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[PATCH] Fix -Wunused-but-set-* in C with stmt expression and array in it (PR c/50179)
- From: Jakub Jelinek <jakub at redhat dot com>
- To: "Joseph S. Myers" <joseph at codesourcery dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Fri, 26 Aug 2011 00:43:32 +0200
- Subject: [PATCH] Fix -Wunused-but-set-* in C with stmt expression and array in it (PR c/50179)
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
Hi!
As the following testcase shows, if the last expression in statement
expression is array, mark_exp_read wasn't called on it.
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
ok for trunk/4.6?
2011-08-26 Jakub Jelinek <jakub@redhat.com>
PR c/50179
* c-typeck.c (c_process_expr_stmt): Skip over nops and
call mark_exp_read even if exprv is ADDR_EXPR.
* c-c++-common/Wunused-var-14.c: New test.
--- gcc/c-typeck.c.jj 2011-08-18 08:36:00.000000000 +0200
+++ gcc/c-typeck.c 2011-08-25 12:08:02.000000000 +0200
@@ -9109,7 +9109,11 @@ c_process_expr_stmt (location_t loc, tre
exprv = expr;
while (TREE_CODE (exprv) == COMPOUND_EXPR)
exprv = TREE_OPERAND (exprv, 1);
- if (DECL_P (exprv) || handled_component_p (exprv))
+ while (CONVERT_EXPR_P (exprv))
+ exprv = TREE_OPERAND (exprv, 0);
+ if (DECL_P (exprv)
+ || handled_component_p (exprv)
+ || TREE_CODE (exprv) == ADDR_EXPR)
mark_exp_read (exprv);
/* If the expression is not of a type to which we cannot assign a line
--- gcc/testsuite/c-c++-common/Wunused-var-14.c.jj 2011-08-25 12:04:39.000000000 +0200
+++ gcc/testsuite/c-c++-common/Wunused-var-14.c 2011-08-25 12:04:34.000000000 +0200
@@ -0,0 +1,13 @@
+/* PR c/50179 */
+/* { dg-options "-Wunused" } */
+/* { dg-do compile } */
+
+void bar (int, ...);
+
+char *
+foo (void)
+{
+ bar (1, (__extension__ ({ static char b[2]; b[0] = 1; b; })));
+ bar (1, ({ static char c[2]; c[0] = 1; c; }));
+ return ({ static char d[2]; d[0] = 1; d; });
+}
Jakub