| Message ID | 20110423063629.GB17079@tyan-ft48-01.lab.bos.redhat.com |
|---|---|
| State | New |
| Headers | show |
On Sat, Apr 23, 2011 at 8:36 AM, Jakub Jelinek <jakub@redhat.com> wrote: > Hi! > > Roger changed fold_convert* back in 2007 to not actually convert to void > GIMPLE_MODIFY_STMT: > http://gcc.gnu.org/ml/gcc-patches/2007-01/msg00279.html > as GIMPLE_MODIFY_STMT didn't have TREE_TYPE and thus converting it to > void has been difficult. > That == GIMPLE_MODIFY_STMT check has been changed into == MODIFY_EXPR > during real tuplification apparently, but MODIFY_EXPR has a type > and can be converted to void_type_node type just fine. Not doing so > breaks e.g. following testcase, because fold_convert_loc (void_type_node, modify_expr); > doesn't actually yield a void_type_node tree and if it is inside of > NON_LVALUE_EXPR with void type, the NON_LVALUE_EXPR won't be removed. > > Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, > ok for trunk/4.6? Ok. Thanks, Richard. > 2011-04-23 Jakub Jelinek <jakub@redhat.com> > > PR c/48685 > * fold-const.c (fold_convert_loc): Add NOP_EXPR when casting > to VOID_TYPE even around MODIFY_EXPR. > > * gcc.dg/pr48685.c: New test. > > --- gcc/fold-const.c.jj 2011-04-18 11:28:05.000000000 +0200 > +++ gcc/fold-const.c 2011-04-22 21:21:51.000000000 +0200 > @@ -2029,8 +2029,6 @@ fold_convert_loc (location_t loc, tree t > > case VOID_TYPE: > tem = fold_ignored_result (arg); > - if (TREE_CODE (tem) == MODIFY_EXPR) > - goto fold_convert_exit; > return fold_build1_loc (loc, NOP_EXPR, type, tem); > > default: > --- gcc/testsuite/gcc.dg/pr48685.c.jj 2011-04-22 21:24:01.000000000 +0200 > +++ gcc/testsuite/gcc.dg/pr48685.c 2011-04-22 21:24:14.000000000 +0200 > @@ -0,0 +1,11 @@ > +/* PR c/48685 */ > +/* { dg-do compile } */ > +/* { dg-options "-O2" } */ > + > +int > +main () > +{ > + int v = 1; > + (void) (1 == 2 ? (void) 0 : (v = 0)); > + return v; > +} > > Jakub >
--- gcc/fold-const.c.jj 2011-04-18 11:28:05.000000000 +0200 +++ gcc/fold-const.c 2011-04-22 21:21:51.000000000 +0200 @@ -2029,8 +2029,6 @@ fold_convert_loc (location_t loc, tree t case VOID_TYPE: tem = fold_ignored_result (arg); - if (TREE_CODE (tem) == MODIFY_EXPR) - goto fold_convert_exit; return fold_build1_loc (loc, NOP_EXPR, type, tem); default: --- gcc/testsuite/gcc.dg/pr48685.c.jj 2011-04-22 21:24:01.000000000 +0200 +++ gcc/testsuite/gcc.dg/pr48685.c 2011-04-22 21:24:14.000000000 +0200 @@ -0,0 +1,11 @@ +/* PR c/48685 */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +int +main () +{ + int v = 1; + (void) (1 == 2 ? (void) 0 : (v = 0)); + return v; +}