| Message ID | 20110523165153.GC17079@tyan-ft48-01.lab.bos.redhat.com |
|---|---|
| State | New |
| Headers | show |
On Mon, 23 May 2011, Jakub Jelinek wrote: > Hi! > > This patch shuts up a warning about VLA bounds expression being unused. > start_decl adds the (usually SAVE_EXPR) expression to statements to make > sure it is evaluated, but if that happens in statement expression where > unused value warnings are postponed until we know what is the return value, > it will be warned on. Fixed by casting it to void. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk/4.6? > > 2011-05-23 Jakub Jelinek <jakub@redhat.com> > > PR c/49120 > * c-decl.c (start_decl): Convert expr to void_type_node. > > * gcc.dg/pr49120.c: New test. OK.
--- gcc/c-decl.c.jj 2011-05-11 19:39:04.000000000 +0200 +++ gcc/c-decl.c 2011-05-23 14:23:58.000000000 +0200 @@ -3942,7 +3942,7 @@ start_decl (struct c_declarator *declara return 0; if (expr) - add_stmt (expr); + add_stmt (fold_convert (void_type_node, expr)); if (TREE_CODE (decl) != FUNCTION_DECL && MAIN_NAME_P (DECL_NAME (decl))) warning (OPT_Wmain, "%q+D is usually a function", decl); --- gcc/testsuite/gcc.dg/pr49120.c.jj 2011-05-23 14:28:53.000000000 +0200 +++ gcc/testsuite/gcc.dg/pr49120.c 2011-05-23 14:28:26.000000000 +0200 @@ -0,0 +1,11 @@ +/* PR c/49120 */ +/* { dg-do compile } */ +/* { dg-options "-Wall" } */ + +int +main () +{ + int a = 1; + int c = ({ char b[a + 1]; b[0] = 0; b[0]; }); + return c; +}