDE */
+  PRECEDENCE_MULTIPLICATIVE, /* GCC_JIT_BINARY_OP_MODULO */
+
+  PRECEDENCE_BITWISE_AND, /* GCC_JIT_BINARY_OP_BITWISE_AND */
+  PRECEDENCE_BITWISE_XOR, /* GCC_JIT_BINARY_OP_BITWISE_XOR */
+  PRECEDENCE_BITWISE_IOR, /* GCC_JIT_BINARY_OP_BITWISE_OR */
+  PRECEDENCE_LOGICAL_AND, /* GCC_JIT_BINARY_OP_LOGICAL_AND */
+  PRECEDENCE_LOGICAL_OR, /* GCC_JIT_BINARY_OP_LOGICAL_OR */
+  PRECEDENCE_SHIFT, /* GCC_JIT_BINARY_OP_LSHIFT */
+  PRECEDENCE_SHIFT, /* GCC_JIT_BINARY_OP_RSHIFT */
+};
+} /* namespace recording */
+
+enum recording::precedence
+recording::binary_op::get_precedence () const
+{
+  return binary_op_precedence[m_op];
+}
+
 /* The implementation of class gcc::jit::recording::comparison.  */
 
 /* Implementation of recording::memento::make_debug_string for
@@ -4313,11 +4396,12 @@ static const char * const comparison_strings[] =
 recording::string *
 recording::comparison::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "%s %s %s",
-			      m_a->get_debug_string (),
+			      m_a->get_debug_string_parens (prec),
 			      comparison_strings[m_op],
-			      m_b->get_debug_string ());
+			      m_b->get_debug_string_parens (prec));
 }
 
 /* A table of enum gcc_jit_comparison values expressed in string
@@ -4375,6 +4459,25 @@ recording::comparison::visit_children (rvalue_visitor *v)
   v->visit (m_b);
 }
 
+namespace recording {
+static const enum precedence comparison_precedence[] =
+{
+  PRECEDENCE_EQUALITY, /* GCC_JIT_COMPARISON_EQ */
+  PRECEDENCE_EQUALITY, /* GCC_JIT_COMPARISON_NE */
+
+  PRECEDENCE_RELATIONAL,  /* GCC_JIT_COMPARISON_LT */
+  PRECEDENCE_RELATIONAL, /* GCC_JIT_COMPARISON_LE */
+  PRECEDENCE_RELATIONAL,  /* GCC_JIT_COMPARISON_GT */
+  PRECEDENCE_RELATIONAL, /* GCC_JIT_COMPARISON_GE */
+};
+} /* namespace recording */
+
+enum recording::precedence
+recording::comparison::get_precedence () const
+{
+  return comparison_precedence[m_op];
+}
+
 /* Implementation of pure virtual hook recording::memento::replay_into
    for recording::cast.  */
 
@@ -4400,10 +4503,11 @@ recording::cast::visit_children (rvalue_visitor *v)
 recording::string *
 recording::cast::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "(%s)%s",
 			      get_type ()->get_debug_string (),
-			      m_rvalue->get_debug_string ());
+			      m_rvalue->get_debug_string_parens (prec));
 }
 
 /* Implementation of recording::memento::write_reproducer for casts.  */
@@ -4473,12 +4577,13 @@ recording::call::visit_children (rvalue_visitor *v)
 recording::string *
 recording::call::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   /* First, build a buffer for the arguments.  */
   /* Calculate length of said buffer.  */
   size_t sz = 1; /* nil terminator */
   for (unsigned i = 0; i< m_args.length (); i++)
     {
-      sz += strlen (m_args[i]->get_debug_string ());
+      sz += strlen (m_args[i]->get_debug_string_parens (prec));
       sz += 2; /* ", " separator */
     }
 
@@ -4488,8 +4593,8 @@ recording::call::make_debug_string ()
 
   for (unsigned i = 0; i< m_args.length (); i++)
     {
-      strcpy (argbuf + len, m_args[i]->get_debug_string ());
-      len += strlen (m_args[i]->get_debug_string ());
+      strcpy (argbuf + len, m_args[i]->get_debug_string_parens (prec));
+      len += strlen (m_args[i]->get_debug_string_parens (prec));
       if (i + 1 < m_args.length ())
 	{
 	  strcpy (argbuf + len, ", ");
@@ -4586,12 +4691,13 @@ recording::call_through_ptr::visit_children (rvalue_visitor *v)
 recording::string *
 recording::call_through_ptr::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   /* First, build a buffer for the arguments.  */
   /* Calculate length of said buffer.  */
   size_t sz = 1; /* nil terminator */
   for (unsigned i = 0; i< m_args.length (); i++)
     {
-      sz += strlen (m_args[i]->get_debug_string ());
+      sz += strlen (m_args[i]->get_debug_string_parens (prec));
       sz += 2; /* ", " separator */
     }
 
@@ -4601,8 +4707,8 @@ recording::call_through_ptr::make_debug_string ()
 
   for (unsigned i = 0; i< m_args.length (); i++)
     {
-      strcpy (argbuf + len, m_args[i]->get_debug_string ());
-      len += strlen (m_args[i]->get_debug_string ());
+      strcpy (argbuf + len, m_args[i]->get_debug_string_parens (prec));
+      len += strlen (m_args[i]->get_debug_string_parens (prec));
       if (i + 1 < m_args.length ())
 	{
 	  strcpy (argbuf + len, ", ");
@@ -4614,7 +4720,7 @@ recording::call_through_ptr::make_debug_string ()
   /* ...and use it to get the string for the call as a whole.  */
   string *result = string::from_printf (m_ctxt,
 					"%s (%s)",
-					m_fn_ptr->get_debug_string (),
+					m_fn_ptr->get_debug_string_parens (prec),
 					argbuf);
 
   delete[] argbuf;
@@ -4680,10 +4786,11 @@ recording::array_access::visit_children (rvalue_visitor *v)
 recording::string *
 recording::array_access::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "%s[%s]",
-			      m_ptr->get_debug_string (),
-			      m_index->get_debug_string ());
+			      m_ptr->get_debug_string_parens (prec),
+			      m_index->get_debug_string_parens (prec));
 }
 
 /* Implementation of recording::memento::write_reproducer for
@@ -4735,9 +4842,10 @@ recording::access_field_of_lvalue::visit_children (rvalue_visitor *v)
 recording::string *
 recording::access_field_of_lvalue::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "%s.%s",
-			      m_lvalue->get_debug_string (),
+			      m_lvalue->get_debug_string_parens (prec),
 			      m_field->get_debug_string ());
 }
 
@@ -4787,9 +4895,10 @@ recording::access_field_rvalue::visit_children (rvalue_visitor *v)
 recording::string *
 recording::access_field_rvalue::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "%s.%s",
-			      m_rvalue->get_debug_string (),
+			      m_rvalue->get_debug_string_parens (prec),
 			      m_field->get_debug_string ());
 }
 
@@ -4840,9 +4949,10 @@ recording::dereference_field_rvalue::visit_children (rvalue_visitor *v)
 recording::string *
 recording::dereference_field_rvalue::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "%s->%s",
-			      m_rvalue->get_debug_string (),
+			      m_rvalue->get_debug_string_parens (prec),
 			      m_field->get_debug_string ());
 }
 
@@ -4891,9 +5001,10 @@ recording::dereference_rvalue::visit_children (rvalue_visitor *v)
 recording::string *
 recording::dereference_rvalue::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "*%s",
-			      m_rvalue->get_debug_string ());
+			      m_rvalue->get_debug_string_parens (prec));
 }
 
 /* Implementation of recording::memento::write_reproducer for
@@ -4939,9 +5050,10 @@ recording::get_address_of_lvalue::visit_children (rvalue_visitor *v)
 recording::string *
 recording::get_address_of_lvalue::make_debug_string ()
 {
+  enum precedence prec = get_precedence ();
   return string::from_printf (m_ctxt,
 			      "&%s",
-			      m_lvalue->get_debug_string ());
+			      m_lvalue->get_debug_string_parens (prec));
 }
 
 /* Implementation of recording::memento::write_reproducer for
diff --git a/gcc/jit/jit-recording.h b/gcc/jit/jit-recording.h
index 439e7ce62d9..d3170fecb7c 100644
--- a/gcc/jit/jit-recording.h
+++ b/gcc/jit/jit-recording.h
@@ -858,6 +858,27 @@ class rvalue_visitor
   virtual void visit (rvalue *rvalue) = 0;
 };
 
+/* When generating debug strings for rvalues we mimic C, so we need to
+   mimic C's precedence levels when handling compound expressions.
+   These are in order from strongest precedence to weakest.  */
+enum precedence
+{
+  PRECEDENCE_PRIMARY,
+  PRECEDENCE_POSTFIX,
+  PRECEDENCE_UNARY,
+  PRECEDENCE_CAST,
+  PRECEDENCE_MULTIPLICATIVE,
+  PRECEDENCE_ADDITIVE,
+  PRECEDENCE_SHIFT,
+  PRECEDENCE_RELATIONAL,
+  PRECEDENCE_EQUALITY,
+  PRECEDENCE_BITWISE_AND,
+  PRECEDENCE_BITWISE_XOR,
+  PRECEDENCE_BITWISE_IOR,
+  PRECEDENCE_LOGICAL_AND,
+  PRECEDENCE_LOGICAL_OR
+};
+
 class rvalue : public memento
 {
 public:
@@ -867,7 +888,8 @@ public:
   : memento (ctxt),
     m_loc (loc),
     m_type (type_),
-    m_scope (NULL)
+    m_scope (NULL),
+    m_parenthesized_string (NULL)
   {
     gcc_assert (type_);
   }
@@ -909,12 +931,20 @@ public:
 
   virtual const char *access_as_rvalue (reproducer &r);
 
+  /* Get the debug string, wrapped in parentheses.  */
+  const char *
+  get_debug_string_parens (enum precedence outer_prec);
+
+private:
+  virtual enum precedence get_precedence () const = 0;
+
 protected:
   location *m_loc;
   type *m_type;
 
  private:
   function *m_scope; /* NULL for globals, non-NULL for locals/params */
+  string *m_parenthesized_string;
 };
 
 class lvalue : public rvalue
@@ -977,6 +1007,7 @@ public:
 private:
   string * make_debug_string () { return m_name; }
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_PRIMARY; }
 
 private:
   string *m_name;
@@ -1161,6 +1192,7 @@ public:
 private:
   string * make_debug_string () { return m_name; }
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_PRIMARY; }
 
 private:
   enum gcc_jit_global_kind m_kind;
@@ -1185,6 +1217,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_PRIMARY; }
 
 private:
   HOST_TYPE m_value;
@@ -1206,6 +1239,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_PRIMARY; }
 
 private:
   string *m_value;
@@ -1231,6 +1265,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const {return PRECEDENCE_UNARY;}
 
 private:
   enum gcc_jit_unary_op m_op;
@@ -1257,6 +1292,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const;
 
 private:
   enum gcc_jit_binary_op m_op;
@@ -1284,6 +1320,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const;
 
 private:
   enum gcc_jit_comparison m_op;
@@ -1309,6 +1346,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_CAST; }
 
 private:
   rvalue *m_rvalue;
@@ -1330,6 +1368,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_POSTFIX; }
 
 private:
   function *m_func;
@@ -1352,6 +1391,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_POSTFIX; }
 
 private:
   rvalue *m_fn_ptr;
@@ -1377,6 +1417,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_POSTFIX; }
 
 private:
   rvalue *m_ptr;
@@ -1402,6 +1443,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_POSTFIX; }
 
 private:
   lvalue *m_lvalue;
@@ -1427,6 +1469,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_POSTFIX; }
 
 private:
   rvalue *m_rvalue;
@@ -1452,6 +1495,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_POSTFIX; }
 
 private:
   rvalue *m_rvalue;
@@ -1474,6 +1518,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_UNARY; }
 
 private:
   rvalue *m_rvalue;
@@ -1496,6 +1541,7 @@ public:
 private:
   string * make_debug_string ();
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_UNARY; }
 
 private:
   lvalue *m_lvalue;
@@ -1521,6 +1567,7 @@ public:
 private:
   string * make_debug_string () { return m_name; }
   void write_reproducer (reproducer &r);
+  enum precedence get_precedence () const { return PRECEDENCE_PRIMARY; }
 
 private:
   function *m_func;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 285fcb70518..66101a9d6dd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2015-06-16  David Malcolm  <dmalcolm@redhat.com>
+
+	PR jit/66539
+	* jit.dg/all-non-failing-tests.h: Add test-debug-strings.c.
+	* jit.dg/test-debug-strings.c: New test case.
+	* jit.dg/test-quadratic.c (make_calc_discriminant): Verify that
+	the discriminant has a sane debug string.
+
 2015-06-16  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/56766
diff --git a/gcc/testsuite/jit.dg/all-non-failing-tests.h b/gcc/testsuite/jit.dg/all-non-failing-tests.h
index 82ce7368482..f0000cc0c3e 100644
--- a/gcc/testsuite/jit.dg/all-non-failing-tests.h
+++ b/gcc/testsuite/jit.dg/all-non-failing-tests.h
@@ -64,6 +64,13 @@
 #undef create_code
 #undef verify_code
 
+/* test-debug-strings.c */
+#define create_code create_code_debug_strings
+#define verify_code verify_code_debug_strings
+#include "test-debug-strings.c"
+#undef create_code
+#undef verify_code
+
 /* test-dot-product.c */
 #define create_code create_code_dot_product
 #define verify_code verify_code_dot_product
diff --git a/gcc/testsuite/jit.dg/test-debug-strings.c b/gcc/testsuite/jit.dg/test-debug-strings.c
new file mode 100644
index 00000000000..e515a176257
--- /dev/null
+++ b/gcc/testsuite/jit.dg/test-debug-strings.c
@@ -0,0 +1,190 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "libgccjit.h"
+
+#include "harness.h"
+
+/* Build various compound expressions, and verify that they have sane debug
+   strings.  */
+void
+create_code (gcc_jit_context *ctxt, void *user_data)
+{
+  /* Make a singly-linked list type:
+      struct node
+      {
+       struct node *next;
+       int value;
+      };
+  */
+  gcc_jit_type *t_int =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_INT);
+  gcc_jit_struct *t_node =
+    gcc_jit_context_new_opaque_struct (ctxt, NULL, "node");
+  gcc_jit_type *t_node_ptr =
+    gcc_jit_type_get_pointer (gcc_jit_struct_as_type (t_node));
+  gcc_jit_field *f_next =
+    gcc_jit_context_new_field (ctxt, NULL, t_node_ptr, "next");
+  gcc_jit_field *f_value =
+    gcc_jit_context_new_field (ctxt, NULL, t_int, "value");
+  gcc_jit_field *fields[] = {f_next, f_value};
+  gcc_jit_struct_set_fields (t_node, NULL, 2, fields);
+
+  /* Create a dummy function so that we have locals/params to build
+     expressions with.  */
+  gcc_jit_type *t_void =
+    gcc_jit_context_get_type (ctxt, GCC_JIT_TYPE_VOID);
+  gcc_jit_function *fn =
+    gcc_jit_context_new_function (ctxt, NULL,
+				  GCC_JIT_FUNCTION_EXPORTED,
+				  t_void,
+				  "test_debug_strings",
+				  0, NULL, 0);
+  gcc_jit_rvalue *ptr =
+    gcc_jit_lvalue_as_rvalue (
+      gcc_jit_function_new_local (fn,
+				  NULL,
+				  t_node_ptr,
+				  "ptr"));
+  gcc_jit_rvalue *a =
+    gcc_jit_lvalue_as_rvalue (
+      gcc_jit_function_new_local (fn, NULL, t_int, "a"));
+  gcc_jit_rvalue *b =
+    gcc_jit_lvalue_as_rvalue (
+      gcc_jit_function_new_local (fn, NULL, t_int, "b"));
+  gcc_jit_rvalue *c =
+    gcc_jit_lvalue_as_rvalue (
+      gcc_jit_function_new_local (fn, NULL, t_int, "c"));
+  gcc_jit_rvalue *d =
+    gcc_jit_lvalue_as_rvalue (
+      gcc_jit_function_new_local (fn, NULL, t_int, "d"));
+
+#define CHECK_RVALUE_DEBUG_STRING(RVALUE, EXPECTED) \
+  CHECK_STRING_VALUE ( \
+    gcc_jit_object_get_debug_string (gcc_jit_rvalue_as_object (RVALUE)), \
+    (EXPECTED))
+
+#define CHECK_LVALUE_DEBUG_STRING(LVALUE, EXPECTED) \
+  CHECK_STRING_VALUE ( \
+    gcc_jit_object_get_debug_string (gcc_jit_lvalue_as_object (LVALUE)), \
+    (EXPECTED))
+
+  /* Verify various simple compound expressions.  */
+  {
+    CHECK_RVALUE_DEBUG_STRING (ptr, "ptr");
+
+    gcc_jit_lvalue *deref =
+      gcc_jit_rvalue_dereference_field (ptr,
+					NULL,
+					f_value);
+    CHECK_LVALUE_DEBUG_STRING (deref, "ptr->value");
+
+    gcc_jit_rvalue *deref_as_rvalue = gcc_jit_lvalue_as_rvalue (deref);
+
+#define BINOP(OP, A, B) \
+    gcc_jit_context_new_binary_op (ctxt, NULL, \
+				   GCC_JIT_BINARY_OP_##OP, t_int, (A), (B))
+#define COMPARISON(OP, A, B) \
+    gcc_jit_context_new_comparison (ctxt, NULL, \
+				    GCC_JIT_COMPARISON_##OP,(A), (B))
+
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (PLUS, deref_as_rvalue, deref_as_rvalue),
+      "ptr->value + ptr->value");
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (MULT, deref_as_rvalue, deref_as_rvalue),
+      "ptr->value * ptr->value");
+
+   /* Multiplication has higher precedence in C than addition, so this
+       dump shouldn't contain parentheses.  */
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (PLUS,
+	     BINOP (MULT, a, b),
+	     BINOP (MULT, c, d)),
+      "a * b + c * d");
+
+    /* ...but this one should.  */
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (MULT,
+	     BINOP (PLUS, a, b),
+	     BINOP (PLUS, c, d)),
+      "(a + b) * (c + d)");
+
+    /* Equal precedences don't need parentheses.  */
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (MULT,
+	     BINOP (MULT, a, b),
+	     BINOP (MULT, c, d)),
+      "a * b * c * d");
+
+    /* Comparisons and logical ops.  */
+    CHECK_RVALUE_DEBUG_STRING (
+      COMPARISON (LT, a, b),
+      "a < b");
+
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (LOGICAL_AND,
+	     COMPARISON (LT, a, b),
+	     COMPARISON (GT, c, d)),
+      "a < b && c > d");
+
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (LOGICAL_AND,
+	     BINOP (LOGICAL_OR,
+		    COMPARISON (LT, a, b),
+		    COMPARISON (LT, a, c)),
+	     BINOP (LOGICAL_OR,
+		    COMPARISON (GT, d, b),
+		    COMPARISON (GT, d, c))),
+      "(a < b || a < c) && (d > b || d > c)");
+
+    CHECK_RVALUE_DEBUG_STRING (
+      BINOP (LOGICAL_OR,
+	     BINOP (LOGICAL_AND,
+		    COMPARISON (LT, a, b),
+		    COMPARISON (LT, a, c)),
+	     BINOP (LOGICAL_AND,
+		    COMPARISON (GT, d, b),
+		    COMPARISON (GT, d, c))),
+      "a < b && a < c || d > b && d > c");
+
+#undef BINOP
+#undef COMPARISON
+  }
+
+  /* PR jit/66539 "Missing parentheses in jit dumps".
+     Construct the equivalent of
+       ((cast)ptr->next)->next
+     and verify that the appropriate parentheses appear in the debug
+     string.   */
+  {
+    /* "ptr->next". */
+    gcc_jit_lvalue *inner_deref =
+      gcc_jit_rvalue_dereference_field (ptr,
+					NULL,
+					f_next);
+    /* "((node *)ptr->next)"; the cast is redundant, purely
+       to exercise dumping.  */
+    gcc_jit_rvalue *test_cast =
+      gcc_jit_context_new_cast (ctxt, NULL,
+				gcc_jit_lvalue_as_rvalue (inner_deref),
+				t_node_ptr);
+    /* "((node *)ptr->next)->next".  */
+    gcc_jit_lvalue *outer_deref =
+      gcc_jit_rvalue_dereference_field (test_cast, /* gcc_jit_rvalue *ptr */
+					NULL, /* gcc_jit_location *loc */
+					f_next); /* gcc_jit_field *field */
+    CHECK_LVALUE_DEBUG_STRING (outer_deref,
+			       "((struct node *)ptr->next)->next");
+  }
+
+#undef CHECK_LVALUE_DEBUG_STRING
+}
+
+void
+verify_code (gcc_jit_context *ctxt, gcc_jit_result *result)
+{
+  CHECK_NON_NULL (result);
+  /* We don't actually build any functions above;
+     nothing more to verify.  */
+}
diff --git a/gcc/testsuite/jit.dg/test-quadratic.c b/gcc/testsuite/jit.dg/test-quadratic.c
index 715174c92f0..d83a4fb0571 100644
--- a/gcc/testsuite/jit.dg/test-quadratic.c
+++ b/gcc/testsuite/jit.dg/test-quadratic.c
@@ -176,16 +176,8 @@ make_calc_discriminant (struct quadratic_test *testcase)
 	  gcc_jit_param_as_rvalue (param_q),
 	  NULL, testcase->c));
 
-  gcc_jit_block_add_assignment (
-    blk, NULL,
-
-    /* q->discriminant =...  */
-    gcc_jit_rvalue_dereference_field (
-      gcc_jit_param_as_rvalue (param_q),
-      NULL,
-      testcase->discriminant),
-
-    /* (q->b * q->b) - (4 * q->a * q->c) */
+  /* (q->b * q->b) - (4 * q->a * q->c) */
+  gcc_jit_rvalue *rhs =
     gcc_jit_context_new_binary_op (
       testcase->ctxt, NULL,
       GCC_JIT_BINARY_OP_MINUS,
@@ -213,7 +205,21 @@ make_calc_discriminant (struct quadratic_test *testcase)
 	  testcase->ctxt, NULL,
 	  GCC_JIT_BINARY_OP_MULT,
 	  testcase->numeric_type,
-	  q_a, q_c)))); /* end of gcc_jit_function_add_assignment call.  */
+	  q_a, q_c)));
+
+  CHECK_STRING_VALUE (
+     gcc_jit_object_get_debug_string (gcc_jit_rvalue_as_object (rhs)),
+     "q->b * q->b - (double)4 * q->a * q->c");
+
+  gcc_jit_block_add_assignment (
+    blk, NULL,
+
+    /* q->discriminant =...  */
+    gcc_jit_rvalue_dereference_field (
+      gcc_jit_param_as_rvalue (param_q),
+      NULL,
+      testcase->discriminant),
+    rhs);
 
   gcc_jit_block_end_with_void_return (blk, NULL);
 }