On Thu, Mar 09, 2017 at 10:06:53PM +0100, Jakub Jelinek wrote: > On Thu, Mar 09, 2017 at 12:00:48AM +0100, Marek Polacek wrote: > > We crash on an assert in strip_typedefs, because we find ourselves in a > > scenario where RESULT, the main variant of a struct, was modified in > > finalize_record_size (its TYPE_ALIGN changed), but its variants (T in > > strip_typedefs) weren't fixed-up yet; that will happen slightly later in > > finalize_type_size. So there's a discrepancy that confuses the code. > > > > This patch implements what Jason suggested to me on IRC, i.e., skip the > > attribute handling if RESULT is complete and T isn't. > > > > Bootstrapped/regtested on x86_64-linux, ok for trunk? > > > > 2017-03-08 Marek Polacek <pola...@redhat.com> > > > > PR c++/79900 - ICE in strip_typedefs > > * tree.c (strip_typedefs): Skip the attribute handling if T is > > a variant type which hasn't been updated yet. > > > > * g++.dg/warn/Wpadded-1.C: New test. > > > > diff --git gcc/testsuite/g++.dg/warn/Wpadded-1.C > > gcc/testsuite/g++.dg/warn/Wpadded-1.C > > index e69de29..b3f0581 100644 > > --- gcc/testsuite/g++.dg/warn/Wpadded-1.C > > +++ gcc/testsuite/g++.dg/warn/Wpadded-1.C > > @@ -0,0 +1,22 @@ > > +// PR c++/79900 - ICE in strip_typedefs > > +// { dg-do compile } > > +// { dg-options "-Wpadded" } > > + > > +template <class> struct A; > > +template <typename> struct B { // { dg-warning "padding struct size to > > alignment boundary" } > > + long _M_off; > > + int _M_state; > > +}; > > This fails on i686-linux, there is obviously no padding of struct size to > alignment boundary in that case.
Ah, of course... > Can't _M_state be e.g. char, then it would work at least on all targets > where long has alignment of at least 2 (that can be all of them)? > Perhaps also make _M_off long long or add a double or long double field. Like this? Passes with -m32. 2017-03-09 Marek Polacek <pola...@redhat.com> * g++.dg/warn/Wpadded-1.C: Change types of struct B fields. diff --git gcc/testsuite/g++.dg/warn/Wpadded-1.C gcc/testsuite/g++.dg/warn/Wpadded-1.C index b3f0581..af375a4 100644 --- gcc/testsuite/g++.dg/warn/Wpadded-1.C +++ gcc/testsuite/g++.dg/warn/Wpadded-1.C @@ -4,8 +4,8 @@ template <class> struct A; template <typename> struct B { // { dg-warning "padding struct size to alignment boundary" } - long _M_off; - int _M_state; + long long _M_off; + char _M_state; }; template <> struct A<char> { typedef B<int> pos_type; }; enum _Ios_Openmode {}; Marek