On Thu, Oct 01, 2015 at 02:06:36PM -0300, Eduardo Habkost wrote: > On Thu, Oct 01, 2015 at 11:35:52AM +1000, Richard Henderson wrote: > > On 09/30/2015 06:34 AM, Eduardo Habkost wrote: > > >Left shift of negative values is undefined behavior. Detected by clang: > > > qemu/target-i386/translate.c:2423:26: runtime error: > > > left shift of negative value -8 > > > > > >This changes the code to reverse the sign after the left shift. > > > > > >Signed-off-by: Eduardo Habkost <ehabk...@redhat.com> > > >--- > > > target-i386/translate.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > >diff --git a/target-i386/translate.c b/target-i386/translate.c > > >index 8b35de1..cc59b7e 100644 > > >--- a/target-i386/translate.c > > >+++ b/target-i386/translate.c > > >@@ -2420,7 +2420,7 @@ static void gen_pusha(DisasContext *s) > > > { > > > int i; > > > gen_op_movl_A0_reg(R_ESP); > > >- gen_op_addl_A0_im(-8 << s->dflag); > > >+ gen_op_addl_A0_im(-(8 << s->dflag)); > > > > Better as -8U << s->d_flag? > > That's even more confusing to me. I wouldn't want to require other > people to read the C specification to find out how many type conversions > are happening in that statement. (Because I will have to do that, to > find out what's the type of "-8U"). > > I would prefer an expression that doesn't involve any type conversion. > But you are more familiar with that code, so it's up to you.
Ping? I would really like to fix this warning to be able to enable check-mode by default in QEMU 2.5. Are there objections to get this patch included? -- Eduardo