-fstrict-volatile-bitfields doesn't work incorrectly in some cases when storing into a volatile bit-field.
Bernd provided a fix here about 1 year ago: http://gcc.gnu.org/ml/gcc-patches/2010-12/msg00217.html. But it is pending to trunk. Here are my humble opinions and hopefully we can revive it: 1. The fix could have helped lots of those who use volatile bit-fields, but has been blocked for 1 year by ABI version 1, a feature that I believe no one nowadays is using with latest gcc. Either error out ABI version 1 for some target, or just revising the failed ABI test case is OK for me. 2. This bug impacts all targets, especially target with strict-volatile-bitfields default enabled like ARM. The test case Bernd provided can be revised to a target independent case. +++ gcc/testsuite/gcc.dg/volatile-bitfields-4.c (revision 0) @@ -0,0 +1,15 @@ +/* { dg-do run } */ +/* { dg-options "-fstrict-volatile-bitfields" } */ + +extern void abort(void); +struct thing { + volatile unsigned short a: 8; + volatile unsigned short b: 8; +} t = {1,2}; + +int main() +{ + t.a = 3; + if (t.a !=3 || t.b !=2) abort(); + return 0; +}
