On Tue, 19 Sep 2017, Nathan Sidwell wrote:
After recent changes, the member_name_cmp qsort comparator can indicate
A < B < A (i.e. lacks anti-commutativity) for distinct TYPE_DECL nodes
that have the same source location. If their order doesn't matter, the
comparator should return 0.
Where do we get such type decls?
The first instance that tripped qsort checking for me was in PCH generation.
I think by adding
What source example generates such type decls? That you've encountered this
suggests one of the invariants I was presuming is not true.
You can use the gcc_assert mentioned in the previous email on GCC
bootstrap/regtest to find examples. For me, the following example breaks (no
command line flags needed, just bare 'cc1plus t.i'):
struct
{
int a, b, c, d;
union
{
int e;
};
} s;
1436 gcc_assert (DECL_SOURCE_LOCATION (a) != DECL_SOURCE_LOCATION (b));