re PR c/33192 (__imag operator drops side effects in subexpr)

	PR c/33192
	* c-typeck.c (build_unary_op): Use omit_one_operand for
	IMAGPART_EXPR of real argument.

testsuite:
	* gcc.dg/imag-1.c: New test.

From-SVN: r141176

gcc/ChangeLog

+2008-10-16  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/33192
+	* c-typeck.c (build_unary_op): Use omit_one_operand for
+	IMAGPART_EXPR of real argument.
+
 2008-10-16  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/37664

gcc/c-typeck.c

@@ -3038,7 +3038,7 @@ build_unary_op (location_t location,
       else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
 	ret = fold_build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg);
       else
-	ret = convert (TREE_TYPE (arg), integer_zero_node);
+	ret = omit_one_operand (TREE_TYPE (arg), integer_zero_node, arg);
       goto return_build_unary_op;
 
     case PREINCREMENT_EXPR:

gcc/testsuite/ChangeLog

+2008-10-16  Joseph Myers  <joseph@codesourcery.com>
+
+	PR c/33192
+	* gcc.dg/imag-1.c: New test.
+
 2008-10-16  Daniel Kraft  <d@domob.eu>
 
 	* gfortran.dg/elemental_intrinsic_1.f03: New test.

gcc/testsuite/gcc.dg/imag-1.c

+/* Test for __imag__ side effects; see PR 33192.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do run } */
+/* { dg-options "-std=gnu99" } */
+
+extern void abort (void);
+extern void exit (int);
+
+int
+main (void)
+{
+  int i, j;
+  i = 1;
+  j = __imag__ ++i;
+  if (i != 2 || j != 0)
+    abort ();
+  return 0;
+}