sHi, On Thu, Jun 20, 2013 at 03:47:11PM +0100, Marcus Shawcroft wrote: > Hi, I've been looking at an issue in mysql compilation which appears > to be due to this patch. > > On 10 May 2013 18:27, Martin Jambor <mjam...@suse.cz> wrote: > > Hi, > > > > as we discover targets of previously indirect calls in ipa-inline and > > ipa-cp, we sometimes figure out that the targets are not a function. > > One typical example is when NULL is passed as a function pointer > > OK, this part makes sense to me. > > > parameter, another is when C++ member-pointer points to a virtual > > function and the overloaded field of the structure which can also hold > > pointers to non-virtual methods contains odd integer constants. > > I'm struggling to understand why such a member-pointer call would be > illegal in a well formed program. > > Attached is a fragment of code that demonstrates the issue I've been > looking at. When compiled at -O3 the 047i.inline dump tells me that: > > ipa-prop: Discovered direct call to non-function in unsigned int > A::foo(unsigned int (H::*)() const) const/11, making it unreachable. > not inlinable: unsigned int A::foo(unsigned int (H::*)() const) > const/11 -> void __builtin_unreachable()/12, function body not > available > > This behavior appears to be the explicit intent of the original patch, > the call to the member function pointer has been replaced with > __builtin_unreachable, but that looks like a legitimate call to me. > What am I missing?
Hm, the reason why I did this was that I misremembered that each branch, the one for virtual calls and the one for direct calls. But when I checked dumps, I realized it was not so, there is only one call when the branches join. I'll fix this promptly. Thanks for the report, Martin
