re PR c/66341 (Some casts wrongly produce a lvalue)

	PR c/66341
	* c-typeck.c (build_c_cast): Wrap VALUE into NON_LVALUE_EXPR if
	it is a lvalue.

	* gcc.dg/lvalue-8.c: New test.

From-SVN: r224115

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 69344bb7bb10b372283116a44ca7442d1d94e1e1..d6be87f0742465bacb769c1644154f020cbded97 100644 (file)
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,9 @@
+2015-06-04  Marek Polacek  <polacek@redhat.com>
+
+       PR c/66341
+       * c-typeck.c (build_c_cast): Wrap VALUE into NON_LVALUE_EXPR if
+       it is a lvalue.
+
 2015-06-03  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
 
        * c-decl.c (warn_cxx_compat_finish_struct): New parameters code, record_loc.

diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index f55d4c60bfc54dae7e7dd458c85432a5467e3b64..6b313f30b08f1788bd98e2e0844e390f4f7b70a6 100644 (file)
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -5195,7 +5195,7 @@ build_c_cast (location_t loc, tree type, tree expr)
     }
 
   /* Don't let a cast be an lvalue.  */
-  if (value == expr)
+  if (lvalue_p (value))
     value = non_lvalue_loc (loc, value);
 
   /* Don't allow the results of casting to floating-point or complex

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index a74be77df88b4d59d6589fb78a425c0eb56a2bde..3092acf1fa6da71f51f773f280746b2a734b08fe 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2015-06-04  Marek Polacek  <polacek@redhat.com>
+
+       PR c/66341
+       * gcc.dg/lvalue-8.c: New test.
+
 2015-06-03  Manuel López-Ibáñez  <manu@gcc.gnu.org>
            Paolo Carlini  <paolo.carlini@oracle.com>
 

diff --git a/gcc/testsuite/gcc.dg/lvalue-8.c b/gcc/testsuite/gcc.dg/lvalue-8.c
new file mode 100644 (file)
index 0000000..04eeb71
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/lvalue-8.c
@@ -0,0 +1,19 @@
+/* PR c/66341 */
+/* { dg-do compile } */
+
+void
+foo (int *p)
+{
+  p = 0;
+  /* A cast does not yield an lvalue.  */
+  (int *) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  /* A cast to a qualified type has the same effect as a cast
+     to the unqualified version of the type.  */
+  (int *const) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  (int *) (char *) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  (int *) (char *) (int *) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  (int *) (char *) (int *) (char *) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  (int *) (double *) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  (int *) (int *) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+  (int *) (int *const) p = 0; /* { dg-error "lvalue required as left operand of assignment" } */
+}